sqlglot.generators.tsql

  1from __future__ import annotations
  2
  3from functools import reduce
  4
  5from sqlglot import exp, generator, transforms
  6from sqlglot.dialects.dialect import (
  7    any_value_to_max_sql,
  8    date_delta_sql,
  9    datestrtodate_sql,
 10    generatedasidentitycolumnconstraint_sql,
 11    max_or_greatest,
 12    min_or_least,
 13    remove_ts_or_ds_to_date,
 14    rename_func,
 15    strposition_sql,
 16    timestrtotime_sql,
 17    trim_sql,
 18)
 19from sqlglot.helper import seq_get
 20from sqlglot.optimizer.scope import find_in_scope
 21from sqlglot.parsers.tsql import OPTIONS_THAT_REQUIRE_EQUAL
 22from sqlglot.time import format_time
 23from collections import defaultdict
 24
 25DATE_PART_UNMAPPING = {
 26    "WEEKISO": "ISO_WEEK",
 27    "DAYOFWEEK": "WEEKDAY",
 28    "TIMEZONE_MINUTE": "TZOFFSET",
 29}
 30
 31BIT_TYPES = {exp.EQ, exp.NEQ, exp.Is, exp.In, exp.Select, exp.Alias}
 32
 33
 34def _format_sql(self: TSQLGenerator, expression: exp.NumberToStr | exp.TimeToStr) -> str:
 35    fmt = expression.args["format"]
 36
 37    if not isinstance(expression, exp.NumberToStr):
 38        if fmt.is_string:
 39            from sqlglot.dialects.tsql import TSQL
 40
 41            mapped_fmt = format_time(fmt.name, TSQL.INVERSE_TIME_MAPPING)
 42            fmt_sql = self.sql(exp.Literal.string(mapped_fmt))
 43        else:
 44            fmt_sql = self.format_time(expression) or self.sql(fmt)
 45    else:
 46        fmt_sql = self.sql(fmt)
 47
 48    return self.func("FORMAT", expression.this, fmt_sql, expression.args.get("culture"))
 49
 50
 51def _string_agg_sql(self: TSQLGenerator, expression: exp.GroupConcat) -> str:
 52    this = expression.this
 53    distinct = find_in_scope(expression, exp.Distinct)
 54    if distinct:
 55        # exp.Distinct can appear below an exp.Order or an exp.GroupConcat expression
 56        self.unsupported("T-SQL STRING_AGG doesn't support DISTINCT.")
 57        this = distinct.pop().expressions[0]
 58
 59    order = ""
 60    if isinstance(expression.this, exp.Order):
 61        if expression.this.this:
 62            this = expression.this.this.pop()
 63        # Order has a leading space
 64        order = f" WITHIN GROUP ({self.sql(expression.this)[1:]})"
 65
 66    separator = expression.args.get("separator") or exp.Literal.string(",")
 67    return f"STRING_AGG({self.format_args(this, separator)}){order}"
 68
 69
 70def qualify_derived_table_outputs(expression: exp.Expr) -> exp.Expr:
 71    """Ensures all (unnamed) output columns are aliased for CTEs and Subqueries."""
 72    alias = expression.args.get("alias")
 73
 74    if (
 75        isinstance(expression, (exp.CTE, exp.Subquery))
 76        and isinstance(alias, exp.TableAlias)
 77        and not alias.columns
 78    ):
 79        from sqlglot.dialects.tsql import TSQL
 80        from sqlglot.optimizer.qualify_columns import qualify_outputs
 81
 82        # We keep track of the unaliased column projection indexes instead of the expressions
 83        # themselves, because the latter are going to be replaced by new nodes when the aliases
 84        # are added and hence we won't be able to reach these newly added Alias parents
 85        query = expression.this
 86        unaliased_column_indexes = (
 87            i for i, c in enumerate(query.selects) if isinstance(c, exp.Column) and not c.alias
 88        )
 89
 90        qualify_outputs(query, dialect=TSQL())
 91
 92        # Preserve the quoting information of columns for newly added Alias nodes
 93        query_selects = query.selects
 94        for select_index in unaliased_column_indexes:
 95            alias = query_selects[select_index]
 96            column = alias.this
 97            if isinstance(column.this, exp.Identifier):
 98                alias.args["alias"].set("quoted", column.this.quoted)
 99
100    return expression
101
102
103def _json_extract_sql(
104    self: TSQLGenerator, expression: exp.JSONExtract | exp.JSONExtractScalar
105) -> str:
106    json_query = self.func("JSON_QUERY", expression.this, expression.expression)
107    json_value = self.func("JSON_VALUE", expression.this, expression.expression)
108    return self.func("ISNULL", json_query, json_value)
109
110
111def _timestrtotime_sql(self: TSQLGenerator, expression: exp.TimeStrToTime):
112    sql = timestrtotime_sql(self, expression)
113    if expression.args.get("zone"):
114        # If there is a timezone, produce an expression like:
115        # CAST('2020-01-01 12:13:14-08:00' AS DATETIMEOFFSET) AT TIME ZONE 'UTC'
116        # If you dont have AT TIME ZONE 'UTC', wrapping that expression in another cast back to DATETIME2 just drops the timezone information
117        return self.sql(exp.AtTimeZone(this=sql, zone=exp.Literal.string("UTC")))
118    return sql
119
120
121class TSQLGenerator(generator.Generator):
122    SELECT_KINDS: tuple[str, ...] = ()
123    TRY_SUPPORTED = False
124    SUPPORTS_UESCAPE = False
125    SUPPORTS_DECODE_CASE = False
126
127    AFTER_HAVING_MODIFIER_TRANSFORMS = generator.AFTER_HAVING_MODIFIER_TRANSFORMS
128
129    LIMIT_IS_TOP = True
130    QUERY_HINTS = False
131    RETURNING_END = False
132    NVL2_SUPPORTED = False
133    ALTER_TABLE_INCLUDE_COLUMN_KEYWORD = False
134    LIMIT_FETCH = "FETCH"
135    COMPUTED_COLUMN_WITH_TYPE = False
136    CTE_RECURSIVE_KEYWORD_REQUIRED = False
137    ENSURE_BOOLS = True
138    NULL_ORDERING_SUPPORTED: bool | None = None
139    SUPPORTS_SINGLE_ARG_CONCAT = False
140    TABLESAMPLE_SEED_KEYWORD = "REPEATABLE"
141    SUPPORTS_SELECT_INTO = True
142    JSON_PATH_BRACKETED_KEY_SUPPORTED = False
143    SUPPORTS_TO_NUMBER = False
144    SET_OP_MODIFIERS = False
145    COPY_PARAMS_EQ_REQUIRED = True
146    PARSE_JSON_NAME: str | None = None
147    EXCEPT_INTERSECT_SUPPORT_ALL_CLAUSE = False
148    ALTER_SET_WRAPPED = True
149    ALTER_SET_TYPE = ""
150
151    EXPRESSIONS_WITHOUT_NESTED_CTES = {
152        exp.Create,
153        exp.Delete,
154        exp.Insert,
155        exp.Intersect,
156        exp.Except,
157        exp.Merge,
158        exp.Select,
159        exp.Subquery,
160        exp.Union,
161        exp.Update,
162    }
163
164    SUPPORTED_JSON_PATH_PARTS = {
165        exp.JSONPathKey,
166        exp.JSONPathRoot,
167        exp.JSONPathSubscript,
168    }
169
170    TYPE_MAPPING = {
171        **{
172            k: v
173            for k, v in generator.Generator.TYPE_MAPPING.items()
174            if k not in (exp.DType.NCHAR, exp.DType.NVARCHAR)
175        },
176        exp.DType.BOOLEAN: "BIT",
177        exp.DType.DATETIME2: "DATETIME2",
178        exp.DType.DECIMAL: "NUMERIC",
179        exp.DType.DOUBLE: "FLOAT",
180        exp.DType.INT: "INTEGER",
181        exp.DType.ROWVERSION: "ROWVERSION",
182        exp.DType.TEXT: "VARCHAR(MAX)",
183        exp.DType.TIMESTAMP: "DATETIME2",
184        exp.DType.TIMESTAMPNTZ: "DATETIME2",
185        exp.DType.TIMESTAMPTZ: "DATETIMEOFFSET",
186        exp.DType.SMALLDATETIME: "SMALLDATETIME",
187        exp.DType.UTINYINT: "TINYINT",
188        exp.DType.VARIANT: "SQL_VARIANT",
189        exp.DType.UUID: "UNIQUEIDENTIFIER",
190    }
191
192    TRANSFORMS = {
193        **{k: v for k, v in generator.Generator.TRANSFORMS.items() if k != exp.ReturnsProperty},
194        exp.AnyValue: any_value_to_max_sql,
195        exp.Atan2: rename_func("ATN2"),
196        exp.ArrayToString: rename_func("STRING_AGG"),
197        exp.AutoIncrementColumnConstraint: lambda *_: "IDENTITY",
198        exp.Ceil: rename_func("CEILING"),
199        exp.Chr: rename_func("CHAR"),
200        exp.DateAdd: date_delta_sql("DATEADD"),
201        exp.CTE: transforms.preprocess([qualify_derived_table_outputs]),
202        exp.CurrentDate: rename_func("GETDATE"),
203        exp.CurrentTimestamp: rename_func("GETDATE"),
204        exp.CurrentTimestampLTZ: rename_func("SYSDATETIMEOFFSET"),
205        exp.DateStrToDate: datestrtodate_sql,
206        exp.Day: remove_ts_or_ds_to_date(),
207        exp.GeneratedAsIdentityColumnConstraint: generatedasidentitycolumnconstraint_sql,
208        exp.GroupConcat: _string_agg_sql,
209        exp.If: rename_func("IIF"),
210        exp.JSONExtract: _json_extract_sql,
211        exp.JSONExtractScalar: _json_extract_sql,
212        exp.LastDay: lambda self, e: self.func("EOMONTH", e.this),
213        exp.Ln: rename_func("LOG"),
214        exp.Max: max_or_greatest,
215        exp.MD5: lambda self, e: self.func("HASHBYTES", exp.Literal.string("MD5"), e.this),
216        exp.Min: min_or_least,
217        exp.Month: remove_ts_or_ds_to_date(),
218        exp.NumberToStr: _format_sql,
219        exp.Repeat: rename_func("REPLICATE"),
220        exp.CurrentSchema: rename_func("SCHEMA_NAME"),
221        exp.Select: transforms.preprocess(
222            [
223                transforms.eliminate_distinct_on,
224                transforms.eliminate_semi_and_anti_joins,
225                transforms.eliminate_qualify,
226                transforms.unnest_generate_date_array_using_recursive_cte,
227            ]
228        ),
229        exp.Stddev: rename_func("STDEV"),
230        exp.StrPosition: lambda self, e: strposition_sql(
231            self, e, func_name="CHARINDEX", supports_position=True
232        ),
233        exp.Subquery: transforms.preprocess([qualify_derived_table_outputs]),
234        exp.SHA: lambda self, e: self.func("HASHBYTES", exp.Literal.string("SHA1"), e.this),
235        exp.SHA1Digest: lambda self, e: self.func("HASHBYTES", exp.Literal.string("SHA1"), e.this),
236        exp.SHA2: lambda self, e: self.func(
237            "HASHBYTES", exp.Literal.string(f"SHA2_{e.args.get('length', 256)}"), e.this
238        ),
239        exp.TemporaryProperty: lambda self, e: "",
240        exp.TimeStrToTime: _timestrtotime_sql,
241        exp.TimeToStr: _format_sql,
242        exp.TimestampAdd: date_delta_sql("DATEADD"),
243        exp.Trim: trim_sql,
244        exp.TsOrDsAdd: date_delta_sql("DATEADD", cast=True),
245        exp.TsOrDsDiff: date_delta_sql("DATEDIFF"),
246        exp.TimestampTrunc: lambda self, e: self.func("DATETRUNC", e.unit, e.this),
247        exp.Trunc: lambda self, e: self.func(
248            "ROUND",
249            e.this,
250            e.args.get("decimals") or exp.Literal.number(0),
251            exp.Literal.number(1),
252        ),
253        exp.Uuid: lambda *_: "NEWID()",
254        exp.Year: remove_ts_or_ds_to_date(),
255        exp.DateFromParts: rename_func("DATEFROMPARTS"),
256    }
257
258    PROPERTIES_LOCATION = {
259        **generator.Generator.PROPERTIES_LOCATION,
260        exp.VolatileProperty: exp.Properties.Location.UNSUPPORTED,
261    }
262
263    def scope_resolution(self, rhs: str, scope_name: str) -> str:
264        return f"{scope_name}::{rhs}"
265
266    def select_sql(self, expression: exp.Select) -> str:
267        limit = expression.args.get("limit")
268        offset = expression.args.get("offset")
269
270        if isinstance(limit, exp.Fetch) and not offset:
271            # Dialects like Oracle can FETCH directly from a row set but
272            # T-SQL requires an ORDER BY + OFFSET clause in order to FETCH
273            offset = exp.Offset(expression=exp.Literal.number(0))
274            expression.set("offset", offset)
275
276        if offset:
277            if not expression.args.get("order"):
278                # ORDER BY is required in order to use OFFSET in a query, so we use
279                # a noop order by, since we don't really care about the order.
280                # See: https://www.microsoftpressstore.com/articles/article.aspx?p=2314819
281                expression.order_by(exp.select(exp.null()).subquery(), copy=False)
282
283            if isinstance(limit, exp.Limit):
284                # TOP and OFFSET can't be combined, we need use FETCH instead of TOP
285                # we replace here because otherwise TOP would be generated in select_sql
286                limit.replace(exp.Fetch(direction="FIRST", count=limit.expression))
287
288        return super().select_sql(expression)
289
290    def convert_sql(self, expression: exp.Convert) -> str:
291        name = "TRY_CONVERT" if expression.args.get("safe") else "CONVERT"
292        return self.func(name, expression.this, expression.expression, expression.args.get("style"))
293
294    def queryoption_sql(self, expression: exp.QueryOption) -> str:
295        option = self.sql(expression, "this")
296        value = self.sql(expression, "expression")
297        if value:
298            optional_equal_sign = "= " if option in OPTIONS_THAT_REQUIRE_EQUAL else ""
299            return f"{option} {optional_equal_sign}{value}"
300        return option
301
302    def lateral_op(self, expression: exp.Lateral) -> str:
303        cross_apply = expression.args.get("cross_apply")
304        if cross_apply is True:
305            return "CROSS APPLY"
306        if cross_apply is False:
307            return "OUTER APPLY"
308
309        # TODO: perhaps we can check if the parent is a Join and transpile it appropriately
310        self.unsupported("LATERAL clause is not supported.")
311        return "LATERAL"
312
313    def splitpart_sql(self, expression: exp.SplitPart) -> str:
314        this = expression.this
315        split_count = len(this.name.split("."))
316        delimiter = expression.args.get("delimiter")
317        part_index = expression.args.get("part_index")
318
319        if (
320            not all(isinstance(arg, exp.Literal) for arg in (this, delimiter, part_index))
321            or (delimiter and delimiter.name != ".")
322            or not part_index
323            or split_count > 4
324        ):
325            self.unsupported(
326                "SPLIT_PART can be transpiled to PARSENAME only for '.' delimiter and literal values"
327            )
328            return ""
329
330        return self.func(
331            "PARSENAME", this, exp.Literal.number(split_count + 1 - part_index.to_py())
332        )
333
334    def extract_sql(self, expression: exp.Extract) -> str:
335        part = expression.this
336        name = DATE_PART_UNMAPPING.get(part.name.upper()) or part
337
338        return self.func("DATEPART", name, expression.expression)
339
340    def timefromparts_sql(self, expression: exp.TimeFromParts) -> str:
341        nano = expression.args.get("nano")
342        if nano is not None:
343            nano.pop()
344            self.unsupported("Specifying nanoseconds is not supported in TIMEFROMPARTS.")
345
346        if expression.args.get("fractions") is None:
347            expression.set("fractions", exp.Literal.number(0))
348        if expression.args.get("precision") is None:
349            expression.set("precision", exp.Literal.number(0))
350
351        return rename_func("TIMEFROMPARTS")(self, expression)
352
353    def timestampfromparts_sql(self, expression: exp.TimestampFromParts) -> str:
354        zone = expression.args.get("zone")
355        if zone is not None:
356            zone.pop()
357            self.unsupported("Time zone is not supported in DATETIMEFROMPARTS.")
358
359        nano = expression.args.get("nano")
360        if nano is not None:
361            nano.pop()
362            self.unsupported("Specifying nanoseconds is not supported in DATETIMEFROMPARTS.")
363
364        if expression.args.get("milli") is None:
365            expression.set("milli", exp.Literal.number(0))
366
367        return rename_func("DATETIMEFROMPARTS")(self, expression)
368
369    def setitem_sql(self, expression: exp.SetItem) -> str:
370        this = expression.this
371        if isinstance(this, exp.EQ) and not isinstance(this.left, exp.Parameter):
372            # T-SQL does not use '=' in SET command, except when the LHS is a variable.
373            return f"{self.sql(this.left)} {self.sql(this.right)}"
374
375        return super().setitem_sql(expression)
376
377    def boolean_sql(self, expression: exp.Boolean) -> str:
378        if type(expression.parent) in BIT_TYPES or isinstance(
379            expression.find_ancestor(exp.Values, exp.Select), exp.Values
380        ):
381            return "1" if expression.this else "0"
382
383        return "(1 = 1)" if expression.this else "(1 = 0)"
384
385    def is_sql(self, expression: exp.Is) -> str:
386        negate = expression.args.get("negate")
387        if isinstance(expression.expression, exp.Boolean):
388            return self.binary(expression, "<>" if negate else "=")
389        return self.binary(expression, "IS NOT" if negate else "IS")
390
391    def createable_sql(self, expression: exp.Create, locations: defaultdict) -> str:
392        sql = self.sql(expression, "this")
393        properties = expression.args.get("properties")
394
395        start = self._identifier_start
396        if (
397            not sql.startswith("#")
398            and not sql.startswith(f"{start}#")
399            and any(
400                isinstance(prop, exp.TemporaryProperty)
401                for prop in (properties.expressions if properties else [])
402            )
403        ):
404            sql = f"{start}#{sql[len(start) :]}" if sql.startswith(start) else f"#{sql}"
405
406        return sql
407
408    def create_sql(self, expression: exp.Create) -> str:
409        kind = expression.kind
410        exists = expression.args.get("exists")
411        expression.set("exists", None)
412
413        like_property = expression.find(exp.LikeProperty)
414        if like_property:
415            ctas_expression = like_property.this
416        else:
417            ctas_expression = expression.expression
418
419        if kind == "VIEW":
420            expression.this.set("catalog", None)
421            with_ = expression.args.get("with_")
422            if ctas_expression and with_:
423                # We've already preprocessed the Create expression to bubble up any nested CTEs,
424                # but CREATE VIEW actually requires the WITH clause to come after it so we need
425                # to amend the AST by moving the CTEs to the CREATE VIEW statement's query.
426                ctas_expression.set("with_", with_.pop())
427        elif (
428            kind == "FUNCTION"
429            and isinstance(ctas_expression, exp.Return)
430            and isinstance(body := ctas_expression.this.unnest(), exp.Query)
431            and (with_ := expression.args.get("with_"))
432        ):
433            # Similar to the VIEW branch, the table-valued functions require the WITH clause
434            # to stay inside the RETURN body, so we move back any CTEs that were bubbled up.
435            body.set("with_", with_.pop())
436
437        table = expression.find(exp.Table)
438
439        # Convert CTAS statement to SELECT .. INTO ..
440        if kind == "TABLE" and ctas_expression:
441            if isinstance(ctas_expression, exp.UNWRAPPED_QUERIES):
442                ctas_expression = ctas_expression.subquery()
443
444            properties = expression.args.get("properties") or exp.Properties()
445            is_temp = any(isinstance(p, exp.TemporaryProperty) for p in properties.expressions)
446
447            select_into = exp.select("*").from_(exp.alias_(ctas_expression, "temp", table=True))
448            select_into.set("into", exp.Into(this=table, temporary=is_temp))
449
450            if like_property:
451                select_into.limit(0, copy=False)
452
453            sql = self.sql(select_into)
454        else:
455            sql = super().create_sql(expression)
456
457        if exists:
458            identifier = self.sql(exp.Literal.string(exp.table_name(table) if table else ""))
459            sql_with_ctes = self.prepend_ctes(expression, sql)
460            sql_literal = self.sql(exp.Literal.string(sql_with_ctes))
461            if kind == "SCHEMA":
462                return f"""IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = {identifier}) EXEC({sql_literal})"""
463            elif kind == "TABLE":
464                assert table
465                where = exp.and_(
466                    exp.column("TABLE_NAME").eq(table.name),
467                    exp.column("TABLE_SCHEMA").eq(table.db) if table.db else None,
468                    exp.column("TABLE_CATALOG").eq(table.catalog) if table.catalog else None,
469                )
470                return f"""IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE {where}) EXEC({sql_literal})"""
471            elif kind == "INDEX":
472                index = self.sql(exp.Literal.string(expression.this.text("this")))
473                return f"""IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = object_id({identifier}) AND name = {index}) EXEC({sql_literal})"""
474        elif expression.args.get("replace"):
475            sql = sql.replace("CREATE OR REPLACE ", "CREATE OR ALTER ", 1)
476
477        return self.prepend_ctes(expression, sql)
478
479    @generator.unsupported_args("unlogged", "expressions")
480    def into_sql(self, expression: exp.Into) -> str:
481        if expression.args.get("temporary"):
482            # If the Into expression has a temporary property, push this down to the Identifier
483            table = expression.find(exp.Table)
484            if table and isinstance(table.this, exp.Identifier):
485                table.this.set("temporary", True)
486
487        return f"{self.seg('INTO')} {self.sql(expression, 'this')}"
488
489    def count_sql(self, expression: exp.Count) -> str:
490        func_name = "COUNT_BIG" if expression.args.get("big_int") else "COUNT"
491        return rename_func(func_name)(self, expression)
492
493    def datediff_sql(self, expression: exp.DateDiff) -> str:
494        func_name = "DATEDIFF_BIG" if expression.args.get("big_int") else "DATEDIFF"
495        return date_delta_sql(func_name)(self, expression)
496
497    def offset_sql(self, expression: exp.Offset) -> str:
498        return f"{super().offset_sql(expression)} ROWS"
499
500    def version_sql(self, expression: exp.Version) -> str:
501        name = "SYSTEM_TIME" if expression.name == "TIMESTAMP" else expression.name
502        this = f"FOR {name}"
503        expr = expression.expression
504        kind = expression.text("kind")
505        if kind in ("FROM", "BETWEEN"):
506            args = expr.expressions
507            sep = "TO" if kind == "FROM" else "AND"
508            expr_sql = f"{self.sql(seq_get(args, 0))} {sep} {self.sql(seq_get(args, 1))}"
509        else:
510            expr_sql = self.sql(expr)
511
512        expr_sql = f" {expr_sql}" if expr_sql else ""
513        return f"{this} {kind}{expr_sql}"
514
515    def returnsproperty_sql(self, expression: exp.ReturnsProperty) -> str:
516        table = expression.args.get("table")
517        table = f"{table} " if table else ""
518        return f"RETURNS {table}{self.sql(expression, 'this')}"
519
520    def returning_sql(self, expression: exp.Returning) -> str:
521        into = self.sql(expression, "into")
522        into = self.seg(f"INTO {into}") if into else ""
523        return f"{self.seg('OUTPUT')} {self.expressions(expression, flat=True)}{into}"
524
525    def transaction_sql(self, expression: exp.Transaction) -> str:
526        this = self.sql(expression, "this")
527        this = f" {this}" if this else ""
528        mark = self.sql(expression, "mark")
529        mark = f" WITH MARK {mark}" if mark else ""
530        return f"BEGIN TRANSACTION{this}{mark}"
531
532    def commit_sql(self, expression: exp.Commit) -> str:
533        this = self.sql(expression, "this")
534        this = f" {this}" if this else ""
535        durability = expression.args.get("durability")
536        durability = (
537            f" WITH (DELAYED_DURABILITY = {'ON' if durability else 'OFF'})"
538            if durability is not None
539            else ""
540        )
541        return f"COMMIT TRANSACTION{this}{durability}"
542
543    def rollback_sql(self, expression: exp.Rollback) -> str:
544        this = self.sql(expression, "this")
545        this = f" {this}" if this else ""
546        return f"ROLLBACK TRANSACTION{this}"
547
548    def identifier_sql(self, expression: exp.Identifier) -> str:
549        identifier = super().identifier_sql(expression)
550
551        if expression.args.get("global_"):
552            prefix = "##"
553        elif expression.args.get("temporary"):
554            prefix = "#"
555        else:
556            return identifier
557
558        start = self._identifier_start
559        if expression.quoted and identifier.startswith(start):
560            return f"{start}{prefix}{identifier[len(start) :]}"
561
562        return f"{prefix}{identifier}"
563
564    def constraint_sql(self, expression: exp.Constraint) -> str:
565        this = self.sql(expression, "this")
566        expressions = self.expressions(expression, flat=True, sep=" ")
567        return f"CONSTRAINT {this} {expressions}"
568
569    def length_sql(self, expression: exp.Length) -> str:
570        return self._uncast_text(expression, "LEN")
571
572    def right_sql(self, expression: exp.Right) -> str:
573        return self._uncast_text(expression, "RIGHT")
574
575    def left_sql(self, expression: exp.Left) -> str:
576        return self._uncast_text(expression, "LEFT")
577
578    def _uncast_text(self, expression: exp.Expr, name: str) -> str:
579        this = expression.this
580        if isinstance(this, exp.Cast) and this.is_type(exp.DType.TEXT):
581            this_sql = self.sql(this, "this")
582        else:
583            this_sql = self.sql(this)
584        expression_sql = self.sql(expression, "expression")
585        return self.func(name, this_sql, expression_sql if expression_sql else None)
586
587    def partition_sql(self, expression: exp.Partition) -> str:
588        return f"WITH (PARTITIONS({self.expressions(expression, flat=True)}))"
589
590    def alter_sql(self, expression: exp.Alter) -> str:
591        action = seq_get(expression.args.get("actions") or [], 0)
592        if isinstance(action, exp.AlterRename):
593            return f"EXEC sp_rename '{self.sql(expression.this)}', '{action.this.name}'"
594        return super().alter_sql(expression)
595
596    def drop_sql(self, expression: exp.Drop) -> str:
597        if expression.args["kind"] == "VIEW":
598            expression.this.set("catalog", None)
599        return super().drop_sql(expression)
600
601    def options_modifier(self, expression: exp.Expr) -> str:
602        options = self.expressions(expression, key="options")
603        return f" OPTION{self.wrap(options)}" if options else ""
604
605    def dpipe_sql(self, expression: exp.DPipe) -> str:
606        return self.sql(reduce(lambda x, y: exp.Add(this=x, expression=y), expression.flatten()))
607
608    def isascii_sql(self, expression: exp.IsAscii) -> str:
609        return f"(PATINDEX(CONVERT(VARCHAR(MAX), 0x255b5e002d7f5d25) COLLATE Latin1_General_BIN, {self.sql(expression.this)}) = 0)"
610
611    def columndef_sql(self, expression: exp.ColumnDef, sep: str = " ") -> str:
612        this = super().columndef_sql(expression, sep)
613        default = self.sql(expression, "default")
614        default = f" = {default}" if default else ""
615        output = self.sql(expression, "output")
616        output = f" {output}" if output else ""
617        return f"{this}{default}{output}"
618
619    def coalesce_sql(self, expression: exp.Coalesce) -> str:
620        func_name = "ISNULL" if expression.args.get("is_null") else "COALESCE"
621        return rename_func(func_name)(self, expression)
622
623    def storedprocedure_sql(self, expression: exp.StoredProcedure) -> str:
624        this = self.sql(expression, "this")
625        expressions = self.expressions(expression)
626        expressions = (
627            self.wrap(expressions) if expression.args.get("wrapped") else f" {expressions}"
628        )
629        return f"{this}{expressions}" if expressions.strip() != "" else this
630
631    def ifblock_sql(self, expression: exp.IfBlock) -> str:
632        this = self.sql(expression, "this")
633        true = self.sql(expression, "true")
634        true = f" {true}" if true else " "
635        false = self.sql(expression, "false")
636        false = f"; ELSE BEGIN {false}" if false else ""
637        return f"IF {this} BEGIN{true}{false}"
638
639    def whileblock_sql(self, expression: exp.WhileBlock) -> str:
640        this = self.sql(expression, "this")
641        body = self.sql(expression, "body")
642        body = f" {body}" if body else " "
643        return f"WHILE {this} BEGIN{body}"
644
645    def execute_sql(self, expression: exp.Execute) -> str:
646        this = self.sql(expression, "this")
647        expressions = self.expressions(expression)
648        expressions = f" {expressions}" if expressions else ""
649        return_status = self.sql(expression, "return_status")
650        return_status = f"{return_status} = " if return_status else ""
651        return f"EXECUTE {return_status}{this}{expressions}"
652
653    def executesql_sql(self, expression: exp.ExecuteSql) -> str:
654        return self.execute_sql(expression)