sqlglot.dialects.mysql

   1from __future__ import annotations
   2
   3import typing as t
   4
   5from sqlglot import exp, generator, parser, tokens, transforms
   6from sqlglot.dialects.dialect import (
   7    Dialect,
   8    NormalizationStrategy,
   9    arrow_json_extract_sql,
  10    date_add_interval_sql,
  11    datestrtodate_sql,
  12    build_formatted_time,
  13    isnull_to_is_null,
  14    length_or_char_length_sql,
  15    max_or_greatest,
  16    min_or_least,
  17    no_ilike_sql,
  18    no_paren_current_date_sql,
  19    no_pivot_sql,
  20    no_tablesample_sql,
  21    no_trycast_sql,
  22    build_date_delta,
  23    build_date_delta_with_interval,
  24    rename_func,
  25    strposition_sql,
  26    unit_to_var,
  27    trim_sql,
  28    timestrtotime_sql,
  29)
  30from sqlglot.generator import unsupported_args
  31from sqlglot.helper import seq_get
  32from sqlglot.tokens import TokenType
  33
  34
  35def _show_parser(*args: t.Any, **kwargs: t.Any) -> t.Callable[[MySQL.Parser], exp.Show]:
  36    def _parse(self: MySQL.Parser) -> exp.Show:
  37        return self._parse_show_mysql(*args, **kwargs)
  38
  39    return _parse
  40
  41
  42def _date_trunc_sql(self: MySQL.Generator, expression: exp.DateTrunc) -> str:
  43    expr = self.sql(expression, "this")
  44    unit = expression.text("unit").upper()
  45
  46    if unit == "WEEK":
  47        concat = f"CONCAT(YEAR({expr}), ' ', WEEK({expr}, 1), ' 1')"
  48        date_format = "%Y %u %w"
  49    elif unit == "MONTH":
  50        concat = f"CONCAT(YEAR({expr}), ' ', MONTH({expr}), ' 1')"
  51        date_format = "%Y %c %e"
  52    elif unit == "QUARTER":
  53        concat = f"CONCAT(YEAR({expr}), ' ', QUARTER({expr}) * 3 - 2, ' 1')"
  54        date_format = "%Y %c %e"
  55    elif unit == "YEAR":
  56        concat = f"CONCAT(YEAR({expr}), ' 1 1')"
  57        date_format = "%Y %c %e"
  58    else:
  59        if unit != "DAY":
  60            self.unsupported(f"Unexpected interval unit: {unit}")
  61        return self.func("DATE", expr)
  62
  63    return self.func("STR_TO_DATE", concat, f"'{date_format}'")
  64
  65
  66# All specifiers for time parts (as opposed to date parts)
  67# https://dev.mysql.com/doc/refman/8.0/en/date-and-time-functions.html#function_date-format
  68TIME_SPECIFIERS = {"f", "H", "h", "I", "i", "k", "l", "p", "r", "S", "s", "T"}
  69
  70
  71def _has_time_specifier(date_format: str) -> bool:
  72    i = 0
  73    length = len(date_format)
  74
  75    while i < length:
  76        if date_format[i] == "%":
  77            i += 1
  78            if i < length and date_format[i] in TIME_SPECIFIERS:
  79                return True
  80        i += 1
  81    return False
  82
  83
  84def _str_to_date(args: t.List) -> exp.StrToDate | exp.StrToTime:
  85    mysql_date_format = seq_get(args, 1)
  86    date_format = MySQL.format_time(mysql_date_format)
  87    this = seq_get(args, 0)
  88
  89    if mysql_date_format and _has_time_specifier(mysql_date_format.name):
  90        return exp.StrToTime(this=this, format=date_format)
  91
  92    return exp.StrToDate(this=this, format=date_format)
  93
  94
  95def _str_to_date_sql(
  96    self: MySQL.Generator, expression: exp.StrToDate | exp.StrToTime | exp.TsOrDsToDate
  97) -> str:
  98    return self.func("STR_TO_DATE", expression.this, self.format_time(expression))
  99
 100
 101def _unix_to_time_sql(self: MySQL.Generator, expression: exp.UnixToTime) -> str:
 102    scale = expression.args.get("scale")
 103    timestamp = expression.this
 104
 105    if scale in (None, exp.UnixToTime.SECONDS):
 106        return self.func("FROM_UNIXTIME", timestamp, self.format_time(expression))
 107
 108    return self.func(
 109        "FROM_UNIXTIME",
 110        exp.Div(this=timestamp, expression=exp.func("POW", 10, scale)),
 111        self.format_time(expression),
 112    )
 113
 114
 115def date_add_sql(
 116    kind: str,
 117) -> t.Callable[[generator.Generator, exp.Expression], str]:
 118    def func(self: generator.Generator, expression: exp.Expression) -> str:
 119        return self.func(
 120            f"DATE_{kind}",
 121            expression.this,
 122            exp.Interval(this=expression.expression, unit=unit_to_var(expression)),
 123        )
 124
 125    return func
 126
 127
 128def _ts_or_ds_to_date_sql(self: MySQL.Generator, expression: exp.TsOrDsToDate) -> str:
 129    time_format = expression.args.get("format")
 130    return _str_to_date_sql(self, expression) if time_format else self.func("DATE", expression.this)
 131
 132
 133def _remove_ts_or_ds_to_date(
 134    to_sql: t.Optional[t.Callable[[MySQL.Generator, exp.Expression], str]] = None,
 135    args: t.Tuple[str, ...] = ("this",),
 136) -> t.Callable[[MySQL.Generator, exp.Func], str]:
 137    def func(self: MySQL.Generator, expression: exp.Func) -> str:
 138        for arg_key in args:
 139            arg = expression.args.get(arg_key)
 140            if isinstance(arg, exp.TsOrDsToDate) and not arg.args.get("format"):
 141                expression.set(arg_key, arg.this)
 142
 143        return to_sql(self, expression) if to_sql else self.function_fallback_sql(expression)
 144
 145    return func
 146
 147
 148class MySQL(Dialect):
 149    PROMOTE_TO_INFERRED_DATETIME_TYPE = True
 150
 151    # https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
 152    IDENTIFIERS_CAN_START_WITH_DIGIT = True
 153
 154    # We default to treating all identifiers as case-sensitive, since it matches MySQL's
 155    # behavior on Linux systems. For MacOS and Windows systems, one can override this
 156    # setting by specifying `dialect="mysql, normalization_strategy = lowercase"`.
 157    #
 158    # See also https://dev.mysql.com/doc/refman/8.2/en/identifier-case-sensitivity.html
 159    NORMALIZATION_STRATEGY = NormalizationStrategy.CASE_SENSITIVE
 160
 161    TIME_FORMAT = "'%Y-%m-%d %T'"
 162    DPIPE_IS_STRING_CONCAT = False
 163    SUPPORTS_USER_DEFINED_TYPES = False
 164    SUPPORTS_SEMI_ANTI_JOIN = False
 165    SAFE_DIVISION = True
 166
 167    # https://prestodb.io/docs/current/functions/datetime.html#mysql-date-functions
 168    TIME_MAPPING = {
 169        "%M": "%B",
 170        "%c": "%-m",
 171        "%e": "%-d",
 172        "%h": "%I",
 173        "%i": "%M",
 174        "%s": "%S",
 175        "%u": "%W",
 176        "%k": "%-H",
 177        "%l": "%-I",
 178        "%T": "%H:%M:%S",
 179        "%W": "%A",
 180    }
 181
 182    class Tokenizer(tokens.Tokenizer):
 183        QUOTES = ["'", '"']
 184        COMMENTS = ["--", "#", ("/*", "*/")]
 185        IDENTIFIERS = ["`"]
 186        STRING_ESCAPES = ["'", '"', "\\"]
 187        BIT_STRINGS = [("b'", "'"), ("B'", "'"), ("0b", "")]
 188        HEX_STRINGS = [("x'", "'"), ("X'", "'"), ("0x", "")]
 189
 190        NESTED_COMMENTS = False
 191
 192        KEYWORDS = {
 193            **tokens.Tokenizer.KEYWORDS,
 194            "CHARSET": TokenType.CHARACTER_SET,
 195            # The DESCRIBE and EXPLAIN statements are synonyms.
 196            # https://dev.mysql.com/doc/refman/8.4/en/explain.html
 197            "BLOB": TokenType.BLOB,
 198            "DISTINCTROW": TokenType.DISTINCT,
 199            "EXPLAIN": TokenType.DESCRIBE,
 200            "FORCE": TokenType.FORCE,
 201            "IGNORE": TokenType.IGNORE,
 202            "KEY": TokenType.KEY,
 203            "LOCK TABLES": TokenType.COMMAND,
 204            "LONGBLOB": TokenType.LONGBLOB,
 205            "LONGTEXT": TokenType.LONGTEXT,
 206            "MEDIUMBLOB": TokenType.MEDIUMBLOB,
 207            "TINYBLOB": TokenType.TINYBLOB,
 208            "TINYTEXT": TokenType.TINYTEXT,
 209            "MEDIUMTEXT": TokenType.MEDIUMTEXT,
 210            "MEDIUMINT": TokenType.MEDIUMINT,
 211            "MEMBER OF": TokenType.MEMBER_OF,
 212            "SEPARATOR": TokenType.SEPARATOR,
 213            "SERIAL": TokenType.SERIAL,
 214            "START": TokenType.BEGIN,
 215            "SIGNED": TokenType.BIGINT,
 216            "SIGNED INTEGER": TokenType.BIGINT,
 217            "TIMESTAMP": TokenType.TIMESTAMPTZ,
 218            "UNLOCK TABLES": TokenType.COMMAND,
 219            "UNSIGNED": TokenType.UBIGINT,
 220            "UNSIGNED INTEGER": TokenType.UBIGINT,
 221            "YEAR": TokenType.YEAR,
 222            "_ARMSCII8": TokenType.INTRODUCER,
 223            "_ASCII": TokenType.INTRODUCER,
 224            "_BIG5": TokenType.INTRODUCER,
 225            "_BINARY": TokenType.INTRODUCER,
 226            "_CP1250": TokenType.INTRODUCER,
 227            "_CP1251": TokenType.INTRODUCER,
 228            "_CP1256": TokenType.INTRODUCER,
 229            "_CP1257": TokenType.INTRODUCER,
 230            "_CP850": TokenType.INTRODUCER,
 231            "_CP852": TokenType.INTRODUCER,
 232            "_CP866": TokenType.INTRODUCER,
 233            "_CP932": TokenType.INTRODUCER,
 234            "_DEC8": TokenType.INTRODUCER,
 235            "_EUCJPMS": TokenType.INTRODUCER,
 236            "_EUCKR": TokenType.INTRODUCER,
 237            "_GB18030": TokenType.INTRODUCER,
 238            "_GB2312": TokenType.INTRODUCER,
 239            "_GBK": TokenType.INTRODUCER,
 240            "_GEOSTD8": TokenType.INTRODUCER,
 241            "_GREEK": TokenType.INTRODUCER,
 242            "_HEBREW": TokenType.INTRODUCER,
 243            "_HP8": TokenType.INTRODUCER,
 244            "_KEYBCS2": TokenType.INTRODUCER,
 245            "_KOI8R": TokenType.INTRODUCER,
 246            "_KOI8U": TokenType.INTRODUCER,
 247            "_LATIN1": TokenType.INTRODUCER,
 248            "_LATIN2": TokenType.INTRODUCER,
 249            "_LATIN5": TokenType.INTRODUCER,
 250            "_LATIN7": TokenType.INTRODUCER,
 251            "_MACCE": TokenType.INTRODUCER,
 252            "_MACROMAN": TokenType.INTRODUCER,
 253            "_SJIS": TokenType.INTRODUCER,
 254            "_SWE7": TokenType.INTRODUCER,
 255            "_TIS620": TokenType.INTRODUCER,
 256            "_UCS2": TokenType.INTRODUCER,
 257            "_UJIS": TokenType.INTRODUCER,
 258            # https://dev.mysql.com/doc/refman/8.0/en/string-literals.html
 259            "_UTF8": TokenType.INTRODUCER,
 260            "_UTF16": TokenType.INTRODUCER,
 261            "_UTF16LE": TokenType.INTRODUCER,
 262            "_UTF32": TokenType.INTRODUCER,
 263            "_UTF8MB3": TokenType.INTRODUCER,
 264            "_UTF8MB4": TokenType.INTRODUCER,
 265            "@@": TokenType.SESSION_PARAMETER,
 266        }
 267
 268        COMMANDS = {*tokens.Tokenizer.COMMANDS, TokenType.REPLACE} - {TokenType.SHOW}
 269
 270    class Parser(parser.Parser):
 271        FUNC_TOKENS = {
 272            *parser.Parser.FUNC_TOKENS,
 273            TokenType.DATABASE,
 274            TokenType.SCHEMA,
 275            TokenType.VALUES,
 276        }
 277
 278        CONJUNCTION = {
 279            **parser.Parser.CONJUNCTION,
 280            TokenType.DAMP: exp.And,
 281            TokenType.XOR: exp.Xor,
 282        }
 283
 284        DISJUNCTION = {
 285            **parser.Parser.DISJUNCTION,
 286            TokenType.DPIPE: exp.Or,
 287        }
 288
 289        TABLE_ALIAS_TOKENS = (
 290            parser.Parser.TABLE_ALIAS_TOKENS - parser.Parser.TABLE_INDEX_HINT_TOKENS
 291        )
 292
 293        RANGE_PARSERS = {
 294            **parser.Parser.RANGE_PARSERS,
 295            TokenType.MEMBER_OF: lambda self, this: self.expression(
 296                exp.JSONArrayContains,
 297                this=this,
 298                expression=self._parse_wrapped(self._parse_expression),
 299            ),
 300        }
 301
 302        FUNCTIONS = {
 303            **parser.Parser.FUNCTIONS,
 304            "CONVERT_TZ": lambda args: exp.ConvertTimezone(
 305                source_tz=seq_get(args, 1), target_tz=seq_get(args, 2), timestamp=seq_get(args, 0)
 306            ),
 307            "CURDATE": exp.CurrentDate.from_arg_list,
 308            "DATE": lambda args: exp.TsOrDsToDate(this=seq_get(args, 0)),
 309            "DATE_ADD": build_date_delta_with_interval(exp.DateAdd),
 310            "DATE_FORMAT": build_formatted_time(exp.TimeToStr, "mysql"),
 311            "DATE_SUB": build_date_delta_with_interval(exp.DateSub),
 312            "DAY": lambda args: exp.Day(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 313            "DAYOFMONTH": lambda args: exp.DayOfMonth(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 314            "DAYOFWEEK": lambda args: exp.DayOfWeek(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 315            "DAYOFYEAR": lambda args: exp.DayOfYear(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 316            "FORMAT": exp.NumberToStr.from_arg_list,
 317            "FROM_UNIXTIME": build_formatted_time(exp.UnixToTime, "mysql"),
 318            "ISNULL": isnull_to_is_null,
 319            "LENGTH": lambda args: exp.Length(this=seq_get(args, 0), binary=True),
 320            "MAKETIME": exp.TimeFromParts.from_arg_list,
 321            "MONTH": lambda args: exp.Month(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 322            "MONTHNAME": lambda args: exp.TimeToStr(
 323                this=exp.TsOrDsToDate(this=seq_get(args, 0)),
 324                format=exp.Literal.string("%B"),
 325            ),
 326            "SCHEMA": exp.CurrentSchema.from_arg_list,
 327            "DATABASE": exp.CurrentSchema.from_arg_list,
 328            "STR_TO_DATE": _str_to_date,
 329            "TIMESTAMPDIFF": build_date_delta(exp.TimestampDiff),
 330            "TO_DAYS": lambda args: exp.paren(
 331                exp.DateDiff(
 332                    this=exp.TsOrDsToDate(this=seq_get(args, 0)),
 333                    expression=exp.TsOrDsToDate(this=exp.Literal.string("0000-01-01")),
 334                    unit=exp.var("DAY"),
 335                )
 336                + 1
 337            ),
 338            "WEEK": lambda args: exp.Week(
 339                this=exp.TsOrDsToDate(this=seq_get(args, 0)), mode=seq_get(args, 1)
 340            ),
 341            "WEEKOFYEAR": lambda args: exp.WeekOfYear(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 342            "YEAR": lambda args: exp.Year(this=exp.TsOrDsToDate(this=seq_get(args, 0))),
 343        }
 344
 345        FUNCTION_PARSERS = {
 346            **parser.Parser.FUNCTION_PARSERS,
 347            "CHAR": lambda self: self.expression(
 348                exp.Chr,
 349                expressions=self._parse_csv(self._parse_assignment),
 350                charset=self._match(TokenType.USING) and self._parse_var(),
 351            ),
 352            "GROUP_CONCAT": lambda self: self._parse_group_concat(),
 353            # https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_values
 354            "VALUES": lambda self: self.expression(
 355                exp.Anonymous, this="VALUES", expressions=[self._parse_id_var()]
 356            ),
 357            "JSON_VALUE": lambda self: self._parse_json_value(),
 358        }
 359
 360        STATEMENT_PARSERS = {
 361            **parser.Parser.STATEMENT_PARSERS,
 362            TokenType.SHOW: lambda self: self._parse_show(),
 363        }
 364
 365        SHOW_PARSERS = {
 366            "BINARY LOGS": _show_parser("BINARY LOGS"),
 367            "MASTER LOGS": _show_parser("BINARY LOGS"),
 368            "BINLOG EVENTS": _show_parser("BINLOG EVENTS"),
 369            "CHARACTER SET": _show_parser("CHARACTER SET"),
 370            "CHARSET": _show_parser("CHARACTER SET"),
 371            "COLLATION": _show_parser("COLLATION"),
 372            "FULL COLUMNS": _show_parser("COLUMNS", target="FROM", full=True),
 373            "COLUMNS": _show_parser("COLUMNS", target="FROM"),
 374            "CREATE DATABASE": _show_parser("CREATE DATABASE", target=True),
 375            "CREATE EVENT": _show_parser("CREATE EVENT", target=True),
 376            "CREATE FUNCTION": _show_parser("CREATE FUNCTION", target=True),
 377            "CREATE PROCEDURE": _show_parser("CREATE PROCEDURE", target=True),
 378            "CREATE TABLE": _show_parser("CREATE TABLE", target=True),
 379            "CREATE TRIGGER": _show_parser("CREATE TRIGGER", target=True),
 380            "CREATE VIEW": _show_parser("CREATE VIEW", target=True),
 381            "DATABASES": _show_parser("DATABASES"),
 382            "SCHEMAS": _show_parser("DATABASES"),
 383            "ENGINE": _show_parser("ENGINE", target=True),
 384            "STORAGE ENGINES": _show_parser("ENGINES"),
 385            "ENGINES": _show_parser("ENGINES"),
 386            "ERRORS": _show_parser("ERRORS"),
 387            "EVENTS": _show_parser("EVENTS"),
 388            "FUNCTION CODE": _show_parser("FUNCTION CODE", target=True),
 389            "FUNCTION STATUS": _show_parser("FUNCTION STATUS"),
 390            "GRANTS": _show_parser("GRANTS", target="FOR"),
 391            "INDEX": _show_parser("INDEX", target="FROM"),
 392            "MASTER STATUS": _show_parser("MASTER STATUS"),
 393            "OPEN TABLES": _show_parser("OPEN TABLES"),
 394            "PLUGINS": _show_parser("PLUGINS"),
 395            "PROCEDURE CODE": _show_parser("PROCEDURE CODE", target=True),
 396            "PROCEDURE STATUS": _show_parser("PROCEDURE STATUS"),
 397            "PRIVILEGES": _show_parser("PRIVILEGES"),
 398            "FULL PROCESSLIST": _show_parser("PROCESSLIST", full=True),
 399            "PROCESSLIST": _show_parser("PROCESSLIST"),
 400            "PROFILE": _show_parser("PROFILE"),
 401            "PROFILES": _show_parser("PROFILES"),
 402            "RELAYLOG EVENTS": _show_parser("RELAYLOG EVENTS"),
 403            "REPLICAS": _show_parser("REPLICAS"),
 404            "SLAVE HOSTS": _show_parser("REPLICAS"),
 405            "REPLICA STATUS": _show_parser("REPLICA STATUS"),
 406            "SLAVE STATUS": _show_parser("REPLICA STATUS"),
 407            "GLOBAL STATUS": _show_parser("STATUS", global_=True),
 408            "SESSION STATUS": _show_parser("STATUS"),
 409            "STATUS": _show_parser("STATUS"),
 410            "TABLE STATUS": _show_parser("TABLE STATUS"),
 411            "FULL TABLES": _show_parser("TABLES", full=True),
 412            "TABLES": _show_parser("TABLES"),
 413            "TRIGGERS": _show_parser("TRIGGERS"),
 414            "GLOBAL VARIABLES": _show_parser("VARIABLES", global_=True),
 415            "SESSION VARIABLES": _show_parser("VARIABLES"),
 416            "VARIABLES": _show_parser("VARIABLES"),
 417            "WARNINGS": _show_parser("WARNINGS"),
 418        }
 419
 420        PROPERTY_PARSERS = {
 421            **parser.Parser.PROPERTY_PARSERS,
 422            "LOCK": lambda self: self._parse_property_assignment(exp.LockProperty),
 423        }
 424
 425        SET_PARSERS = {
 426            **parser.Parser.SET_PARSERS,
 427            "PERSIST": lambda self: self._parse_set_item_assignment("PERSIST"),
 428            "PERSIST_ONLY": lambda self: self._parse_set_item_assignment("PERSIST_ONLY"),
 429            "CHARACTER SET": lambda self: self._parse_set_item_charset("CHARACTER SET"),
 430            "CHARSET": lambda self: self._parse_set_item_charset("CHARACTER SET"),
 431            "NAMES": lambda self: self._parse_set_item_names(),
 432        }
 433
 434        CONSTRAINT_PARSERS = {
 435            **parser.Parser.CONSTRAINT_PARSERS,
 436            "FULLTEXT": lambda self: self._parse_index_constraint(kind="FULLTEXT"),
 437            "INDEX": lambda self: self._parse_index_constraint(),
 438            "KEY": lambda self: self._parse_index_constraint(),
 439            "SPATIAL": lambda self: self._parse_index_constraint(kind="SPATIAL"),
 440        }
 441
 442        ALTER_PARSERS = {
 443            **parser.Parser.ALTER_PARSERS,
 444            "MODIFY": lambda self: self._parse_alter_table_alter(),
 445        }
 446
 447        ALTER_ALTER_PARSERS = {
 448            **parser.Parser.ALTER_ALTER_PARSERS,
 449            "INDEX": lambda self: self._parse_alter_table_alter_index(),
 450        }
 451
 452        SCHEMA_UNNAMED_CONSTRAINTS = {
 453            *parser.Parser.SCHEMA_UNNAMED_CONSTRAINTS,
 454            "FULLTEXT",
 455            "INDEX",
 456            "KEY",
 457            "SPATIAL",
 458        }
 459
 460        PROFILE_TYPES: parser.OPTIONS_TYPE = {
 461            **dict.fromkeys(("ALL", "CPU", "IPC", "MEMORY", "SOURCE", "SWAPS"), tuple()),
 462            "BLOCK": ("IO",),
 463            "CONTEXT": ("SWITCHES",),
 464            "PAGE": ("FAULTS",),
 465        }
 466
 467        TYPE_TOKENS = {
 468            *parser.Parser.TYPE_TOKENS,
 469            TokenType.SET,
 470        }
 471
 472        ENUM_TYPE_TOKENS = {
 473            *parser.Parser.ENUM_TYPE_TOKENS,
 474            TokenType.SET,
 475        }
 476
 477        # SELECT [ ALL | DISTINCT | DISTINCTROW ] [ <OPERATION_MODIFIERS> ]
 478        OPERATION_MODIFIERS = {
 479            "HIGH_PRIORITY",
 480            "STRAIGHT_JOIN",
 481            "SQL_SMALL_RESULT",
 482            "SQL_BIG_RESULT",
 483            "SQL_BUFFER_RESULT",
 484            "SQL_NO_CACHE",
 485            "SQL_CALC_FOUND_ROWS",
 486        }
 487
 488        LOG_DEFAULTS_TO_LN = True
 489        STRING_ALIASES = True
 490        VALUES_FOLLOWED_BY_PAREN = False
 491        SUPPORTS_PARTITION_SELECTION = True
 492
 493        def _parse_generated_as_identity(
 494            self,
 495        ) -> (
 496            exp.GeneratedAsIdentityColumnConstraint
 497            | exp.ComputedColumnConstraint
 498            | exp.GeneratedAsRowColumnConstraint
 499        ):
 500            this = super()._parse_generated_as_identity()
 501
 502            if self._match_texts(("STORED", "VIRTUAL")):
 503                persisted = self._prev.text.upper() == "STORED"
 504
 505                if isinstance(this, exp.ComputedColumnConstraint):
 506                    this.set("persisted", persisted)
 507                elif isinstance(this, exp.GeneratedAsIdentityColumnConstraint):
 508                    this = self.expression(
 509                        exp.ComputedColumnConstraint, this=this.expression, persisted=persisted
 510                    )
 511
 512            return this
 513
 514        def _parse_primary_key_part(self) -> t.Optional[exp.Expression]:
 515            this = self._parse_id_var()
 516            if not self._match(TokenType.L_PAREN):
 517                return this
 518
 519            expression = self._parse_number()
 520            self._match_r_paren()
 521            return self.expression(exp.ColumnPrefix, this=this, expression=expression)
 522
 523        def _parse_index_constraint(
 524            self, kind: t.Optional[str] = None
 525        ) -> exp.IndexColumnConstraint:
 526            if kind:
 527                self._match_texts(("INDEX", "KEY"))
 528
 529            this = self._parse_id_var(any_token=False)
 530            index_type = self._match(TokenType.USING) and self._advance_any() and self._prev.text
 531            expressions = self._parse_wrapped_csv(self._parse_ordered)
 532
 533            options = []
 534            while True:
 535                if self._match_text_seq("KEY_BLOCK_SIZE"):
 536                    self._match(TokenType.EQ)
 537                    opt = exp.IndexConstraintOption(key_block_size=self._parse_number())
 538                elif self._match(TokenType.USING):
 539                    opt = exp.IndexConstraintOption(using=self._advance_any() and self._prev.text)
 540                elif self._match_text_seq("WITH", "PARSER"):
 541                    opt = exp.IndexConstraintOption(parser=self._parse_var(any_token=True))
 542                elif self._match(TokenType.COMMENT):
 543                    opt = exp.IndexConstraintOption(comment=self._parse_string())
 544                elif self._match_text_seq("VISIBLE"):
 545                    opt = exp.IndexConstraintOption(visible=True)
 546                elif self._match_text_seq("INVISIBLE"):
 547                    opt = exp.IndexConstraintOption(visible=False)
 548                elif self._match_text_seq("ENGINE_ATTRIBUTE"):
 549                    self._match(TokenType.EQ)
 550                    opt = exp.IndexConstraintOption(engine_attr=self._parse_string())
 551                elif self._match_text_seq("SECONDARY_ENGINE_ATTRIBUTE"):
 552                    self._match(TokenType.EQ)
 553                    opt = exp.IndexConstraintOption(secondary_engine_attr=self._parse_string())
 554                else:
 555                    opt = None
 556
 557                if not opt:
 558                    break
 559
 560                options.append(opt)
 561
 562            return self.expression(
 563                exp.IndexColumnConstraint,
 564                this=this,
 565                expressions=expressions,
 566                kind=kind,
 567                index_type=index_type,
 568                options=options,
 569            )
 570
 571        def _parse_show_mysql(
 572            self,
 573            this: str,
 574            target: bool | str = False,
 575            full: t.Optional[bool] = None,
 576            global_: t.Optional[bool] = None,
 577        ) -> exp.Show:
 578            if target:
 579                if isinstance(target, str):
 580                    self._match_text_seq(target)
 581                target_id = self._parse_id_var()
 582            else:
 583                target_id = None
 584
 585            log = self._parse_string() if self._match_text_seq("IN") else None
 586
 587            if this in ("BINLOG EVENTS", "RELAYLOG EVENTS"):
 588                position = self._parse_number() if self._match_text_seq("FROM") else None
 589                db = None
 590            else:
 591                position = None
 592                db = None
 593
 594                if self._match(TokenType.FROM):
 595                    db = self._parse_id_var()
 596                elif self._match(TokenType.DOT):
 597                    db = target_id
 598                    target_id = self._parse_id_var()
 599
 600            channel = self._parse_id_var() if self._match_text_seq("FOR", "CHANNEL") else None
 601
 602            like = self._parse_string() if self._match_text_seq("LIKE") else None
 603            where = self._parse_where()
 604
 605            if this == "PROFILE":
 606                types = self._parse_csv(lambda: self._parse_var_from_options(self.PROFILE_TYPES))
 607                query = self._parse_number() if self._match_text_seq("FOR", "QUERY") else None
 608                offset = self._parse_number() if self._match_text_seq("OFFSET") else None
 609                limit = self._parse_number() if self._match_text_seq("LIMIT") else None
 610            else:
 611                types, query = None, None
 612                offset, limit = self._parse_oldstyle_limit()
 613
 614            mutex = True if self._match_text_seq("MUTEX") else None
 615            mutex = False if self._match_text_seq("STATUS") else mutex
 616
 617            return self.expression(
 618                exp.Show,
 619                this=this,
 620                target=target_id,
 621                full=full,
 622                log=log,
 623                position=position,
 624                db=db,
 625                channel=channel,
 626                like=like,
 627                where=where,
 628                types=types,
 629                query=query,
 630                offset=offset,
 631                limit=limit,
 632                mutex=mutex,
 633                **{"global": global_},  # type: ignore
 634            )
 635
 636        def _parse_oldstyle_limit(
 637            self,
 638        ) -> t.Tuple[t.Optional[exp.Expression], t.Optional[exp.Expression]]:
 639            limit = None
 640            offset = None
 641            if self._match_text_seq("LIMIT"):
 642                parts = self._parse_csv(self._parse_number)
 643                if len(parts) == 1:
 644                    limit = parts[0]
 645                elif len(parts) == 2:
 646                    limit = parts[1]
 647                    offset = parts[0]
 648
 649            return offset, limit
 650
 651        def _parse_set_item_charset(self, kind: str) -> exp.Expression:
 652            this = self._parse_string() or self._parse_unquoted_field()
 653            return self.expression(exp.SetItem, this=this, kind=kind)
 654
 655        def _parse_set_item_names(self) -> exp.Expression:
 656            charset = self._parse_string() or self._parse_unquoted_field()
 657            if self._match_text_seq("COLLATE"):
 658                collate = self._parse_string() or self._parse_unquoted_field()
 659            else:
 660                collate = None
 661
 662            return self.expression(exp.SetItem, this=charset, collate=collate, kind="NAMES")
 663
 664        def _parse_type(
 665            self, parse_interval: bool = True, fallback_to_identifier: bool = False
 666        ) -> t.Optional[exp.Expression]:
 667            # mysql binary is special and can work anywhere, even in order by operations
 668            # it operates like a no paren func
 669            if self._match(TokenType.BINARY, advance=False):
 670                data_type = self._parse_types(check_func=True, allow_identifiers=False)
 671
 672                if isinstance(data_type, exp.DataType):
 673                    return self.expression(exp.Cast, this=self._parse_column(), to=data_type)
 674
 675            return super()._parse_type(
 676                parse_interval=parse_interval, fallback_to_identifier=fallback_to_identifier
 677            )
 678
 679        def _parse_group_concat(self) -> t.Optional[exp.Expression]:
 680            def concat_exprs(
 681                node: t.Optional[exp.Expression], exprs: t.List[exp.Expression]
 682            ) -> exp.Expression:
 683                if isinstance(node, exp.Distinct) and len(node.expressions) > 1:
 684                    concat_exprs = [
 685                        self.expression(exp.Concat, expressions=node.expressions, safe=True)
 686                    ]
 687                    node.set("expressions", concat_exprs)
 688                    return node
 689                if len(exprs) == 1:
 690                    return exprs[0]
 691                return self.expression(exp.Concat, expressions=args, safe=True)
 692
 693            args = self._parse_csv(self._parse_lambda)
 694
 695            if args:
 696                order = args[-1] if isinstance(args[-1], exp.Order) else None
 697
 698                if order:
 699                    # Order By is the last (or only) expression in the list and has consumed the 'expr' before it,
 700                    # remove 'expr' from exp.Order and add it back to args
 701                    args[-1] = order.this
 702                    order.set("this", concat_exprs(order.this, args))
 703
 704                this = order or concat_exprs(args[0], args)
 705            else:
 706                this = None
 707
 708            separator = self._parse_field() if self._match(TokenType.SEPARATOR) else None
 709
 710            return self.expression(exp.GroupConcat, this=this, separator=separator)
 711
 712        def _parse_alter_table_alter_index(self) -> exp.AlterIndex:
 713            index = self._parse_field(any_token=True)
 714
 715            if self._match_text_seq("VISIBLE"):
 716                visible = True
 717            elif self._match_text_seq("INVISIBLE"):
 718                visible = False
 719            else:
 720                visible = None
 721
 722            return self.expression(exp.AlterIndex, this=index, visible=visible)
 723
 724    class Generator(generator.Generator):
 725        INTERVAL_ALLOWS_PLURAL_FORM = False
 726        LOCKING_READS_SUPPORTED = True
 727        NULL_ORDERING_SUPPORTED = None
 728        JOIN_HINTS = False
 729        TABLE_HINTS = True
 730        DUPLICATE_KEY_UPDATE_WITH_SET = False
 731        QUERY_HINT_SEP = " "
 732        VALUES_AS_TABLE = False
 733        NVL2_SUPPORTED = False
 734        LAST_DAY_SUPPORTS_DATE_PART = False
 735        JSON_TYPE_REQUIRED_FOR_EXTRACTION = True
 736        JSON_PATH_BRACKETED_KEY_SUPPORTED = False
 737        JSON_KEY_VALUE_PAIR_SEP = ","
 738        SUPPORTS_TO_NUMBER = False
 739        PARSE_JSON_NAME: t.Optional[str] = None
 740        PAD_FILL_PATTERN_IS_REQUIRED = True
 741        WRAP_DERIVED_VALUES = False
 742        VARCHAR_REQUIRES_SIZE = True
 743        SUPPORTS_MEDIAN = False
 744
 745        TRANSFORMS = {
 746            **generator.Generator.TRANSFORMS,
 747            exp.ArrayAgg: rename_func("GROUP_CONCAT"),
 748            exp.CurrentDate: no_paren_current_date_sql,
 749            exp.DateDiff: _remove_ts_or_ds_to_date(
 750                lambda self, e: self.func("DATEDIFF", e.this, e.expression), ("this", "expression")
 751            ),
 752            exp.DateAdd: _remove_ts_or_ds_to_date(date_add_sql("ADD")),
 753            exp.DateStrToDate: datestrtodate_sql,
 754            exp.DateSub: _remove_ts_or_ds_to_date(date_add_sql("SUB")),
 755            exp.DateTrunc: _date_trunc_sql,
 756            exp.Day: _remove_ts_or_ds_to_date(),
 757            exp.DayOfMonth: _remove_ts_or_ds_to_date(rename_func("DAYOFMONTH")),
 758            exp.DayOfWeek: _remove_ts_or_ds_to_date(rename_func("DAYOFWEEK")),
 759            exp.DayOfYear: _remove_ts_or_ds_to_date(rename_func("DAYOFYEAR")),
 760            exp.GroupConcat: lambda self,
 761            e: f"""GROUP_CONCAT({self.sql(e, "this")} SEPARATOR {self.sql(e, "separator") or "','"})""",
 762            exp.ILike: no_ilike_sql,
 763            exp.JSONExtractScalar: arrow_json_extract_sql,
 764            exp.Length: length_or_char_length_sql,
 765            exp.LogicalOr: rename_func("MAX"),
 766            exp.LogicalAnd: rename_func("MIN"),
 767            exp.Max: max_or_greatest,
 768            exp.Min: min_or_least,
 769            exp.Month: _remove_ts_or_ds_to_date(),
 770            exp.NullSafeEQ: lambda self, e: self.binary(e, "<=>"),
 771            exp.NullSafeNEQ: lambda self, e: f"NOT {self.binary(e, '<=>')}",
 772            exp.NumberToStr: rename_func("FORMAT"),
 773            exp.Pivot: no_pivot_sql,
 774            exp.Select: transforms.preprocess(
 775                [
 776                    transforms.eliminate_distinct_on,
 777                    transforms.eliminate_semi_and_anti_joins,
 778                    transforms.eliminate_qualify,
 779                    transforms.eliminate_full_outer_join,
 780                    transforms.unnest_generate_date_array_using_recursive_cte,
 781                ]
 782            ),
 783            exp.StrPosition: lambda self, e: strposition_sql(
 784                self, e, func_name="LOCATE", supports_position=True
 785            ),
 786            exp.StrToDate: _str_to_date_sql,
 787            exp.StrToTime: _str_to_date_sql,
 788            exp.Stuff: rename_func("INSERT"),
 789            exp.TableSample: no_tablesample_sql,
 790            exp.TimeFromParts: rename_func("MAKETIME"),
 791            exp.TimestampAdd: date_add_interval_sql("DATE", "ADD"),
 792            exp.TimestampDiff: lambda self, e: self.func(
 793                "TIMESTAMPDIFF", unit_to_var(e), e.expression, e.this
 794            ),
 795            exp.TimestampSub: date_add_interval_sql("DATE", "SUB"),
 796            exp.TimeStrToUnix: rename_func("UNIX_TIMESTAMP"),
 797            exp.TimeStrToTime: lambda self, e: timestrtotime_sql(
 798                self,
 799                e,
 800                include_precision=not e.args.get("zone"),
 801            ),
 802            exp.TimeToStr: _remove_ts_or_ds_to_date(
 803                lambda self, e: self.func("DATE_FORMAT", e.this, self.format_time(e))
 804            ),
 805            exp.Trim: trim_sql,
 806            exp.TryCast: no_trycast_sql,
 807            exp.TsOrDsAdd: date_add_sql("ADD"),
 808            exp.TsOrDsDiff: lambda self, e: self.func("DATEDIFF", e.this, e.expression),
 809            exp.TsOrDsToDate: _ts_or_ds_to_date_sql,
 810            exp.Unicode: lambda self, e: f"ORD(CONVERT({self.sql(e.this)} USING utf32))",
 811            exp.UnixToTime: _unix_to_time_sql,
 812            exp.Week: _remove_ts_or_ds_to_date(),
 813            exp.WeekOfYear: _remove_ts_or_ds_to_date(rename_func("WEEKOFYEAR")),
 814            exp.Year: _remove_ts_or_ds_to_date(),
 815        }
 816
 817        UNSIGNED_TYPE_MAPPING = {
 818            exp.DataType.Type.UBIGINT: "BIGINT",
 819            exp.DataType.Type.UINT: "INT",
 820            exp.DataType.Type.UMEDIUMINT: "MEDIUMINT",
 821            exp.DataType.Type.USMALLINT: "SMALLINT",
 822            exp.DataType.Type.UTINYINT: "TINYINT",
 823            exp.DataType.Type.UDECIMAL: "DECIMAL",
 824            exp.DataType.Type.UDOUBLE: "DOUBLE",
 825        }
 826
 827        TIMESTAMP_TYPE_MAPPING = {
 828            exp.DataType.Type.DATETIME2: "DATETIME",
 829            exp.DataType.Type.SMALLDATETIME: "DATETIME",
 830            exp.DataType.Type.TIMESTAMP: "DATETIME",
 831            exp.DataType.Type.TIMESTAMPNTZ: "DATETIME",
 832            exp.DataType.Type.TIMESTAMPTZ: "TIMESTAMP",
 833            exp.DataType.Type.TIMESTAMPLTZ: "TIMESTAMP",
 834        }
 835
 836        TYPE_MAPPING = {
 837            **generator.Generator.TYPE_MAPPING,
 838            **UNSIGNED_TYPE_MAPPING,
 839            **TIMESTAMP_TYPE_MAPPING,
 840        }
 841
 842        TYPE_MAPPING.pop(exp.DataType.Type.MEDIUMTEXT)
 843        TYPE_MAPPING.pop(exp.DataType.Type.LONGTEXT)
 844        TYPE_MAPPING.pop(exp.DataType.Type.TINYTEXT)
 845        TYPE_MAPPING.pop(exp.DataType.Type.BLOB)
 846        TYPE_MAPPING.pop(exp.DataType.Type.MEDIUMBLOB)
 847        TYPE_MAPPING.pop(exp.DataType.Type.LONGBLOB)
 848        TYPE_MAPPING.pop(exp.DataType.Type.TINYBLOB)
 849
 850        PROPERTIES_LOCATION = {
 851            **generator.Generator.PROPERTIES_LOCATION,
 852            exp.TransientProperty: exp.Properties.Location.UNSUPPORTED,
 853            exp.VolatileProperty: exp.Properties.Location.UNSUPPORTED,
 854        }
 855
 856        LIMIT_FETCH = "LIMIT"
 857
 858        LIMIT_ONLY_LITERALS = True
 859
 860        CHAR_CAST_MAPPING = dict.fromkeys(
 861            (
 862                exp.DataType.Type.LONGTEXT,
 863                exp.DataType.Type.LONGBLOB,
 864                exp.DataType.Type.MEDIUMBLOB,
 865                exp.DataType.Type.MEDIUMTEXT,
 866                exp.DataType.Type.TEXT,
 867                exp.DataType.Type.TINYBLOB,
 868                exp.DataType.Type.TINYTEXT,
 869                exp.DataType.Type.VARCHAR,
 870            ),
 871            "CHAR",
 872        )
 873        SIGNED_CAST_MAPPING = dict.fromkeys(
 874            (
 875                exp.DataType.Type.BIGINT,
 876                exp.DataType.Type.BOOLEAN,
 877                exp.DataType.Type.INT,
 878                exp.DataType.Type.SMALLINT,
 879                exp.DataType.Type.TINYINT,
 880                exp.DataType.Type.MEDIUMINT,
 881            ),
 882            "SIGNED",
 883        )
 884
 885        # MySQL doesn't support many datatypes in cast.
 886        # https://dev.mysql.com/doc/refman/8.0/en/cast-functions.html#function_cast
 887        CAST_MAPPING = {
 888            **CHAR_CAST_MAPPING,
 889            **SIGNED_CAST_MAPPING,
 890            exp.DataType.Type.UBIGINT: "UNSIGNED",
 891        }
 892
 893        TIMESTAMP_FUNC_TYPES = {
 894            exp.DataType.Type.TIMESTAMPTZ,
 895            exp.DataType.Type.TIMESTAMPLTZ,
 896        }
 897
 898        # https://dev.mysql.com/doc/refman/8.0/en/keywords.html
 899        RESERVED_KEYWORDS = {
 900            "accessible",
 901            "add",
 902            "all",
 903            "alter",
 904            "analyze",
 905            "and",
 906            "as",
 907            "asc",
 908            "asensitive",
 909            "before",
 910            "between",
 911            "bigint",
 912            "binary",
 913            "blob",
 914            "both",
 915            "by",
 916            "call",
 917            "cascade",
 918            "case",
 919            "change",
 920            "char",
 921            "character",
 922            "check",
 923            "collate",
 924            "column",
 925            "condition",
 926            "constraint",
 927            "continue",
 928            "convert",
 929            "create",
 930            "cross",
 931            "cube",
 932            "cume_dist",
 933            "current_date",
 934            "current_time",
 935            "current_timestamp",
 936            "current_user",
 937            "cursor",
 938            "database",
 939            "databases",
 940            "day_hour",
 941            "day_microsecond",
 942            "day_minute",
 943            "day_second",
 944            "dec",
 945            "decimal",
 946            "declare",
 947            "default",
 948            "delayed",
 949            "delete",
 950            "dense_rank",
 951            "desc",
 952            "describe",
 953            "deterministic",
 954            "distinct",
 955            "distinctrow",
 956            "div",
 957            "double",
 958            "drop",
 959            "dual",
 960            "each",
 961            "else",
 962            "elseif",
 963            "empty",
 964            "enclosed",
 965            "escaped",
 966            "except",
 967            "exists",
 968            "exit",
 969            "explain",
 970            "false",
 971            "fetch",
 972            "first_value",
 973            "float",
 974            "float4",
 975            "float8",
 976            "for",
 977            "force",
 978            "foreign",
 979            "from",
 980            "fulltext",
 981            "function",
 982            "generated",
 983            "get",
 984            "grant",
 985            "group",
 986            "grouping",
 987            "groups",
 988            "having",
 989            "high_priority",
 990            "hour_microsecond",
 991            "hour_minute",
 992            "hour_second",
 993            "if",
 994            "ignore",
 995            "in",
 996            "index",
 997            "infile",
 998            "inner",
 999            "inout",
1000            "insensitive",
1001            "insert",
1002            "int",
1003            "int1",
1004            "int2",
1005            "int3",
1006            "int4",
1007            "int8",
1008            "integer",
1009            "intersect",
1010            "interval",
1011            "into",
1012            "io_after_gtids",
1013            "io_before_gtids",
1014            "is",
1015            "iterate",
1016            "join",
1017            "json_table",
1018            "key",
1019            "keys",
1020            "kill",
1021            "lag",
1022            "last_value",
1023            "lateral",
1024            "lead",
1025            "leading",
1026            "leave",
1027            "left",
1028            "like",
1029            "limit",
1030            "linear",
1031            "lines",
1032            "load",
1033            "localtime",
1034            "localtimestamp",
1035            "lock",
1036            "long",
1037            "longblob",
1038            "longtext",
1039            "loop",
1040            "low_priority",
1041            "master_bind",
1042            "master_ssl_verify_server_cert",
1043            "match",
1044            "maxvalue",
1045            "mediumblob",
1046            "mediumint",
1047            "mediumtext",
1048            "middleint",
1049            "minute_microsecond",
1050            "minute_second",
1051            "mod",
1052            "modifies",
1053            "natural",
1054            "not",
1055            "no_write_to_binlog",
1056            "nth_value",
1057            "ntile",
1058            "null",
1059            "numeric",
1060            "of",
1061            "on",
1062            "optimize",
1063            "optimizer_costs",
1064            "option",
1065            "optionally",
1066            "or",
1067            "order",
1068            "out",
1069            "outer",
1070            "outfile",
1071            "over",
1072            "partition",
1073            "percent_rank",
1074            "precision",
1075            "primary",
1076            "procedure",
1077            "purge",
1078            "range",
1079            "rank",
1080            "read",
1081            "reads",
1082            "read_write",
1083            "real",
1084            "recursive",
1085            "references",
1086            "regexp",
1087            "release",
1088            "rename",
1089            "repeat",
1090            "replace",
1091            "require",
1092            "resignal",
1093            "restrict",
1094            "return",
1095            "revoke",
1096            "right",
1097            "rlike",
1098            "row",
1099            "rows",
1100            "row_number",
1101            "schema",
1102            "schemas",
1103            "second_microsecond",
1104            "select",
1105            "sensitive",
1106            "separator",
1107            "set",
1108            "show",
1109            "signal",
1110            "smallint",
1111            "spatial",
1112            "specific",
1113            "sql",
1114            "sqlexception",
1115            "sqlstate",
1116            "sqlwarning",
1117            "sql_big_result",
1118            "sql_calc_found_rows",
1119            "sql_small_result",
1120            "ssl",
1121            "starting",
1122            "stored",
1123            "straight_join",
1124            "system",
1125            "table",
1126            "terminated",
1127            "then",
1128            "tinyblob",
1129            "tinyint",
1130            "tinytext",
1131            "to",
1132            "trailing",
1133            "trigger",
1134            "true",
1135            "undo",
1136            "union",
1137            "unique",
1138            "unlock",
1139            "unsigned",
1140            "update",
1141            "usage",
1142            "use",
1143            "using",
1144            "utc_date",
1145            "utc_time",
1146            "utc_timestamp",
1147            "values",
1148            "varbinary",
1149            "varchar",
1150            "varcharacter",
1151            "varying",
1152            "virtual",
1153            "when",
1154            "where",
1155            "while",
1156            "window",
1157            "with",
1158            "write",
1159            "xor",
1160            "year_month",
1161            "zerofill",
1162        }
1163
1164        def computedcolumnconstraint_sql(self, expression: exp.ComputedColumnConstraint) -> str:
1165            persisted = "STORED" if expression.args.get("persisted") else "VIRTUAL"
1166            return f"GENERATED ALWAYS AS ({self.sql(expression.this.unnest())}) {persisted}"
1167
1168        def array_sql(self, expression: exp.Array) -> str:
1169            self.unsupported("Arrays are not supported by MySQL")
1170            return self.function_fallback_sql(expression)
1171
1172        def arraycontainsall_sql(self, expression: exp.ArrayContainsAll) -> str:
1173            self.unsupported("Array operations are not supported by MySQL")
1174            return self.function_fallback_sql(expression)
1175
1176        def dpipe_sql(self, expression: exp.DPipe) -> str:
1177            return self.func("CONCAT", *expression.flatten())
1178
1179        def extract_sql(self, expression: exp.Extract) -> str:
1180            unit = expression.name
1181            if unit and unit.lower() == "epoch":
1182                return self.func("UNIX_TIMESTAMP", expression.expression)
1183
1184            return super().extract_sql(expression)
1185
1186        def datatype_sql(self, expression: exp.DataType) -> str:
1187            if (
1188                self.VARCHAR_REQUIRES_SIZE
1189                and expression.is_type(exp.DataType.Type.VARCHAR)
1190                and not expression.expressions
1191            ):
1192                # `VARCHAR` must always have a size - if it doesn't, we always generate `TEXT`
1193                return "TEXT"
1194
1195            # https://dev.mysql.com/doc/refman/8.0/en/numeric-type-syntax.html
1196            result = super().datatype_sql(expression)
1197            if expression.this in self.UNSIGNED_TYPE_MAPPING:
1198                result = f"{result} UNSIGNED"
1199
1200            return result
1201
1202        def jsonarraycontains_sql(self, expression: exp.JSONArrayContains) -> str:
1203            return f"{self.sql(expression, 'this')} MEMBER OF({self.sql(expression, 'expression')})"
1204
1205        def cast_sql(self, expression: exp.Cast, safe_prefix: t.Optional[str] = None) -> str:
1206            if expression.to.this in self.TIMESTAMP_FUNC_TYPES:
1207                return self.func("TIMESTAMP", expression.this)
1208
1209            to = self.CAST_MAPPING.get(expression.to.this)
1210
1211            if to:
1212                expression.to.set("this", to)
1213            return super().cast_sql(expression)
1214
1215        def show_sql(self, expression: exp.Show) -> str:
1216            this = f" {expression.name}"
1217            full = " FULL" if expression.args.get("full") else ""
1218            global_ = " GLOBAL" if expression.args.get("global") else ""
1219
1220            target = self.sql(expression, "target")
1221            target = f" {target}" if target else ""
1222            if expression.name in ("COLUMNS", "INDEX"):
1223                target = f" FROM{target}"
1224            elif expression.name == "GRANTS":
1225                target = f" FOR{target}"
1226
1227            db = self._prefixed_sql("FROM", expression, "db")
1228
1229            like = self._prefixed_sql("LIKE", expression, "like")
1230            where = self.sql(expression, "where")
1231
1232            types = self.expressions(expression, key="types")
1233            types = f" {types}" if types else types
1234            query = self._prefixed_sql("FOR QUERY", expression, "query")
1235
1236            if expression.name == "PROFILE":
1237                offset = self._prefixed_sql("OFFSET", expression, "offset")
1238                limit = self._prefixed_sql("LIMIT", expression, "limit")
1239            else:
1240                offset = ""
1241                limit = self._oldstyle_limit_sql(expression)
1242
1243            log = self._prefixed_sql("IN", expression, "log")
1244            position = self._prefixed_sql("FROM", expression, "position")
1245
1246            channel = self._prefixed_sql("FOR CHANNEL", expression, "channel")
1247
1248            if expression.name == "ENGINE":
1249                mutex_or_status = " MUTEX" if expression.args.get("mutex") else " STATUS"
1250            else:
1251                mutex_or_status = ""
1252
1253            return f"SHOW{full}{global_}{this}{target}{types}{db}{query}{log}{position}{channel}{mutex_or_status}{like}{where}{offset}{limit}"
1254
1255        def altercolumn_sql(self, expression: exp.AlterColumn) -> str:
1256            dtype = self.sql(expression, "dtype")
1257            if not dtype:
1258                return super().altercolumn_sql(expression)
1259
1260            this = self.sql(expression, "this")
1261            return f"MODIFY COLUMN {this} {dtype}"
1262
1263        def _prefixed_sql(self, prefix: str, expression: exp.Expression, arg: str) -> str:
1264            sql = self.sql(expression, arg)
1265            return f" {prefix} {sql}" if sql else ""
1266
1267        def _oldstyle_limit_sql(self, expression: exp.Show) -> str:
1268            limit = self.sql(expression, "limit")
1269            offset = self.sql(expression, "offset")
1270            if limit:
1271                limit_offset = f"{offset}, {limit}" if offset else limit
1272                return f" LIMIT {limit_offset}"
1273            return ""
1274
1275        def chr_sql(self, expression: exp.Chr) -> str:
1276            this = self.expressions(sqls=[expression.this] + expression.expressions)
1277            charset = expression.args.get("charset")
1278            using = f" USING {self.sql(charset)}" if charset else ""
1279            return f"CHAR({this}{using})"
1280
1281        def timestamptrunc_sql(self, expression: exp.TimestampTrunc) -> str:
1282            unit = expression.args.get("unit")
1283
1284            # Pick an old-enough date to avoid negative timestamp diffs
1285            start_ts = "'0000-01-01 00:00:00'"
1286
1287            # Source: https://stackoverflow.com/a/32955740
1288            timestamp_diff = build_date_delta(exp.TimestampDiff)([unit, start_ts, expression.this])
1289            interval = exp.Interval(this=timestamp_diff, unit=unit)
1290            dateadd = build_date_delta_with_interval(exp.DateAdd)([start_ts, interval])
1291
1292            return self.sql(dateadd)
1293
1294        def converttimezone_sql(self, expression: exp.ConvertTimezone) -> str:
1295            from_tz = expression.args.get("source_tz")
1296            to_tz = expression.args.get("target_tz")
1297            dt = expression.args.get("timestamp")
1298
1299            return self.func("CONVERT_TZ", dt, from_tz, to_tz)
1300
1301        def attimezone_sql(self, expression: exp.AtTimeZone) -> str:
1302            self.unsupported("AT TIME ZONE is not supported by MySQL")
1303            return self.sql(expression.this)
1304
1305        def isascii_sql(self, expression: exp.IsAscii) -> str:
1306            return f"REGEXP_LIKE({self.sql(expression.this)}, '^[[:ascii:]]*$')"
1307
1308        @unsupported_args("this")
1309        def currentschema_sql(self, expression: exp.CurrentSchema) -> str:
1310            return self.func("SCHEMA")