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    no_filter_sql,
 14    remove_ts_or_ds_to_date,
 15    rename_func,
 16    strposition_sql,
 17    timestrtotime_sql,
 18    trim_sql,
 19)
 20from sqlglot.helper import seq_get
 21from sqlglot.optimizer.scope import find_in_scope
 22from sqlglot.parsers.tsql import OPTIONS_THAT_REQUIRE_EQUAL
 23from sqlglot.time import format_time
 24from collections import defaultdict
 25
 26DATE_PART_UNMAPPING = {
 27    "WEEKISO": "ISO_WEEK",
 28    "DAYOFWEEK": "WEEKDAY",
 29    "TIMEZONE_MINUTE": "TZOFFSET",
 30}
 31
 32BIT_TYPES = {exp.EQ, exp.NEQ, exp.Is, exp.In, exp.Select, exp.Alias}
 33
 34SET_OP_MODIFIERS = ("limit", "offset", "order", "for_", "options")
 35
 36
 37def _format_sql(self: TSQLGenerator, expression: exp.NumberToStr | exp.TimeToStr) -> str:
 38    fmt = expression.args["format"]
 39
 40    if not isinstance(expression, exp.NumberToStr):
 41        if fmt.is_string:
 42            from sqlglot.dialects.tsql import TSQL
 43
 44            mapped_fmt = format_time(fmt.name, TSQL.INVERSE_TIME_MAPPING)
 45            fmt_sql = self.sql(exp.Literal.string(mapped_fmt))
 46        else:
 47            fmt_sql = self.format_time(expression) or self.sql(fmt)
 48    else:
 49        fmt_sql = self.sql(fmt)
 50
 51    return self.func("FORMAT", expression.this, fmt_sql, expression.args.get("culture"))
 52
 53
 54def _string_agg_sql(self: TSQLGenerator, expression: exp.GroupConcat) -> str:
 55    this = expression.this
 56    distinct = find_in_scope(expression, exp.Distinct)
 57    if distinct:
 58        # exp.Distinct can appear below an exp.Order or an exp.GroupConcat expression
 59        self.unsupported("T-SQL STRING_AGG doesn't support DISTINCT.")
 60        this = distinct.pop().expressions[0]
 61
 62    order = ""
 63    if isinstance(expression.this, exp.Order):
 64        if expression.this.this:
 65            this = expression.this.this.pop()
 66        # Order has a leading space
 67        order = f" WITHIN GROUP ({self.sql(expression.this)[1:]})"
 68
 69    separator = expression.args.get("separator") or exp.Literal.string(",")
 70    return f"STRING_AGG({self.format_args(this, separator)}){order}"
 71
 72
 73def qualify_derived_table_outputs(expression: exp.Expr) -> exp.Expr:
 74    """Ensures all (unnamed) output columns are aliased for CTEs and Subqueries."""
 75    alias = expression.args.get("alias")
 76
 77    if (
 78        isinstance(expression, (exp.CTE, exp.Subquery))
 79        and isinstance(alias, exp.TableAlias)
 80        and not alias.columns
 81    ):
 82        from sqlglot.dialects.tsql import TSQL
 83        from sqlglot.optimizer.qualify_columns import qualify_outputs
 84
 85        # We keep track of the unaliased column projection indexes instead of the expressions
 86        # themselves, because the latter are going to be replaced by new nodes when the aliases
 87        # are added and hence we won't be able to reach these newly added Alias parents
 88        query = expression.this
 89        unaliased_column_indexes = (
 90            i for i, c in enumerate(query.selects) if isinstance(c, exp.Column) and not c.alias
 91        )
 92
 93        qualify_outputs(query, dialect=TSQL())
 94
 95        # Preserve the quoting information of columns for newly added Alias nodes
 96        query_selects = query.selects
 97        for select_index in unaliased_column_indexes:
 98            alias = query_selects[select_index]
 99            column = alias.this
100            if isinstance(column.this, exp.Identifier):
101                alias.args["alias"].set("quoted", column.this.quoted)
102
103    return expression
104
105
106def _json_extract_sql(
107    self: TSQLGenerator, expression: exp.JSONExtract | exp.JSONExtractScalar
108) -> str:
109    # JSON_QUERY returns objects and arrays, JSON_VALUE returns scalars. A scalar-only
110    # extraction maps to JSON_VALUE; a source that also returns non-scalar values as
111    # text (e.g. SQLite's ->>) needs to try both, like a generic JSONExtract does
112    if isinstance(expression, exp.JSONExtractScalar) and expression.args.get("scalar_only"):
113        return self.func("JSON_VALUE", expression.this, expression.expression)
114
115    json_query = self.func("JSON_QUERY", expression.this, expression.expression)
116    if expression.args.get("json_query"):
117        return json_query
118
119    json_value = self.func("JSON_VALUE", expression.this, expression.expression)
120    return self.func("ISNULL", json_query, json_value)
121
122
123def _timestrtotime_sql(self: TSQLGenerator, expression: exp.TimeStrToTime):
124    sql = timestrtotime_sql(self, expression)
125    if expression.args.get("zone"):
126        # If there is a timezone, produce an expression like:
127        # CAST('2020-01-01 12:13:14-08:00' AS DATETIMEOFFSET) AT TIME ZONE 'UTC'
128        # If you dont have AT TIME ZONE 'UTC', wrapping that expression in another cast back to DATETIME2 just drops the timezone information
129        return self.sql(exp.AtTimeZone(this=sql, zone=exp.Literal.string("UTC")))
130    return sql
131
132
133class TSQLGenerator(generator.Generator):
134    SELECT_KINDS: tuple[str, ...] = ()
135    TRY_SUPPORTED = False
136    SUPPORTS_UESCAPE = False
137    SUPPORTS_DECODE_CASE = False
138
139    AFTER_HAVING_MODIFIER_TRANSFORMS = generator.AFTER_HAVING_MODIFIER_TRANSFORMS
140
141    LIMIT_IS_TOP = True
142    SET_OP_LIMITS = True
143    QUERY_HINTS = False
144    RETURNING_END = False
145    NVL2_SUPPORTED = False
146    ALTER_TABLE_INCLUDE_COLUMN_KEYWORD = False
147    LIMIT_FETCH = "FETCH"
148    COMPUTED_COLUMN_WITH_TYPE = False
149    CTE_RECURSIVE_KEYWORD_REQUIRED = False
150    ENSURE_BOOLS = True
151    NULL_ORDERING_SUPPORTED: bool | None = None
152    SUPPORTS_SINGLE_ARG_CONCAT = False
153    TABLESAMPLE_SEED_KEYWORD = "REPEATABLE"
154    SUPPORTS_SELECT_INTO = True
155    JSON_PATH_BRACKETED_KEY_SUPPORTED = False
156    SUPPORTS_TO_NUMBER = False
157    COPY_PARAMS_EQ_REQUIRED = True
158    PARSE_JSON_NAME: str | None = None
159    EXCEPT_INTERSECT_SUPPORT_ALL_CLAUSE = False
160    ALTER_SET_WRAPPED = True
161    ALTER_SET_TYPE = ""
162    SUPPORTS_ALTER_COLUMN_NULLABILITY = True
163
164    EXPRESSIONS_WITHOUT_NESTED_CTES = {
165        exp.Create,
166        exp.Delete,
167        exp.Insert,
168        exp.Intersect,
169        exp.Except,
170        exp.Merge,
171        exp.Select,
172        exp.Subquery,
173        exp.Union,
174        exp.Update,
175    }
176
177    SUPPORTED_JSON_PATH_PARTS = {
178        exp.JSONPathKey,
179        exp.JSONPathRoot,
180        exp.JSONPathSubscript,
181    }
182
183    TYPE_MAPPING = {
184        **{
185            k: v
186            for k, v in generator.Generator.TYPE_MAPPING.items()
187            if k not in (exp.DType.NCHAR, exp.DType.NVARCHAR)
188        },
189        exp.DType.BOOLEAN: "BIT",
190        exp.DType.DATETIME2: "DATETIME2",
191        exp.DType.DECIMAL: "NUMERIC",
192        exp.DType.DOUBLE: "FLOAT",
193        exp.DType.INT: "INTEGER",
194        exp.DType.ROWVERSION: "ROWVERSION",
195        exp.DType.TEXT: "VARCHAR(MAX)",
196        exp.DType.TIMESTAMP: "DATETIME2",
197        exp.DType.TIMESTAMPNTZ: "DATETIME2",
198        exp.DType.TIMESTAMPTZ: "DATETIMEOFFSET",
199        exp.DType.SMALLDATETIME: "SMALLDATETIME",
200        exp.DType.UTINYINT: "TINYINT",
201        exp.DType.VARIANT: "SQL_VARIANT",
202        exp.DType.UUID: "UNIQUEIDENTIFIER",
203    }
204
205    TRANSFORMS = {
206        **{k: v for k, v in generator.Generator.TRANSFORMS.items() if k != exp.ReturnsProperty},
207        exp.AnyValue: any_value_to_max_sql,
208        exp.Atan2: rename_func("ATN2"),
209        exp.ArrayToString: rename_func("STRING_AGG"),
210        exp.AutoIncrementColumnConstraint: lambda *_: "IDENTITY",
211        exp.Ceil: rename_func("CEILING"),
212        exp.Chr: rename_func("CHAR"),
213        exp.DateAdd: date_delta_sql("DATEADD"),
214        exp.CTE: transforms.preprocess([qualify_derived_table_outputs]),
215        exp.CurrentDate: rename_func("GETDATE"),
216        exp.CurrentTimestamp: rename_func("GETDATE"),
217        exp.CurrentTimestampLTZ: rename_func("SYSDATETIMEOFFSET"),
218        exp.DateStrToDate: datestrtodate_sql,
219        exp.Day: remove_ts_or_ds_to_date(),
220        exp.Filter: no_filter_sql,
221        exp.GeneratedAsIdentityColumnConstraint: generatedasidentitycolumnconstraint_sql,
222        exp.GroupConcat: _string_agg_sql,
223        exp.If: rename_func("IIF"),
224        exp.JSONExtract: _json_extract_sql,
225        exp.JSONExtractScalar: _json_extract_sql,
226        exp.LastDay: lambda self, e: self.func("EOMONTH", e.this),
227        exp.Ln: rename_func("LOG"),
228        exp.Max: max_or_greatest,
229        exp.MD5: lambda self, e: self.func("HASHBYTES", exp.Literal.string("MD5"), e.this),
230        exp.Min: min_or_least,
231        exp.Month: remove_ts_or_ds_to_date(),
232        exp.NumberToStr: _format_sql,
233        exp.Repeat: rename_func("REPLICATE"),
234        exp.CurrentSchema: rename_func("SCHEMA_NAME"),
235        exp.Select: transforms.preprocess(
236            [
237                transforms.eliminate_distinct_on,
238                transforms.eliminate_semi_and_anti_joins,
239                transforms.eliminate_qualify,
240                transforms.unnest_generate_date_array_using_recursive_cte,
241            ]
242        ),
243        exp.Stddev: rename_func("STDEV"),
244        exp.StrPosition: lambda self, e: strposition_sql(
245            self, e, func_name="CHARINDEX", supports_position=True
246        ),
247        exp.Subquery: transforms.preprocess([qualify_derived_table_outputs]),
248        exp.SHA: lambda self, e: self.func("HASHBYTES", exp.Literal.string("SHA1"), e.this),
249        exp.SHA1Digest: lambda self, e: self.func("HASHBYTES", exp.Literal.string("SHA1"), e.this),
250        exp.SHA2: lambda self, e: self.func(
251            "HASHBYTES", exp.Literal.string(f"SHA2_{e.args.get('length', 256)}"), e.this
252        ),
253        exp.TemporaryProperty: lambda self, e: "",
254        exp.TimeStrToTime: _timestrtotime_sql,
255        exp.TimeToStr: _format_sql,
256        exp.TimestampAdd: date_delta_sql("DATEADD"),
257        exp.Trim: trim_sql,
258        exp.TsOrDsAdd: date_delta_sql("DATEADD", cast=True),
259        exp.TsOrDsDiff: date_delta_sql("DATEDIFF"),
260        exp.TimestampTrunc: lambda self, e: self.func("DATETRUNC", e.unit, e.this),
261        exp.Trunc: lambda self, e: self.func(
262            "ROUND",
263            e.this,
264            e.args.get("decimals") or exp.Literal.number(0),
265            exp.Literal.number(1),
266        ),
267        exp.Uuid: lambda *_: "NEWID()",
268        exp.Year: remove_ts_or_ds_to_date(),
269        exp.DateFromParts: rename_func("DATEFROMPARTS"),
270    }
271
272    PROPERTIES_LOCATION = {
273        **generator.Generator.PROPERTIES_LOCATION,
274        exp.VolatileProperty: exp.Properties.Location.UNSUPPORTED,
275    }
276
277    def scope_resolution(self, rhs: str, scope_name: str) -> str:
278        return f"{scope_name}::{rhs}"
279
280    def select_sql(self, expression: exp.Select) -> str:
281        self._prepare_limit_offset(expression)
282
283        # Handles transpiling a query like the following to T-SQL:
284        #   SELECT 1 AS x ORDER BY x NULLS FIRST FETCH FIRST 1 ROWS ONLY UNION ALL SELECT 2 AS x
285        if isinstance(expression.parent, exp.SetOperation) and isinstance(
286            expression.args.get("limit"), exp.Fetch
287        ):
288            return self.sql(
289                exp.select("*").from_(expression.subquery("_l_0", copy=False), copy=False)
290            )
291
292        return super().select_sql(expression)
293
294    def set_operations(self, expression: exp.SetOperation) -> str:
295        limit = expression.args.get("limit")
296        offset = expression.args.get("offset")
297        order = expression.args.get("order")
298
299        # Set operations cannot order by the CASE used to emulate null ordering,
300        # or by expressions that aren't in their select list.
301        wrap_order = False
302        if order:
303            selects = {select.unalias().unnest() for select in expression.selects}
304            for ordered in order.expressions:
305                this = ordered.this.unnest()
306                if this.is_int:
307                    continue
308
309                desc = ordered.args.get("desc")
310                nulls_first = ordered.args.get("nulls_first")
311
312                emulate_null_ordering = (desc and nulls_first) or (not desc and not nulls_first)
313                if emulate_null_ordering or (
314                    not isinstance(this, exp.Column) and this not in selects
315                ):
316                    wrap_order = True
317                    break
318
319        if (
320            wrap_order
321            or (isinstance(limit, exp.Limit) and not offset)
322            or (not order and (offset or isinstance(limit, exp.Fetch)))
323        ):
324            select = self._move_ctes_to_top_level(
325                exp.subquery(expression, "_l_0", copy=False).select("*", copy=False)
326            )
327            for arg in SET_OP_MODIFIERS:
328                value = expression.args.get(arg)
329                if value:
330                    expression.set(arg, None)
331                    select.set(arg, value)
332
333            return self.sql(select)
334
335        self._prepare_limit_offset(expression)
336        return super().set_operations(expression)
337
338    def _prepare_limit_offset(self, expression: exp.Query) -> None:
339        limit = expression.args.get("limit")
340        offset = expression.args.get("offset")
341
342        if isinstance(limit, exp.Fetch) and not offset:
343            # Dialects like Oracle can FETCH directly from a row set but
344            # T-SQL requires an ORDER BY + OFFSET clause in order to FETCH
345            offset = exp.Offset(expression=exp.Literal.number(0))
346            expression.set("offset", offset)
347
348        if offset:
349            if not expression.args.get("order"):
350                # ORDER BY is required in order to use OFFSET in a query, so we use
351                # a noop order by, since we don't really care about the order.
352                # See: https://www.microsoftpressstore.com/articles/article.aspx?p=2314819
353                expression.order_by(exp.select(exp.null()).subquery(), copy=False)
354
355            if isinstance(limit, exp.Limit) and not limit.is_limit_all:
356                # TOP and OFFSET can't be combined, we need use FETCH instead of TOP
357                # we replace here because otherwise TOP would be generated in select_sql
358                limit.replace(exp.Fetch(direction="FIRST", count=limit.expression))
359
360    def convert_sql(self, expression: exp.Convert) -> str:
361        name = "TRY_CONVERT" if expression.args.get("safe") else "CONVERT"
362        return self.func(name, expression.this, expression.expression, expression.args.get("style"))
363
364    def queryoption_sql(self, expression: exp.QueryOption) -> str:
365        option = self.sql(expression, "this")
366        value = self.sql(expression, "expression")
367        if value:
368            optional_equal_sign = "= " if option in OPTIONS_THAT_REQUIRE_EQUAL else ""
369            return f"{option} {optional_equal_sign}{value}"
370        return option
371
372    def lateral_op(self, expression: exp.Lateral) -> str:
373        cross_apply = expression.args.get("cross_apply")
374        if cross_apply is True:
375            return "CROSS APPLY"
376        if cross_apply is False:
377            return "OUTER APPLY"
378
379        # TODO: perhaps we can check if the parent is a Join and transpile it appropriately
380        self.unsupported("LATERAL clause is not supported.")
381        return "LATERAL"
382
383    def splitpart_sql(self, expression: exp.SplitPart) -> str:
384        this = expression.this
385        split_count = len(this.name.split("."))
386        delimiter = expression.args.get("delimiter")
387        part_index = expression.args.get("part_index")
388
389        if (
390            not all(isinstance(arg, exp.Literal) for arg in (this, delimiter, part_index))
391            or (delimiter and delimiter.name != ".")
392            or not part_index
393            or split_count > 4
394        ):
395            self.unsupported(
396                "SPLIT_PART can be transpiled to PARSENAME only for '.' delimiter and literal values"
397            )
398            return ""
399
400        return self.func(
401            "PARSENAME", this, exp.Literal.number(split_count + 1 - part_index.to_py())
402        )
403
404    def extract_sql(self, expression: exp.Extract) -> str:
405        part = expression.this
406        name = DATE_PART_UNMAPPING.get(part.name.upper()) or part
407
408        return self.func("DATEPART", name, expression.expression)
409
410    def timefromparts_sql(self, expression: exp.TimeFromParts) -> str:
411        nano = expression.args.get("nano")
412        if nano is not None:
413            nano.pop()
414            self.unsupported("Specifying nanoseconds is not supported in TIMEFROMPARTS.")
415
416        if expression.args.get("fractions") is None:
417            expression.set("fractions", exp.Literal.number(0))
418        if expression.args.get("precision") is None:
419            expression.set("precision", exp.Literal.number(0))
420
421        return rename_func("TIMEFROMPARTS")(self, expression)
422
423    def timestampfromparts_sql(self, expression: exp.TimestampFromParts) -> str:
424        zone = expression.args.get("zone")
425        if zone is not None:
426            zone.pop()
427            self.unsupported("Time zone is not supported in DATETIMEFROMPARTS.")
428
429        nano = expression.args.get("nano")
430        if nano is not None:
431            nano.pop()
432            self.unsupported("Specifying nanoseconds is not supported in DATETIMEFROMPARTS.")
433
434        if expression.args.get("milli") is None:
435            expression.set("milli", exp.Literal.number(0))
436
437        return rename_func("DATETIMEFROMPARTS")(self, expression)
438
439    def setitem_sql(self, expression: exp.SetItem) -> str:
440        this = expression.this
441        if isinstance(this, exp.EQ) and not isinstance(this.left, exp.Parameter):
442            # T-SQL does not use '=' in SET command, except when the LHS is a variable.
443            return f"{self.sql(this.left)} {self.sql(this.right)}"
444
445        return super().setitem_sql(expression)
446
447    def boolean_sql(self, expression: exp.Boolean) -> str:
448        if type(expression.parent) in BIT_TYPES or isinstance(
449            expression.find_ancestor(exp.Values, exp.Select), exp.Values
450        ):
451            return "1" if expression.this else "0"
452
453        return "(1 = 1)" if expression.this else "(1 = 0)"
454
455    def is_sql(self, expression: exp.Is) -> str:
456        negate = expression.args.get("negate")
457        if isinstance(expression.expression, exp.Boolean):
458            return self.binary(expression, "<>" if negate else "=")
459        return self.binary(expression, "IS NOT" if negate else "IS")
460
461    def createable_sql(self, expression: exp.Create, locations: defaultdict) -> str:
462        sql = self.sql(expression, "this")
463        properties = expression.args.get("properties")
464
465        start = self._identifier_start
466        if (
467            not sql.startswith("#")
468            and not sql.startswith(f"{start}#")
469            and any(
470                isinstance(prop, exp.TemporaryProperty)
471                for prop in (properties.expressions if properties else [])
472            )
473        ):
474            sql = f"{start}#{sql[len(start) :]}" if sql.startswith(start) else f"#{sql}"
475
476        return sql
477
478    def create_sql(self, expression: exp.Create) -> str:
479        kind = expression.kind
480        exists = expression.args.get("exists")
481        expression.set("exists", None)
482
483        like_property = expression.find(exp.LikeProperty)
484        if like_property:
485            ctas_expression = like_property.this
486        else:
487            ctas_expression = expression.expression
488
489        if kind == "VIEW":
490            expression.this.set("catalog", None)
491            with_ = expression.args.get("with_")
492            if ctas_expression and with_:
493                # We've already preprocessed the Create expression to bubble up any nested CTEs,
494                # but CREATE VIEW actually requires the WITH clause to come after it so we need
495                # to amend the AST by moving the CTEs to the CREATE VIEW statement's query.
496                ctas_expression.set("with_", with_.pop())
497        elif (
498            kind == "FUNCTION"
499            and isinstance(ctas_expression, exp.Return)
500            and isinstance(body := ctas_expression.this.unnest(), exp.Query)
501            and (with_ := expression.args.get("with_"))
502        ):
503            # Similar to the VIEW branch, the table-valued functions require the WITH clause
504            # to stay inside the RETURN body, so we move back any CTEs that were bubbled up.
505            body.set("with_", with_.pop())
506
507        table = expression.find(exp.Table)
508
509        # Convert CTAS statement to SELECT .. INTO ..
510        if kind == "TABLE" and ctas_expression:
511            if isinstance(ctas_expression, exp.UNWRAPPED_QUERIES):
512                ctas_expression = ctas_expression.subquery()
513
514            properties = expression.args.get("properties") or exp.Properties()
515            is_temp = any(isinstance(p, exp.TemporaryProperty) for p in properties.expressions)
516
517            select_into = exp.select("*").from_(exp.alias_(ctas_expression, "temp", table=True))
518            select_into.set("into", exp.Into(this=table, temporary=is_temp))
519
520            if like_property:
521                select_into.limit(0, copy=False)
522
523            sql = self.sql(select_into)
524        else:
525            sql = super().create_sql(expression)
526
527        if exists:
528            identifier = self.sql(exp.Literal.string(exp.table_name(table) if table else ""))
529            sql_with_ctes = self.prepend_ctes(expression, sql)
530            sql_literal = self.sql(exp.Literal.string(sql_with_ctes))
531            if kind == "SCHEMA":
532                return f"""IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = {identifier}) EXEC({sql_literal})"""
533            elif kind == "TABLE":
534                assert table
535                where = exp.and_(
536                    exp.column("TABLE_NAME").eq(table.name),
537                    exp.column("TABLE_SCHEMA").eq(table.db) if table.db else None,
538                    exp.column("TABLE_CATALOG").eq(table.catalog) if table.catalog else None,
539                )
540                return f"""IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE {where}) EXEC({sql_literal})"""
541            elif kind == "INDEX":
542                index = self.sql(exp.Literal.string(expression.this.text("this")))
543                return f"""IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = object_id({identifier}) AND name = {index}) EXEC({sql_literal})"""
544        elif expression.args.get("replace"):
545            sql = sql.replace("CREATE OR REPLACE ", "CREATE OR ALTER ", 1)
546
547        return self.prepend_ctes(expression, sql)
548
549    @generator.unsupported_args("unlogged", "expressions")
550    def into_sql(self, expression: exp.Into) -> str:
551        if expression.args.get("temporary"):
552            # If the Into expression has a temporary property, push this down to the Identifier
553            table = expression.find(exp.Table)
554            if table and isinstance(table.this, exp.Identifier):
555                table.this.set("temporary", True)
556
557        return f"{self.seg('INTO')} {self.sql(expression, 'this')}"
558
559    def count_sql(self, expression: exp.Count) -> str:
560        func_name = "COUNT_BIG" if expression.args.get("big_int") else "COUNT"
561        return rename_func(func_name)(self, expression)
562
563    def countif_sql(self, expression: exp.CountIf) -> str:
564        # T-SQL has no COUNT_IF, so count the rows where the predicate holds instead
565        return self.func(
566            "COUNT", exp.If(this=expression.this, true=exp.Literal.number(1), false=exp.null())
567        )
568
569    def datediff_sql(self, expression: exp.DateDiff) -> str:
570        func_name = "DATEDIFF_BIG" if expression.args.get("big_int") else "DATEDIFF"
571        return date_delta_sql(func_name)(self, expression)
572
573    def offset_sql(self, expression: exp.Offset) -> str:
574        return f"{super().offset_sql(expression)} ROWS"
575
576    def version_sql(self, expression: exp.Version) -> str:
577        name = "SYSTEM_TIME" if expression.name == "TIMESTAMP" else expression.name
578        this = f"FOR {name}"
579        expr = expression.expression
580        kind = expression.text("kind")
581        if kind in ("FROM", "BETWEEN"):
582            args = expr.expressions
583            sep = "TO" if kind == "FROM" else "AND"
584            expr_sql = f"{self.sql(seq_get(args, 0))} {sep} {self.sql(seq_get(args, 1))}"
585        else:
586            expr_sql = self.sql(expr)
587
588        expr_sql = f" {expr_sql}" if expr_sql else ""
589        return f"{this} {kind}{expr_sql}"
590
591    def returnsproperty_sql(self, expression: exp.ReturnsProperty) -> str:
592        table = expression.args.get("table")
593        table = f"{table} " if table else ""
594        return f"RETURNS {table}{self.sql(expression, 'this')}"
595
596    def returning_sql(self, expression: exp.Returning) -> str:
597        into = self.sql(expression, "into")
598        into = self.seg(f"INTO {into}") if into else ""
599        return f"{self.seg('OUTPUT')} {self.expressions(expression, flat=True)}{into}"
600
601    def transaction_sql(self, expression: exp.Transaction) -> str:
602        this = self.sql(expression, "this")
603        this = f" {this}" if this else ""
604        mark = self.sql(expression, "mark")
605        mark = f" WITH MARK {mark}" if mark else ""
606        return f"BEGIN TRANSACTION{this}{mark}"
607
608    def commit_sql(self, expression: exp.Commit) -> str:
609        this = self.sql(expression, "this")
610        this = f" {this}" if this else ""
611        durability = expression.args.get("durability")
612        durability = (
613            f" WITH (DELAYED_DURABILITY = {'ON' if durability else 'OFF'})"
614            if durability is not None
615            else ""
616        )
617        return f"COMMIT TRANSACTION{this}{durability}"
618
619    def rollback_sql(self, expression: exp.Rollback) -> str:
620        this = self.sql(expression, "this")
621        this = f" {this}" if this else ""
622        return f"ROLLBACK TRANSACTION{this}"
623
624    def identifier_sql(self, expression: exp.Identifier) -> str:
625        identifier = super().identifier_sql(expression)
626
627        if expression.args.get("global_"):
628            prefix = "##"
629        elif expression.args.get("temporary"):
630            prefix = "#"
631        else:
632            return identifier
633
634        start = self._identifier_start
635        if expression.quoted and identifier.startswith(start):
636            return f"{start}{prefix}{identifier[len(start) :]}"
637
638        return f"{prefix}{identifier}"
639
640    def constraint_sql(self, expression: exp.Constraint) -> str:
641        this = self.sql(expression, "this")
642        expressions = self.expressions(expression, flat=True, sep=" ")
643        return f"CONSTRAINT {this} {expressions}"
644
645    def length_sql(self, expression: exp.Length) -> str:
646        return self._uncast_text(expression, "LEN")
647
648    def right_sql(self, expression: exp.Right) -> str:
649        return self._uncast_text(expression, "RIGHT")
650
651    def left_sql(self, expression: exp.Left) -> str:
652        return self._uncast_text(expression, "LEFT")
653
654    def _uncast_text(self, expression: exp.Expr, name: str) -> str:
655        this = expression.this
656        if isinstance(this, exp.Cast) and this.is_type(exp.DType.TEXT):
657            this_sql = self.sql(this, "this")
658        else:
659            this_sql = self.sql(this)
660        expression_sql = self.sql(expression, "expression")
661        return self.func(name, this_sql, expression_sql if expression_sql else None)
662
663    def partition_sql(self, expression: exp.Partition) -> str:
664        return f"WITH (PARTITIONS({self.expressions(expression, flat=True)}))"
665
666    def alter_sql(self, expression: exp.Alter) -> str:
667        actions = expression.args.get("actions") or []
668        if len(actions) == 1 and isinstance(actions[0], exp.AlterRename):
669            return f"EXEC sp_rename '{self.sql(expression.this)}', '{actions[0].this.name}'"
670        return super().alter_sql(expression)
671
672    def drop_sql(self, expression: exp.Drop) -> str:
673        if expression.args["kind"] == "VIEW":
674            for table in expression.args.get("tables") or []:
675                table.set("catalog", None)
676        return super().drop_sql(expression)
677
678    def options_modifier(self, expression: exp.Expr) -> str:
679        options = self.expressions(expression, key="options")
680        return f" OPTION{self.wrap(options)}" if options else ""
681
682    def dpipe_sql(self, expression: exp.DPipe) -> str:
683        return self.sql(reduce(lambda x, y: exp.Add(this=x, expression=y), expression.flatten()))
684
685    def isascii_sql(self, expression: exp.IsAscii) -> str:
686        return f"(PATINDEX(CONVERT(VARCHAR(MAX), 0x255b5e002d7f5d25) COLLATE Latin1_General_BIN, {self.sql(expression.this)}) = 0)"
687
688    def columndef_sql(self, expression: exp.ColumnDef, sep: str = " ") -> str:
689        this = super().columndef_sql(expression, sep)
690        default = self.sql(expression, "default")
691        default = f" = {default}" if default else ""
692        output = self.sql(expression, "output")
693        output = f" {output}" if output else ""
694        return f"{this}{default}{output}"
695
696    def coalesce_sql(self, expression: exp.Coalesce) -> str:
697        func_name = "ISNULL" if expression.args.get("is_null") else "COALESCE"
698        return rename_func(func_name)(self, expression)
699
700    def storedprocedure_sql(self, expression: exp.StoredProcedure) -> str:
701        this = self.sql(expression, "this")
702        expressions = self.expressions(expression)
703        expressions = (
704            self.wrap(expressions) if expression.args.get("wrapped") else f" {expressions}"
705        )
706        return f"{this}{expressions}" if expressions.strip() != "" else this
707
708    def ifblock_sql(self, expression: exp.IfBlock) -> str:
709        this = self.sql(expression, "this")
710        true = self.sql(expression, "true")
711        true = f" {true}" if true else " "
712        false = self.sql(expression, "false")
713        false = f"; ELSE BEGIN {false}" if false else ""
714        return f"IF {this} BEGIN{true}{false}"
715
716    def whileblock_sql(self, expression: exp.WhileBlock) -> str:
717        this = self.sql(expression, "this")
718        body = self.sql(expression, "body")
719        body = f" {body}" if body else " "
720        return f"WHILE {this} BEGIN{body}"
721
722    def execute_sql(self, expression: exp.Execute) -> str:
723        this = self.sql(expression, "this")
724        expressions = self.expressions(expression)
725        expressions = f" {expressions}" if expressions else ""
726        return_status = self.sql(expression, "return_status")
727        return_status = f"{return_status} = " if return_status else ""
728        return f"EXECUTE {return_status}{this}{expressions}"
729
730    def executesql_sql(self, expression: exp.ExecuteSql) -> str:
731        return self.execute_sql(expression)