sqlglot.dialects.dialect

  1from __future__ import annotations
  2
  3import typing as t
  4from enum import Enum
  5from functools import reduce
  6
  7from sqlglot import exp
  8from sqlglot._typing import E
  9from sqlglot.errors import ParseError
 10from sqlglot.generator import Generator
 11from sqlglot.helper import flatten, seq_get
 12from sqlglot.parser import Parser
 13from sqlglot.time import TIMEZONES, format_time
 14from sqlglot.tokens import Token, Tokenizer, TokenType
 15from sqlglot.trie import new_trie
 16
 17B = t.TypeVar("B", bound=exp.Binary)
 18
 19
 20class Dialects(str, Enum):
 21    DIALECT = ""
 22
 23    BIGQUERY = "bigquery"
 24    CLICKHOUSE = "clickhouse"
 25    DATABRICKS = "databricks"
 26    DRILL = "drill"
 27    DUCKDB = "duckdb"
 28    HIVE = "hive"
 29    MYSQL = "mysql"
 30    ORACLE = "oracle"
 31    POSTGRES = "postgres"
 32    PRESTO = "presto"
 33    REDSHIFT = "redshift"
 34    SNOWFLAKE = "snowflake"
 35    SPARK = "spark"
 36    SPARK2 = "spark2"
 37    SQLITE = "sqlite"
 38    STARROCKS = "starrocks"
 39    TABLEAU = "tableau"
 40    TERADATA = "teradata"
 41    TRINO = "trino"
 42    TSQL = "tsql"
 43    Doris = "doris"
 44
 45
 46class _Dialect(type):
 47    classes: t.Dict[str, t.Type[Dialect]] = {}
 48
 49    def __eq__(cls, other: t.Any) -> bool:
 50        if cls is other:
 51            return True
 52        if isinstance(other, str):
 53            return cls is cls.get(other)
 54        if isinstance(other, Dialect):
 55            return cls is type(other)
 56
 57        return False
 58
 59    def __hash__(cls) -> int:
 60        return hash(cls.__name__.lower())
 61
 62    @classmethod
 63    def __getitem__(cls, key: str) -> t.Type[Dialect]:
 64        return cls.classes[key]
 65
 66    @classmethod
 67    def get(
 68        cls, key: str, default: t.Optional[t.Type[Dialect]] = None
 69    ) -> t.Optional[t.Type[Dialect]]:
 70        return cls.classes.get(key, default)
 71
 72    def __new__(cls, clsname, bases, attrs):
 73        klass = super().__new__(cls, clsname, bases, attrs)
 74        enum = Dialects.__members__.get(clsname.upper())
 75        cls.classes[enum.value if enum is not None else clsname.lower()] = klass
 76
 77        klass.TIME_TRIE = new_trie(klass.TIME_MAPPING)
 78        klass.FORMAT_TRIE = (
 79            new_trie(klass.FORMAT_MAPPING) if klass.FORMAT_MAPPING else klass.TIME_TRIE
 80        )
 81        klass.INVERSE_TIME_MAPPING = {v: k for k, v in klass.TIME_MAPPING.items()}
 82        klass.INVERSE_TIME_TRIE = new_trie(klass.INVERSE_TIME_MAPPING)
 83
 84        klass.INVERSE_ESCAPE_SEQUENCES = {v: k for k, v in klass.ESCAPE_SEQUENCES.items()}
 85
 86        klass.tokenizer_class = getattr(klass, "Tokenizer", Tokenizer)
 87        klass.parser_class = getattr(klass, "Parser", Parser)
 88        klass.generator_class = getattr(klass, "Generator", Generator)
 89
 90        klass.QUOTE_START, klass.QUOTE_END = list(klass.tokenizer_class._QUOTES.items())[0]
 91        klass.IDENTIFIER_START, klass.IDENTIFIER_END = list(
 92            klass.tokenizer_class._IDENTIFIERS.items()
 93        )[0]
 94
 95        def get_start_end(token_type: TokenType) -> t.Tuple[t.Optional[str], t.Optional[str]]:
 96            return next(
 97                (
 98                    (s, e)
 99                    for s, (e, t) in klass.tokenizer_class._FORMAT_STRINGS.items()
100                    if t == token_type
101                ),
102                (None, None),
103            )
104
105        klass.BIT_START, klass.BIT_END = get_start_end(TokenType.BIT_STRING)
106        klass.HEX_START, klass.HEX_END = get_start_end(TokenType.HEX_STRING)
107        klass.BYTE_START, klass.BYTE_END = get_start_end(TokenType.BYTE_STRING)
108
109        dialect_properties = {
110            **{
111                k: v
112                for k, v in vars(klass).items()
113                if not callable(v) and not isinstance(v, classmethod) and not k.startswith("__")
114            },
115            "TOKENIZER_CLASS": klass.tokenizer_class,
116        }
117
118        if enum not in ("", "bigquery"):
119            dialect_properties["SELECT_KINDS"] = ()
120
121        # Pass required dialect properties to the tokenizer, parser and generator classes
122        for subclass in (klass.tokenizer_class, klass.parser_class, klass.generator_class):
123            for name, value in dialect_properties.items():
124                if hasattr(subclass, name):
125                    setattr(subclass, name, value)
126
127        if not klass.STRICT_STRING_CONCAT and klass.DPIPE_IS_STRING_CONCAT:
128            klass.parser_class.BITWISE[TokenType.DPIPE] = exp.SafeDPipe
129
130        if not klass.SUPPORTS_SEMI_ANTI_JOIN:
131            klass.parser_class.TABLE_ALIAS_TOKENS = klass.parser_class.TABLE_ALIAS_TOKENS | {
132                TokenType.ANTI,
133                TokenType.SEMI,
134            }
135
136        klass.generator_class.can_identify = klass.can_identify
137
138        return klass
139
140
141class Dialect(metaclass=_Dialect):
142    # Determines the base index offset for arrays
143    INDEX_OFFSET = 0
144
145    # If true unnest table aliases are considered only as column aliases
146    UNNEST_COLUMN_ONLY = False
147
148    # Determines whether or not the table alias comes after tablesample
149    ALIAS_POST_TABLESAMPLE = False
150
151    # Determines whether or not unquoted identifiers are resolved as uppercase
152    # When set to None, it means that the dialect treats all identifiers as case-insensitive
153    RESOLVES_IDENTIFIERS_AS_UPPERCASE: t.Optional[bool] = False
154
155    # Determines whether or not an unquoted identifier can start with a digit
156    IDENTIFIERS_CAN_START_WITH_DIGIT = False
157
158    # Determines whether or not the DPIPE token ('||') is a string concatenation operator
159    DPIPE_IS_STRING_CONCAT = True
160
161    # Determines whether or not CONCAT's arguments must be strings
162    STRICT_STRING_CONCAT = False
163
164    # Determines whether or not user-defined data types are supported
165    SUPPORTS_USER_DEFINED_TYPES = True
166
167    # Determines whether or not SEMI/ANTI JOINs are supported
168    SUPPORTS_SEMI_ANTI_JOIN = True
169
170    # Determines how function names are going to be normalized
171    NORMALIZE_FUNCTIONS: bool | str = "upper"
172
173    # Determines whether the base comes first in the LOG function
174    LOG_BASE_FIRST = True
175
176    # Indicates the default null ordering method to use if not explicitly set
177    # Options are: "nulls_are_small", "nulls_are_large", "nulls_are_last"
178    NULL_ORDERING = "nulls_are_small"
179
180    DATE_FORMAT = "'%Y-%m-%d'"
181    DATEINT_FORMAT = "'%Y%m%d'"
182    TIME_FORMAT = "'%Y-%m-%d %H:%M:%S'"
183
184    # Custom time mappings in which the key represents dialect time format
185    # and the value represents a python time format
186    TIME_MAPPING: t.Dict[str, str] = {}
187
188    # https://cloud.google.com/bigquery/docs/reference/standard-sql/format-elements#format_model_rules_date_time
189    # https://docs.teradata.com/r/Teradata-Database-SQL-Functions-Operators-Expressions-and-Predicates/March-2017/Data-Type-Conversions/Character-to-DATE-Conversion/Forcing-a-FORMAT-on-CAST-for-Converting-Character-to-DATE
190    # special syntax cast(x as date format 'yyyy') defaults to time_mapping
191    FORMAT_MAPPING: t.Dict[str, str] = {}
192
193    # Mapping of an unescaped escape sequence to the corresponding character
194    ESCAPE_SEQUENCES: t.Dict[str, str] = {}
195
196    # Columns that are auto-generated by the engine corresponding to this dialect
197    # Such columns may be excluded from SELECT * queries, for example
198    PSEUDOCOLUMNS: t.Set[str] = set()
199
200    # Autofilled
201    tokenizer_class = Tokenizer
202    parser_class = Parser
203    generator_class = Generator
204
205    # A trie of the time_mapping keys
206    TIME_TRIE: t.Dict = {}
207    FORMAT_TRIE: t.Dict = {}
208
209    INVERSE_TIME_MAPPING: t.Dict[str, str] = {}
210    INVERSE_TIME_TRIE: t.Dict = {}
211
212    INVERSE_ESCAPE_SEQUENCES: t.Dict[str, str] = {}
213
214    def __eq__(self, other: t.Any) -> bool:
215        return type(self) == other
216
217    def __hash__(self) -> int:
218        return hash(type(self))
219
220    @classmethod
221    def get_or_raise(cls, dialect: DialectType) -> t.Type[Dialect]:
222        if not dialect:
223            return cls
224        if isinstance(dialect, _Dialect):
225            return dialect
226        if isinstance(dialect, Dialect):
227            return dialect.__class__
228
229        result = cls.get(dialect)
230        if not result:
231            raise ValueError(f"Unknown dialect '{dialect}'")
232
233        return result
234
235    @classmethod
236    def format_time(
237        cls, expression: t.Optional[str | exp.Expression]
238    ) -> t.Optional[exp.Expression]:
239        if isinstance(expression, str):
240            return exp.Literal.string(
241                # the time formats are quoted
242                format_time(expression[1:-1], cls.TIME_MAPPING, cls.TIME_TRIE)
243            )
244
245        if expression and expression.is_string:
246            return exp.Literal.string(format_time(expression.this, cls.TIME_MAPPING, cls.TIME_TRIE))
247
248        return expression
249
250    @classmethod
251    def normalize_identifier(cls, expression: E) -> E:
252        """
253        Normalizes an unquoted identifier to either lower or upper case, thus essentially
254        making it case-insensitive. If a dialect treats all identifiers as case-insensitive,
255        they will be normalized to lowercase regardless of being quoted or not.
256        """
257        if isinstance(expression, exp.Identifier) and (
258            not expression.quoted or cls.RESOLVES_IDENTIFIERS_AS_UPPERCASE is None
259        ):
260            expression.set(
261                "this",
262                expression.this.upper()
263                if cls.RESOLVES_IDENTIFIERS_AS_UPPERCASE
264                else expression.this.lower(),
265            )
266
267        return expression
268
269    @classmethod
270    def case_sensitive(cls, text: str) -> bool:
271        """Checks if text contains any case sensitive characters, based on the dialect's rules."""
272        if cls.RESOLVES_IDENTIFIERS_AS_UPPERCASE is None:
273            return False
274
275        unsafe = str.islower if cls.RESOLVES_IDENTIFIERS_AS_UPPERCASE else str.isupper
276        return any(unsafe(char) for char in text)
277
278    @classmethod
279    def can_identify(cls, text: str, identify: str | bool = "safe") -> bool:
280        """Checks if text can be identified given an identify option.
281
282        Args:
283            text: The text to check.
284            identify:
285                "always" or `True`: Always returns true.
286                "safe": True if the identifier is case-insensitive.
287
288        Returns:
289            Whether or not the given text can be identified.
290        """
291        if identify is True or identify == "always":
292            return True
293
294        if identify == "safe":
295            return not cls.case_sensitive(text)
296
297        return False
298
299    @classmethod
300    def quote_identifier(cls, expression: E, identify: bool = True) -> E:
301        if isinstance(expression, exp.Identifier):
302            name = expression.this
303            expression.set(
304                "quoted",
305                identify or cls.case_sensitive(name) or not exp.SAFE_IDENTIFIER_RE.match(name),
306            )
307
308        return expression
309
310    def parse(self, sql: str, **opts) -> t.List[t.Optional[exp.Expression]]:
311        return self.parser(**opts).parse(self.tokenize(sql), sql)
312
313    def parse_into(
314        self, expression_type: exp.IntoType, sql: str, **opts
315    ) -> t.List[t.Optional[exp.Expression]]:
316        return self.parser(**opts).parse_into(expression_type, self.tokenize(sql), sql)
317
318    def generate(self, expression: exp.Expression, copy: bool = True, **opts) -> str:
319        return self.generator(**opts).generate(expression, copy=copy)
320
321    def transpile(self, sql: str, **opts) -> t.List[str]:
322        return [
323            self.generate(expression, copy=False, **opts) if expression else ""
324            for expression in self.parse(sql)
325        ]
326
327    def tokenize(self, sql: str) -> t.List[Token]:
328        return self.tokenizer.tokenize(sql)
329
330    @property
331    def tokenizer(self) -> Tokenizer:
332        if not hasattr(self, "_tokenizer"):
333            self._tokenizer = self.tokenizer_class()
334        return self._tokenizer
335
336    def parser(self, **opts) -> Parser:
337        return self.parser_class(**opts)
338
339    def generator(self, **opts) -> Generator:
340        return self.generator_class(**opts)
341
342
343DialectType = t.Union[str, Dialect, t.Type[Dialect], None]
344
345
346def rename_func(name: str) -> t.Callable[[Generator, exp.Expression], str]:
347    return lambda self, expression: self.func(name, *flatten(expression.args.values()))
348
349
350def approx_count_distinct_sql(self: Generator, expression: exp.ApproxDistinct) -> str:
351    if expression.args.get("accuracy"):
352        self.unsupported("APPROX_COUNT_DISTINCT does not support accuracy")
353    return self.func("APPROX_COUNT_DISTINCT", expression.this)
354
355
356def if_sql(
357    name: str = "IF", false_value: t.Optional[exp.Expression | str] = None
358) -> t.Callable[[Generator, exp.If], str]:
359    def _if_sql(self: Generator, expression: exp.If) -> str:
360        return self.func(
361            name,
362            expression.this,
363            expression.args.get("true"),
364            expression.args.get("false") or false_value,
365        )
366
367    return _if_sql
368
369
370def arrow_json_extract_sql(self: Generator, expression: exp.JSONExtract | exp.JSONBExtract) -> str:
371    return self.binary(expression, "->")
372
373
374def arrow_json_extract_scalar_sql(
375    self: Generator, expression: exp.JSONExtractScalar | exp.JSONBExtractScalar
376) -> str:
377    return self.binary(expression, "->>")
378
379
380def inline_array_sql(self: Generator, expression: exp.Array) -> str:
381    return f"[{self.expressions(expression, flat=True)}]"
382
383
384def no_ilike_sql(self: Generator, expression: exp.ILike) -> str:
385    return self.like_sql(
386        exp.Like(this=exp.Lower(this=expression.this), expression=expression.expression)
387    )
388
389
390def no_paren_current_date_sql(self: Generator, expression: exp.CurrentDate) -> str:
391    zone = self.sql(expression, "this")
392    return f"CURRENT_DATE AT TIME ZONE {zone}" if zone else "CURRENT_DATE"
393
394
395def no_recursive_cte_sql(self: Generator, expression: exp.With) -> str:
396    if expression.args.get("recursive"):
397        self.unsupported("Recursive CTEs are unsupported")
398        expression.args["recursive"] = False
399    return self.with_sql(expression)
400
401
402def no_safe_divide_sql(self: Generator, expression: exp.SafeDivide) -> str:
403    n = self.sql(expression, "this")
404    d = self.sql(expression, "expression")
405    return f"IF({d} <> 0, {n} / {d}, NULL)"
406
407
408def no_tablesample_sql(self: Generator, expression: exp.TableSample) -> str:
409    self.unsupported("TABLESAMPLE unsupported")
410    return self.sql(expression.this)
411
412
413def no_pivot_sql(self: Generator, expression: exp.Pivot) -> str:
414    self.unsupported("PIVOT unsupported")
415    return ""
416
417
418def no_trycast_sql(self: Generator, expression: exp.TryCast) -> str:
419    return self.cast_sql(expression)
420
421
422def no_properties_sql(self: Generator, expression: exp.Properties) -> str:
423    self.unsupported("Properties unsupported")
424    return ""
425
426
427def no_comment_column_constraint_sql(
428    self: Generator, expression: exp.CommentColumnConstraint
429) -> str:
430    self.unsupported("CommentColumnConstraint unsupported")
431    return ""
432
433
434def no_map_from_entries_sql(self: Generator, expression: exp.MapFromEntries) -> str:
435    self.unsupported("MAP_FROM_ENTRIES unsupported")
436    return ""
437
438
439def str_position_sql(self: Generator, expression: exp.StrPosition) -> str:
440    this = self.sql(expression, "this")
441    substr = self.sql(expression, "substr")
442    position = self.sql(expression, "position")
443    if position:
444        return f"STRPOS(SUBSTR({this}, {position}), {substr}) + {position} - 1"
445    return f"STRPOS({this}, {substr})"
446
447
448def struct_extract_sql(self: Generator, expression: exp.StructExtract) -> str:
449    return (
450        f"{self.sql(expression, 'this')}.{self.sql(exp.to_identifier(expression.expression.name))}"
451    )
452
453
454def var_map_sql(
455    self: Generator, expression: exp.Map | exp.VarMap, map_func_name: str = "MAP"
456) -> str:
457    keys = expression.args["keys"]
458    values = expression.args["values"]
459
460    if not isinstance(keys, exp.Array) or not isinstance(values, exp.Array):
461        self.unsupported("Cannot convert array columns into map.")
462        return self.func(map_func_name, keys, values)
463
464    args = []
465    for key, value in zip(keys.expressions, values.expressions):
466        args.append(self.sql(key))
467        args.append(self.sql(value))
468
469    return self.func(map_func_name, *args)
470
471
472def format_time_lambda(
473    exp_class: t.Type[E], dialect: str, default: t.Optional[bool | str] = None
474) -> t.Callable[[t.List], E]:
475    """Helper used for time expressions.
476
477    Args:
478        exp_class: the expression class to instantiate.
479        dialect: target sql dialect.
480        default: the default format, True being time.
481
482    Returns:
483        A callable that can be used to return the appropriately formatted time expression.
484    """
485
486    def _format_time(args: t.List):
487        return exp_class(
488            this=seq_get(args, 0),
489            format=Dialect[dialect].format_time(
490                seq_get(args, 1)
491                or (Dialect[dialect].TIME_FORMAT if default is True else default or None)
492            ),
493        )
494
495    return _format_time
496
497
498def time_format(
499    dialect: DialectType = None,
500) -> t.Callable[[Generator, exp.UnixToStr | exp.StrToUnix], t.Optional[str]]:
501    def _time_format(self: Generator, expression: exp.UnixToStr | exp.StrToUnix) -> t.Optional[str]:
502        """
503        Returns the time format for a given expression, unless it's equivalent
504        to the default time format of the dialect of interest.
505        """
506        time_format = self.format_time(expression)
507        return time_format if time_format != Dialect.get_or_raise(dialect).TIME_FORMAT else None
508
509    return _time_format
510
511
512def create_with_partitions_sql(self: Generator, expression: exp.Create) -> str:
513    """
514    In Hive and Spark, the PARTITIONED BY property acts as an extension of a table's schema. When the
515    PARTITIONED BY value is an array of column names, they are transformed into a schema. The corresponding
516    columns are removed from the create statement.
517    """
518    has_schema = isinstance(expression.this, exp.Schema)
519    is_partitionable = expression.args.get("kind") in ("TABLE", "VIEW")
520
521    if has_schema and is_partitionable:
522        prop = expression.find(exp.PartitionedByProperty)
523        if prop and prop.this and not isinstance(prop.this, exp.Schema):
524            schema = expression.this
525            columns = {v.name.upper() for v in prop.this.expressions}
526            partitions = [col for col in schema.expressions if col.name.upper() in columns]
527            schema.set("expressions", [e for e in schema.expressions if e not in partitions])
528            prop.replace(exp.PartitionedByProperty(this=exp.Schema(expressions=partitions)))
529            expression.set("this", schema)
530
531    return self.create_sql(expression)
532
533
534def parse_date_delta(
535    exp_class: t.Type[E], unit_mapping: t.Optional[t.Dict[str, str]] = None
536) -> t.Callable[[t.List], E]:
537    def inner_func(args: t.List) -> E:
538        unit_based = len(args) == 3
539        this = args[2] if unit_based else seq_get(args, 0)
540        unit = args[0] if unit_based else exp.Literal.string("DAY")
541        unit = exp.var(unit_mapping.get(unit.name.lower(), unit.name)) if unit_mapping else unit
542        return exp_class(this=this, expression=seq_get(args, 1), unit=unit)
543
544    return inner_func
545
546
547def parse_date_delta_with_interval(
548    expression_class: t.Type[E],
549) -> t.Callable[[t.List], t.Optional[E]]:
550    def func(args: t.List) -> t.Optional[E]:
551        if len(args) < 2:
552            return None
553
554        interval = args[1]
555
556        if not isinstance(interval, exp.Interval):
557            raise ParseError(f"INTERVAL expression expected but got '{interval}'")
558
559        expression = interval.this
560        if expression and expression.is_string:
561            expression = exp.Literal.number(expression.this)
562
563        return expression_class(
564            this=args[0], expression=expression, unit=exp.Literal.string(interval.text("unit"))
565        )
566
567    return func
568
569
570def date_trunc_to_time(args: t.List) -> exp.DateTrunc | exp.TimestampTrunc:
571    unit = seq_get(args, 0)
572    this = seq_get(args, 1)
573
574    if isinstance(this, exp.Cast) and this.is_type("date"):
575        return exp.DateTrunc(unit=unit, this=this)
576    return exp.TimestampTrunc(this=this, unit=unit)
577
578
579def date_add_interval_sql(
580    data_type: str, kind: str
581) -> t.Callable[[Generator, exp.Expression], str]:
582    def func(self: Generator, expression: exp.Expression) -> str:
583        this = self.sql(expression, "this")
584        unit = expression.args.get("unit")
585        unit = exp.var(unit.name.upper() if unit else "DAY")
586        interval = exp.Interval(this=expression.expression, unit=unit)
587        return f"{data_type}_{kind}({this}, {self.sql(interval)})"
588
589    return func
590
591
592def timestamptrunc_sql(self: Generator, expression: exp.TimestampTrunc) -> str:
593    return self.func(
594        "DATE_TRUNC", exp.Literal.string(expression.text("unit") or "day"), expression.this
595    )
596
597
598def no_timestamp_sql(self: Generator, expression: exp.Timestamp) -> str:
599    if not expression.expression:
600        return self.sql(exp.cast(expression.this, to=exp.DataType.Type.TIMESTAMP))
601    if expression.text("expression").lower() in TIMEZONES:
602        return self.sql(
603            exp.AtTimeZone(
604                this=exp.cast(expression.this, to=exp.DataType.Type.TIMESTAMP),
605                zone=expression.expression,
606            )
607        )
608    return self.function_fallback_sql(expression)
609
610
611def locate_to_strposition(args: t.List) -> exp.Expression:
612    return exp.StrPosition(
613        this=seq_get(args, 1), substr=seq_get(args, 0), position=seq_get(args, 2)
614    )
615
616
617def strposition_to_locate_sql(self: Generator, expression: exp.StrPosition) -> str:
618    return self.func(
619        "LOCATE", expression.args.get("substr"), expression.this, expression.args.get("position")
620    )
621
622
623def left_to_substring_sql(self: Generator, expression: exp.Left) -> str:
624    return self.sql(
625        exp.Substring(
626            this=expression.this, start=exp.Literal.number(1), length=expression.expression
627        )
628    )
629
630
631def right_to_substring_sql(self: Generator, expression: exp.Left) -> str:
632    return self.sql(
633        exp.Substring(
634            this=expression.this,
635            start=exp.Length(this=expression.this) - exp.paren(expression.expression - 1),
636        )
637    )
638
639
640def timestrtotime_sql(self: Generator, expression: exp.TimeStrToTime) -> str:
641    return self.sql(exp.cast(expression.this, "timestamp"))
642
643
644def datestrtodate_sql(self: Generator, expression: exp.DateStrToDate) -> str:
645    return self.sql(exp.cast(expression.this, "date"))
646
647
648# Used for Presto and Duckdb which use functions that don't support charset, and assume utf-8
649def encode_decode_sql(
650    self: Generator, expression: exp.Expression, name: str, replace: bool = True
651) -> str:
652    charset = expression.args.get("charset")
653    if charset and charset.name.lower() != "utf-8":
654        self.unsupported(f"Expected utf-8 character set, got {charset}.")
655
656    return self.func(name, expression.this, expression.args.get("replace") if replace else None)
657
658
659def min_or_least(self: Generator, expression: exp.Min) -> str:
660    name = "LEAST" if expression.expressions else "MIN"
661    return rename_func(name)(self, expression)
662
663
664def max_or_greatest(self: Generator, expression: exp.Max) -> str:
665    name = "GREATEST" if expression.expressions else "MAX"
666    return rename_func(name)(self, expression)
667
668
669def count_if_to_sum(self: Generator, expression: exp.CountIf) -> str:
670    cond = expression.this
671
672    if isinstance(expression.this, exp.Distinct):
673        cond = expression.this.expressions[0]
674        self.unsupported("DISTINCT is not supported when converting COUNT_IF to SUM")
675
676    return self.func("sum", exp.func("if", cond, 1, 0))
677
678
679def trim_sql(self: Generator, expression: exp.Trim) -> str:
680    target = self.sql(expression, "this")
681    trim_type = self.sql(expression, "position")
682    remove_chars = self.sql(expression, "expression")
683    collation = self.sql(expression, "collation")
684
685    # Use TRIM/LTRIM/RTRIM syntax if the expression isn't database-specific
686    if not remove_chars and not collation:
687        return self.trim_sql(expression)
688
689    trim_type = f"{trim_type} " if trim_type else ""
690    remove_chars = f"{remove_chars} " if remove_chars else ""
691    from_part = "FROM " if trim_type or remove_chars else ""
692    collation = f" COLLATE {collation}" if collation else ""
693    return f"TRIM({trim_type}{remove_chars}{from_part}{target}{collation})"
694
695
696def str_to_time_sql(self: Generator, expression: exp.Expression) -> str:
697    return self.func("STRPTIME", expression.this, self.format_time(expression))
698
699
700def ts_or_ds_to_date_sql(dialect: str) -> t.Callable:
701    def _ts_or_ds_to_date_sql(self: Generator, expression: exp.TsOrDsToDate) -> str:
702        _dialect = Dialect.get_or_raise(dialect)
703        time_format = self.format_time(expression)
704        if time_format and time_format not in (_dialect.TIME_FORMAT, _dialect.DATE_FORMAT):
705            return self.sql(
706                exp.cast(
707                    exp.StrToTime(this=expression.this, format=expression.args["format"]),
708                    "date",
709                )
710            )
711        return self.sql(exp.cast(expression.this, "date"))
712
713    return _ts_or_ds_to_date_sql
714
715
716def concat_to_dpipe_sql(self: Generator, expression: exp.Concat | exp.SafeConcat) -> str:
717    return self.sql(reduce(lambda x, y: exp.DPipe(this=x, expression=y), expression.expressions))
718
719
720def concat_ws_to_dpipe_sql(self: Generator, expression: exp.ConcatWs) -> str:
721    delim, *rest_args = expression.expressions
722    return self.sql(
723        reduce(
724            lambda x, y: exp.DPipe(this=x, expression=exp.DPipe(this=delim, expression=y)),
725            rest_args,
726        )
727    )
728
729
730def regexp_extract_sql(self: Generator, expression: exp.RegexpExtract) -> str:
731    bad_args = list(filter(expression.args.get, ("position", "occurrence", "parameters")))
732    if bad_args:
733        self.unsupported(f"REGEXP_EXTRACT does not support the following arg(s): {bad_args}")
734
735    return self.func(
736        "REGEXP_EXTRACT", expression.this, expression.expression, expression.args.get("group")
737    )
738
739
740def regexp_replace_sql(self: Generator, expression: exp.RegexpReplace) -> str:
741    bad_args = list(
742        filter(expression.args.get, ("position", "occurrence", "parameters", "modifiers"))
743    )
744    if bad_args:
745        self.unsupported(f"REGEXP_REPLACE does not support the following arg(s): {bad_args}")
746
747    return self.func(
748        "REGEXP_REPLACE", expression.this, expression.expression, expression.args["replacement"]
749    )
750
751
752def pivot_column_names(aggregations: t.List[exp.Expression], dialect: DialectType) -> t.List[str]:
753    names = []
754    for agg in aggregations:
755        if isinstance(agg, exp.Alias):
756            names.append(agg.alias)
757        else:
758            """
759            This case corresponds to aggregations without aliases being used as suffixes
760            (e.g. col_avg(foo)). We need to unquote identifiers because they're going to
761            be quoted in the base parser's `_parse_pivot` method, due to `to_identifier`.
762            Otherwise, we'd end up with `col_avg(`foo`)` (notice the double quotes).
763            """
764            agg_all_unquoted = agg.transform(
765                lambda node: exp.Identifier(this=node.name, quoted=False)
766                if isinstance(node, exp.Identifier)
767                else node
768            )
769            names.append(agg_all_unquoted.sql(dialect=dialect, normalize_functions="lower"))
770
771    return names
772
773
774def binary_from_function(expr_type: t.Type[B]) -> t.Callable[[t.List], B]:
775    return lambda args: expr_type(this=seq_get(args, 0), expression=seq_get(args, 1))
776
777
778# Used to represent DATE_TRUNC in Doris, Postgres and Starrocks dialects
779def parse_timestamp_trunc(args: t.List) -> exp.TimestampTrunc:
780    return exp.TimestampTrunc(this=seq_get(args, 1), unit=seq_get(args, 0))
781
782
783def any_value_to_max_sql(self: Generator, expression: exp.AnyValue) -> str:
784    return self.func("MAX", expression.this)
785
786
787def bool_xor_sql(self: Generator, expression: exp.Xor) -> str:
788    a = self.sql(expression.left)
789    b = self.sql(expression.right)
790    return f"({a} AND (NOT {b})) OR ((NOT {a}) AND {b})"
791
792
793# Used to generate JSON_OBJECT with a comma in BigQuery and MySQL instead of colon
794def json_keyvalue_comma_sql(self: Generator, expression: exp.JSONKeyValue) -> str:
795    return f"{self.sql(expression, 'this')}, {self.sql(expression, 'expression')}"
796
797
798def is_parse_json(expression: exp.Expression) -> bool:
799    return isinstance(expression, exp.ParseJSON) or (
800        isinstance(expression, exp.Cast) and expression.is_type("json")
801    )
802
803
804def isnull_to_is_null(args: t.List) -> exp.Expression:
805    return exp.Paren(this=exp.Is(this=seq_get(args, 0), expression=exp.null()))
806
807
808def generatedasidentitycolumnconstraint_sql(
809    self: Generator, expression: exp.GeneratedAsIdentityColumnConstraint
810) -> str:
811    start = self.sql(expression, "start") or "1"
812    increment = self.sql(expression, "increment") or "1"
813    return f"IDENTITY({start}, {increment})"
814
815
816def arg_max_or_min_no_count(name: str) -> t.Callable[[Generator, exp.ArgMax | exp.ArgMin], str]:
817    def _arg_max_or_min_sql(self: Generator, expression: exp.ArgMax | exp.ArgMin) -> str:
818        if expression.args.get("count"):
819            self.unsupported(f"Only two arguments are supported in function {name}.")
820
821        return self.func(name, expression.this, expression.expression)
822
823    return _arg_max_or_min_sql