Merging upstream version 18.2.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

sqlglot/parser.py

@@ -136,6 +136,7 @@ class Parser(metaclass=_Parser):
         TokenType.UINT128,
         TokenType.INT256,
         TokenType.UINT256,
+        TokenType.MEDIUMINT,
         TokenType.FIXEDSTRING,
         TokenType.FLOAT,
         TokenType.DOUBLE,
@@ -186,6 +187,7 @@ class Parser(metaclass=_Parser):
         TokenType.SMALLSERIAL,
         TokenType.BIGSERIAL,
         TokenType.XML,
+        TokenType.YEAR,
         TokenType.UNIQUEIDENTIFIER,
         TokenType.USERDEFINED,
         TokenType.MONEY,
@@ -194,9 +196,12 @@ class Parser(metaclass=_Parser):
         TokenType.IMAGE,
         TokenType.VARIANT,
         TokenType.OBJECT,
+        TokenType.OBJECT_IDENTIFIER,
         TokenType.INET,
         TokenType.IPADDRESS,
         TokenType.IPPREFIX,
+        TokenType.UNKNOWN,
+        TokenType.NULL,
         *ENUM_TYPE_TOKENS,
         *NESTED_TYPE_TOKENS,
     }
@@ -332,6 +337,7 @@ class Parser(metaclass=_Parser):
         TokenType.INDEX,
         TokenType.ISNULL,
         TokenType.ILIKE,
+        TokenType.INSERT,
         TokenType.LIKE,
         TokenType.MERGE,
         TokenType.OFFSET,
@@ -487,7 +493,7 @@ class Parser(metaclass=_Parser):
         exp.Cluster: lambda self: self._parse_sort(exp.Cluster, TokenType.CLUSTER_BY),
         exp.Column: lambda self: self._parse_column(),
         exp.Condition: lambda self: self._parse_conjunction(),
-        exp.DataType: lambda self: self._parse_types(),
+        exp.DataType: lambda self: self._parse_types(allow_identifiers=False),
         exp.Expression: lambda self: self._parse_statement(),
         exp.From: lambda self: self._parse_from(),
         exp.Group: lambda self: self._parse_group(),
@@ -523,9 +529,6 @@ class Parser(metaclass=_Parser):
         TokenType.DESC: lambda self: self._parse_describe(),
         TokenType.DESCRIBE: lambda self: self._parse_describe(),
         TokenType.DROP: lambda self: self._parse_drop(),
-        TokenType.FROM: lambda self: exp.select("*").from_(
-            t.cast(exp.From, self._parse_from(skip_from_token=True))
-        ),
         TokenType.INSERT: lambda self: self._parse_insert(),
         TokenType.LOAD: lambda self: self._parse_load(),
         TokenType.MERGE: lambda self: self._parse_merge(),
@@ -578,7 +581,7 @@ class Parser(metaclass=_Parser):
         TokenType.PLACEHOLDER: lambda self: self.expression(exp.Placeholder),
         TokenType.PARAMETER: lambda self: self._parse_parameter(),
         TokenType.COLON: lambda self: self.expression(exp.Placeholder, this=self._prev.text)
-        if self._match_set((TokenType.NUMBER, TokenType.VAR))
+        if self._match(TokenType.NUMBER) or self._match_set(self.ID_VAR_TOKENS)
         else None,
     }
 
@@ -593,6 +596,7 @@ class Parser(metaclass=_Parser):
         TokenType.OVERLAPS: binary_range_parser(exp.Overlaps),
         TokenType.RLIKE: binary_range_parser(exp.RegexpLike),
         TokenType.SIMILAR_TO: binary_range_parser(exp.SimilarTo),
+        TokenType.FOR: lambda self, this: self._parse_comprehension(this),
     }
 
     PROPERTY_PARSERS: t.Dict[str, t.Callable] = {
@@ -684,6 +688,12 @@ class Parser(metaclass=_Parser):
             exp.CommentColumnConstraint, this=self._parse_string()
         ),
         "COMPRESS": lambda self: self._parse_compress(),
+        "CLUSTERED": lambda self: self.expression(
+            exp.ClusteredColumnConstraint, this=self._parse_wrapped_csv(self._parse_ordered)
+        ),
+        "NONCLUSTERED": lambda self: self.expression(
+            exp.NonClusteredColumnConstraint, this=self._parse_wrapped_csv(self._parse_ordered)
+        ),
         "DEFAULT": lambda self: self.expression(
             exp.DefaultColumnConstraint, this=self._parse_bitwise()
         ),
@@ -698,8 +708,11 @@ class Parser(metaclass=_Parser):
         "LIKE": lambda self: self._parse_create_like(),
         "NOT": lambda self: self._parse_not_constraint(),
         "NULL": lambda self: self.expression(exp.NotNullColumnConstraint, allow_null=True),
-        "ON": lambda self: self._match(TokenType.UPDATE)
-        and self.expression(exp.OnUpdateColumnConstraint, this=self._parse_function()),
+        "ON": lambda self: (
+            self._match(TokenType.UPDATE)
+            and self.expression(exp.OnUpdateColumnConstraint, this=self._parse_function())
+        )
+        or self.expression(exp.OnProperty, this=self._parse_id_var()),
         "PATH": lambda self: self.expression(exp.PathColumnConstraint, this=self._parse_string()),
         "PRIMARY KEY": lambda self: self._parse_primary_key(),
         "REFERENCES": lambda self: self._parse_references(match=False),
@@ -709,6 +722,9 @@ class Parser(metaclass=_Parser):
         "TTL": lambda self: self.expression(exp.MergeTreeTTL, expressions=[self._parse_bitwise()]),
         "UNIQUE": lambda self: self._parse_unique(),
         "UPPERCASE": lambda self: self.expression(exp.UppercaseColumnConstraint),
+        "WITH": lambda self: self.expression(
+            exp.Properties, expressions=self._parse_wrapped_csv(self._parse_property)
+        ),
     }
 
     ALTER_PARSERS = {
@@ -728,6 +744,11 @@ class Parser(metaclass=_Parser):
         "NEXT": lambda self: self._parse_next_value_for(),
     }
 
+    INVALID_FUNC_NAME_TOKENS = {
+        TokenType.IDENTIFIER,
+        TokenType.STRING,
+    }
+
     FUNCTIONS_WITH_ALIASED_ARGS = {"STRUCT"}
 
     FUNCTION_PARSERS = {
@@ -774,6 +795,8 @@ class Parser(metaclass=_Parser):
             self._parse_sort(exp.Distribute, TokenType.DISTRIBUTE_BY),
         ),
         TokenType.SORT_BY: lambda self: ("sort", self._parse_sort(exp.Sort, TokenType.SORT_BY)),
+        TokenType.CONNECT_BY: lambda self: ("connect", self._parse_connect(skip_start_token=True)),
+        TokenType.START_WITH: lambda self: ("connect", self._parse_connect()),
     }
 
     SET_PARSERS = {
@@ -815,6 +838,8 @@ class Parser(metaclass=_Parser):
 
     ADD_CONSTRAINT_TOKENS = {TokenType.CONSTRAINT, TokenType.PRIMARY_KEY, TokenType.FOREIGN_KEY}
 
+    DISTINCT_TOKENS = {TokenType.DISTINCT}
+
     STRICT_CAST = True
 
     # A NULL arg in CONCAT yields NULL by default
@@ -826,6 +851,11 @@ class Parser(metaclass=_Parser):
     LOG_BASE_FIRST = True
     LOG_DEFAULTS_TO_LN = False
 
+    SUPPORTS_USER_DEFINED_TYPES = True
+
+    # Whether or not ADD is present for each column added by ALTER TABLE
+    ALTER_TABLE_ADD_COLUMN_KEYWORD = True
+
     __slots__ = (
         "error_level",
         "error_message_context",
@@ -838,9 +868,11 @@ class Parser(metaclass=_Parser):
         "_next",
         "_prev",
         "_prev_comments",
+        "_tokenizer",
     )
 
     # Autofilled
+    TOKENIZER_CLASS: t.Type[Tokenizer] = Tokenizer
     INDEX_OFFSET: int = 0
     UNNEST_COLUMN_ONLY: bool = False
     ALIAS_POST_TABLESAMPLE: bool = False
@@ -863,6 +895,7 @@ class Parser(metaclass=_Parser):
         self.error_level = error_level or ErrorLevel.IMMEDIATE
         self.error_message_context = error_message_context
         self.max_errors = max_errors
+        self._tokenizer = self.TOKENIZER_CLASS()
         self.reset()
 
     def reset(self):
@@ -1148,7 +1181,7 @@ class Parser(metaclass=_Parser):
         expression = self._parse_set_operations(expression) if expression else self._parse_select()
         return self._parse_query_modifiers(expression)
 
-    def _parse_drop(self) -> exp.Drop | exp.Command:
+    def _parse_drop(self, exists: bool = False) -> exp.Drop | exp.Command:
         start = self._prev
         temporary = self._match(TokenType.TEMPORARY)
         materialized = self._match_text_seq("MATERIALIZED")
@@ -1160,7 +1193,7 @@ class Parser(metaclass=_Parser):
         return self.expression(
             exp.Drop,
             comments=start.comments,
-            exists=self._parse_exists(),
+            exists=exists or self._parse_exists(),
             this=self._parse_table(schema=True),
             kind=kind,
             temporary=temporary,
@@ -1274,6 +1307,8 @@ class Parser(metaclass=_Parser):
                 if self._match_text_seq("WITH", "NO", "SCHEMA", "BINDING"):
                     no_schema_binding = True
 
+            shallow = self._match_text_seq("SHALLOW")
+
             if self._match_text_seq("CLONE"):
                 clone = self._parse_table(schema=True)
                 when = self._match_texts({"AT", "BEFORE"}) and self._prev.text.upper()
@@ -1285,7 +1320,12 @@ class Parser(metaclass=_Parser):
                 clone_expression = self._match(TokenType.FARROW) and self._parse_bitwise()
                 self._match(TokenType.R_PAREN)
                 clone = self.expression(
-                    exp.Clone, this=clone, when=when, kind=clone_kind, expression=clone_expression
+                    exp.Clone,
+                    this=clone,
+                    when=when,
+                    kind=clone_kind,
+                    shallow=shallow,
+                    expression=clone_expression,
                 )
 
         return self.expression(
@@ -1349,7 +1389,11 @@ class Parser(metaclass=_Parser):
         if assignment:
             key = self._parse_var_or_string()
             self._match(TokenType.EQ)
-            return self.expression(exp.Property, this=key, value=self._parse_column())
+            return self.expression(
+                exp.Property,
+                this=key,
+                value=self._parse_column() or self._parse_var(any_token=True),
+            )
 
         return None
 
@@ -1409,7 +1453,7 @@ class Parser(metaclass=_Parser):
 
     def _parse_with_property(
         self,
-    ) -> t.Optional[exp.Expression] | t.List[t.Optional[exp.Expression]]:
+    ) -> t.Optional[exp.Expression] | t.List[exp.Expression]:
         if self._match(TokenType.L_PAREN, advance=False):
             return self._parse_wrapped_csv(self._parse_property)
 
@@ -1622,7 +1666,7 @@ class Parser(metaclass=_Parser):
             override=override,
         )
 
-    def _parse_partition_by(self) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_partition_by(self) -> t.List[exp.Expression]:
         if self._match(TokenType.PARTITION_BY):
             return self._parse_csv(self._parse_conjunction)
         return []
@@ -1652,9 +1696,9 @@ class Parser(metaclass=_Parser):
     def _parse_on_property(self) -> t.Optional[exp.Expression]:
         if self._match_text_seq("COMMIT", "PRESERVE", "ROWS"):
             return exp.OnCommitProperty()
-        elif self._match_text_seq("COMMIT", "DELETE", "ROWS"):
+        if self._match_text_seq("COMMIT", "DELETE", "ROWS"):
             return exp.OnCommitProperty(delete=True)
-        return None
+        return self.expression(exp.OnProperty, this=self._parse_schema(self._parse_id_var()))
 
     def _parse_distkey(self) -> exp.DistKeyProperty:
         return self.expression(exp.DistKeyProperty, this=self._parse_wrapped(self._parse_id_var))
@@ -1709,8 +1753,10 @@ class Parser(metaclass=_Parser):
 
     def _parse_describe(self) -> exp.Describe:
         kind = self._match_set(self.CREATABLES) and self._prev.text
-        this = self._parse_table()
-        return self.expression(exp.Describe, this=this, kind=kind)
+        this = self._parse_table(schema=True)
+        properties = self._parse_properties()
+        expressions = properties.expressions if properties else None
+        return self.expression(exp.Describe, this=this, kind=kind, expressions=expressions)
 
     def _parse_insert(self) -> exp.Insert:
         comments = ensure_list(self._prev_comments)
@@ -1741,6 +1787,7 @@ class Parser(metaclass=_Parser):
             exp.Insert,
             comments=comments,
             this=this,
+            by_name=self._match_text_seq("BY", "NAME"),
             exists=self._parse_exists(),
             partition=self._parse_partition(),
             where=self._match_pair(TokenType.REPLACE, TokenType.WHERE)
@@ -1895,6 +1942,7 @@ class Parser(metaclass=_Parser):
                 "from": self._parse_from(joins=True),
                 "where": self._parse_where(),
                 "returning": returning or self._parse_returning(),
+                "order": self._parse_order(),
                 "limit": self._parse_limit(),
             },
         )
@@ -1948,13 +1996,14 @@ class Parser(metaclass=_Parser):
         # https://prestodb.io/docs/current/sql/values.html
         return self.expression(exp.Tuple, expressions=[self._parse_conjunction()])
 
-    def _parse_projections(self) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_projections(self) -> t.List[exp.Expression]:
         return self._parse_expressions()
 
     def _parse_select(
         self, nested: bool = False, table: bool = False, parse_subquery_alias: bool = True
     ) -> t.Optional[exp.Expression]:
         cte = self._parse_with()
+
         if cte:
             this = self._parse_statement()
 
@@ -1967,12 +2016,18 @@ class Parser(metaclass=_Parser):
             else:
                 self.raise_error(f"{this.key} does not support CTE")
                 this = cte
-        elif self._match(TokenType.SELECT):
+
+            return this
+
+        # duckdb supports leading with FROM x
+        from_ = self._parse_from() if self._match(TokenType.FROM, advance=False) else None
+
+        if self._match(TokenType.SELECT):
             comments = self._prev_comments
 
             hint = self._parse_hint()
             all_ = self._match(TokenType.ALL)
-            distinct = self._match(TokenType.DISTINCT)
+            distinct = self._match_set(self.DISTINCT_TOKENS)
 
             kind = (
                 self._match(TokenType.ALIAS)
@@ -2006,7 +2061,9 @@ class Parser(metaclass=_Parser):
             if into:
                 this.set("into", into)
 
-            from_ = self._parse_from()
+            if not from_:
+                from_ = self._parse_from()
+
             if from_:
                 this.set("from", from_)
 
@@ -2033,6 +2090,8 @@ class Parser(metaclass=_Parser):
                 expressions=self._parse_csv(self._parse_value),
                 alias=self._parse_table_alias(),
             )
+        elif from_:
+            this = exp.select("*").from_(from_.this, copy=False)
         else:
             this = None
 
@@ -2491,6 +2550,11 @@ class Parser(metaclass=_Parser):
         if schema:
             return self._parse_schema(this=this)
 
+        version = self._parse_version()
+
+        if version:
+            this.set("version", version)
+
         if self.ALIAS_POST_TABLESAMPLE:
             table_sample = self._parse_table_sample()
 
@@ -2498,11 +2562,11 @@ class Parser(metaclass=_Parser):
         if alias:
             this.set("alias", alias)
 
+        this.set("hints", self._parse_table_hints())
+
         if not this.args.get("pivots"):
             this.set("pivots", self._parse_pivots())
 
-        this.set("hints", self._parse_table_hints())
-
         if not self.ALIAS_POST_TABLESAMPLE:
             table_sample = self._parse_table_sample()
 
@@ -2516,6 +2580,37 @@ class Parser(metaclass=_Parser):
 
         return this
 
+    def _parse_version(self) -> t.Optional[exp.Version]:
+        if self._match(TokenType.TIMESTAMP_SNAPSHOT):
+            this = "TIMESTAMP"
+        elif self._match(TokenType.VERSION_SNAPSHOT):
+            this = "VERSION"
+        else:
+            return None
+
+        if self._match_set((TokenType.FROM, TokenType.BETWEEN)):
+            kind = self._prev.text.upper()
+            start = self._parse_bitwise()
+            self._match_texts(("TO", "AND"))
+            end = self._parse_bitwise()
+            expression: t.Optional[exp.Expression] = self.expression(
+                exp.Tuple, expressions=[start, end]
+            )
+        elif self._match_text_seq("CONTAINED", "IN"):
+            kind = "CONTAINED IN"
+            expression = self.expression(
+                exp.Tuple, expressions=self._parse_wrapped_csv(self._parse_bitwise)
+            )
+        elif self._match(TokenType.ALL):
+            kind = "ALL"
+            expression = None
+        else:
+            self._match_text_seq("AS", "OF")
+            kind = "AS OF"
+            expression = self._parse_type()
+
+        return self.expression(exp.Version, this=this, expression=expression, kind=kind)
+
     def _parse_unnest(self, with_alias: bool = True) -> t.Optional[exp.Unnest]:
         if not self._match(TokenType.UNNEST):
             return None
@@ -2760,7 +2855,7 @@ class Parser(metaclass=_Parser):
 
         return self.expression(exp.Group, **elements)  # type: ignore
 
-    def _parse_grouping_sets(self) -> t.Optional[t.List[t.Optional[exp.Expression]]]:
+    def _parse_grouping_sets(self) -> t.Optional[t.List[exp.Expression]]:
         if not self._match(TokenType.GROUPING_SETS):
             return None
 
@@ -2784,6 +2879,22 @@ class Parser(metaclass=_Parser):
             return None
         return self.expression(exp.Qualify, this=self._parse_conjunction())
 
+    def _parse_connect(self, skip_start_token: bool = False) -> t.Optional[exp.Connect]:
+        if skip_start_token:
+            start = None
+        elif self._match(TokenType.START_WITH):
+            start = self._parse_conjunction()
+        else:
+            return None
+
+        self._match(TokenType.CONNECT_BY)
+        self.NO_PAREN_FUNCTION_PARSERS["PRIOR"] = lambda self: self.expression(
+            exp.Prior, this=self._parse_bitwise()
+        )
+        connect = self._parse_conjunction()
+        self.NO_PAREN_FUNCTION_PARSERS.pop("PRIOR")
+        return self.expression(exp.Connect, start=start, connect=connect)
+
     def _parse_order(
         self, this: t.Optional[exp.Expression] = None, skip_order_token: bool = False
     ) -> t.Optional[exp.Expression]:
@@ -2929,6 +3040,7 @@ class Parser(metaclass=_Parser):
             expression,
             this=this,
             distinct=self._match(TokenType.DISTINCT) or not self._match(TokenType.ALL),
+            by_name=self._match_text_seq("BY", "NAME"),
             expression=self._parse_set_operations(self._parse_select(nested=True)),
         )
 
@@ -3017,6 +3129,8 @@ class Parser(metaclass=_Parser):
         return self.expression(exp.Escape, this=this, expression=self._parse_string())
 
     def _parse_interval(self) -> t.Optional[exp.Interval]:
+        index = self._index
+
         if not self._match(TokenType.INTERVAL):
             return None
 
@@ -3025,7 +3139,11 @@ class Parser(metaclass=_Parser):
         else:
             this = self._parse_term()
 
-        unit = self._parse_function() or self._parse_var()
+        if not this:
+            self._retreat(index)
+            return None
+
+        unit = self._parse_function() or self._parse_var(any_token=True)
 
         # Most dialects support, e.g., the form INTERVAL '5' day, thus we try to parse
         # each INTERVAL expression into this canonical form so it's easy to transpile
@@ -3036,12 +3154,12 @@ class Parser(metaclass=_Parser):
 
             if len(parts) == 2:
                 if unit:
-                    # this is not actually a unit, it's something else
+                    # This is not actually a unit, it's something else (e.g. a "window side")
                     unit = None
                     self._retreat(self._index - 1)
-                else:
-                    this = exp.Literal.string(parts[0])
-                    unit = self.expression(exp.Var, this=parts[1])
+
+                this = exp.Literal.string(parts[0])
+                unit = self.expression(exp.Var, this=parts[1])
 
         return self.expression(exp.Interval, this=this, unit=unit)
 
@@ -3087,7 +3205,7 @@ class Parser(metaclass=_Parser):
             return interval
 
         index = self._index
-        data_type = self._parse_types(check_func=True)
+        data_type = self._parse_types(check_func=True, allow_identifiers=False)
         this = self._parse_column()
 
         if data_type:
@@ -3103,30 +3221,50 @@ class Parser(metaclass=_Parser):
 
         return this
 
-    def _parse_type_size(self) -> t.Optional[exp.DataTypeSize]:
+    def _parse_type_size(self) -> t.Optional[exp.DataTypeParam]:
         this = self._parse_type()
         if not this:
             return None
 
         return self.expression(
-            exp.DataTypeSize, this=this, expression=self._parse_var(any_token=True)
+            exp.DataTypeParam, this=this, expression=self._parse_var(any_token=True)
         )
 
     def _parse_types(
-        self, check_func: bool = False, schema: bool = False
+        self, check_func: bool = False, schema: bool = False, allow_identifiers: bool = True
     ) -> t.Optional[exp.Expression]:
         index = self._index
 
         prefix = self._match_text_seq("SYSUDTLIB", ".")
 
         if not self._match_set(self.TYPE_TOKENS):
-            return None
+            identifier = allow_identifiers and self._parse_id_var(
+                any_token=False, tokens=(TokenType.VAR,)
+            )
+
+            if identifier:
+                tokens = self._tokenizer.tokenize(identifier.name)
+
+                if len(tokens) != 1:
+                    self.raise_error("Unexpected identifier", self._prev)
+
+                if tokens[0].token_type in self.TYPE_TOKENS:
+                    self._prev = tokens[0]
+                elif self.SUPPORTS_USER_DEFINED_TYPES:
+                    return identifier
+                else:
+                    return None
+            else:
+                return None
 
         type_token = self._prev.token_type
 
         if type_token == TokenType.PSEUDO_TYPE:
             return self.expression(exp.PseudoType, this=self._prev.text)
 
+        if type_token == TokenType.OBJECT_IDENTIFIER:
+            return self.expression(exp.ObjectIdentifier, this=self._prev.text)
+
         nested = type_token in self.NESTED_TYPE_TOKENS
         is_struct = type_token in self.STRUCT_TYPE_TOKENS
         expressions = None
@@ -3137,7 +3275,9 @@ class Parser(metaclass=_Parser):
                 expressions = self._parse_csv(self._parse_struct_types)
             elif nested:
                 expressions = self._parse_csv(
-                    lambda: self._parse_types(check_func=check_func, schema=schema)
+                    lambda: self._parse_types(
+                        check_func=check_func, schema=schema, allow_identifiers=allow_identifiers
+                    )
                 )
             elif type_token in self.ENUM_TYPE_TOKENS:
                 expressions = self._parse_csv(self._parse_equality)
@@ -3151,14 +3291,16 @@ class Parser(metaclass=_Parser):
             maybe_func = True
 
         this: t.Optional[exp.Expression] = None
-        values: t.Optional[t.List[t.Optional[exp.Expression]]] = None
+        values: t.Optional[t.List[exp.Expression]] = None
 
         if nested and self._match(TokenType.LT):
             if is_struct:
                 expressions = self._parse_csv(self._parse_struct_types)
             else:
                 expressions = self._parse_csv(
-                    lambda: self._parse_types(check_func=check_func, schema=schema)
+                    lambda: self._parse_types(
+                        check_func=check_func, schema=schema, allow_identifiers=allow_identifiers
+                    )
                 )
 
             if not self._match(TokenType.GT):
@@ -3355,7 +3497,7 @@ class Parser(metaclass=_Parser):
         upper = this.upper()
 
         parser = self.NO_PAREN_FUNCTION_PARSERS.get(upper)
-        if optional_parens and parser:
+        if optional_parens and parser and token_type not in self.INVALID_FUNC_NAME_TOKENS:
             self._advance()
             return parser(self)
 
@@ -3442,7 +3584,9 @@ class Parser(metaclass=_Parser):
         index = self._index
 
         if self._match(TokenType.L_PAREN):
-            expressions = self._parse_csv(self._parse_id_var)
+            expressions = t.cast(
+                t.List[t.Optional[exp.Expression]], self._parse_csv(self._parse_id_var)
+            )
 
             if not self._match(TokenType.R_PAREN):
                 self._retreat(index)
@@ -3481,14 +3625,14 @@ class Parser(metaclass=_Parser):
         if not self._match(TokenType.L_PAREN):
             return this
 
-        args = self._parse_csv(
-            lambda: self._parse_constraint()
-            or self._parse_column_def(self._parse_field(any_token=True))
-        )
+        args = self._parse_csv(lambda: self._parse_constraint() or self._parse_field_def())
 
         self._match_r_paren()
         return self.expression(exp.Schema, this=this, expressions=args)
 
+    def _parse_field_def(self) -> t.Optional[exp.Expression]:
+        return self._parse_column_def(self._parse_field(any_token=True))
+
     def _parse_column_def(self, this: t.Optional[exp.Expression]) -> t.Optional[exp.Expression]:
         # column defs are not really columns, they're identifiers
         if isinstance(this, exp.Column):
@@ -3499,7 +3643,18 @@ class Parser(metaclass=_Parser):
         if self._match_text_seq("FOR", "ORDINALITY"):
             return self.expression(exp.ColumnDef, this=this, ordinality=True)
 
-        constraints = []
+        constraints: t.List[exp.Expression] = []
+
+        if not kind and self._match(TokenType.ALIAS):
+            constraints.append(
+                self.expression(
+                    exp.ComputedColumnConstraint,
+                    this=self._parse_conjunction(),
+                    persisted=self._match_text_seq("PERSISTED"),
+                    not_null=self._match_pair(TokenType.NOT, TokenType.NULL),
+                )
+            )
+
         while True:
             constraint = self._parse_column_constraint()
             if not constraint:
@@ -3553,7 +3708,7 @@ class Parser(metaclass=_Parser):
         identity = self._match_text_seq("IDENTITY")
 
         if self._match(TokenType.L_PAREN):
-            if self._match_text_seq("START", "WITH"):
+            if self._match(TokenType.START_WITH):
                 this.set("start", self._parse_bitwise())
             if self._match_text_seq("INCREMENT", "BY"):
                 this.set("increment", self._parse_bitwise())
@@ -3580,11 +3735,13 @@ class Parser(metaclass=_Parser):
 
     def _parse_not_constraint(
         self,
-    ) -> t.Optional[exp.NotNullColumnConstraint | exp.CaseSpecificColumnConstraint]:
+    ) -> t.Optional[exp.Expression]:
         if self._match_text_seq("NULL"):
             return self.expression(exp.NotNullColumnConstraint)
         if self._match_text_seq("CASESPECIFIC"):
             return self.expression(exp.CaseSpecificColumnConstraint, not_=True)
+        if self._match_text_seq("FOR", "REPLICATION"):
+            return self.expression(exp.NotForReplicationColumnConstraint)
         return None
 
     def _parse_column_constraint(self) -> t.Optional[exp.Expression]:
@@ -3729,7 +3886,7 @@ class Parser(metaclass=_Parser):
         bracket_kind = self._prev.token_type
 
         if self._match(TokenType.COLON):
-            expressions: t.List[t.Optional[exp.Expression]] = [
+            expressions: t.List[exp.Expression] = [
                 self.expression(exp.Slice, expression=self._parse_conjunction())
             ]
         else:
@@ -3844,17 +4001,17 @@ class Parser(metaclass=_Parser):
 
         if not self._match(TokenType.ALIAS):
             if self._match(TokenType.COMMA):
-                return self.expression(
-                    exp.CastToStrType, this=this, expression=self._parse_string()
-                )
-            else:
-                self.raise_error("Expected AS after CAST")
+                return self.expression(exp.CastToStrType, this=this, to=self._parse_string())
+
+            self.raise_error("Expected AS after CAST")
 
         fmt = None
         to = self._parse_types()
 
         if not to:
             self.raise_error("Expected TYPE after CAST")
+        elif isinstance(to, exp.Identifier):
+            to = exp.DataType.build(to.name, udt=True)
         elif to.this == exp.DataType.Type.CHAR:
             if self._match(TokenType.CHARACTER_SET):
                 to = self.expression(exp.CharacterSet, this=self._parse_var_or_string())
@@ -3908,7 +4065,7 @@ class Parser(metaclass=_Parser):
             if self._match(TokenType.COMMA):
                 args.extend(self._parse_csv(self._parse_conjunction))
         else:
-            args = self._parse_csv(self._parse_conjunction)
+            args = self._parse_csv(self._parse_conjunction)  # type: ignore
 
         index = self._index
         if not self._match(TokenType.R_PAREN) and args:
@@ -3991,10 +4148,10 @@ class Parser(metaclass=_Parser):
 
     def _parse_json_key_value(self) -> t.Optional[exp.JSONKeyValue]:
         self._match_text_seq("KEY")
-        key = self._parse_field()
-        self._match(TokenType.COLON)
+        key = self._parse_column()
+        self._match_set((TokenType.COLON, TokenType.COMMA))
         self._match_text_seq("VALUE")
-        value = self._parse_field()
+        value = self._parse_bitwise()
 
         if not key and not value:
             return None
@@ -4116,7 +4273,7 @@ class Parser(metaclass=_Parser):
         # Postgres supports the form: substring(string [from int] [for int])
         # https://www.postgresql.org/docs/9.1/functions-string.html @ Table 9-6
 
-        args = self._parse_csv(self._parse_bitwise)
+        args = t.cast(t.List[t.Optional[exp.Expression]], self._parse_csv(self._parse_bitwise))
 
         if self._match(TokenType.FROM):
             args.append(self._parse_bitwise())
@@ -4149,7 +4306,7 @@ class Parser(metaclass=_Parser):
             exp.Trim, this=this, position=position, expression=expression, collation=collation
         )
 
-    def _parse_window_clause(self) -> t.Optional[t.List[t.Optional[exp.Expression]]]:
+    def _parse_window_clause(self) -> t.Optional[t.List[exp.Expression]]:
         return self._match(TokenType.WINDOW) and self._parse_csv(self._parse_named_window)
 
     def _parse_named_window(self) -> t.Optional[exp.Expression]:
@@ -4216,8 +4373,7 @@ class Parser(metaclass=_Parser):
         if self._match_text_seq("LAST"):
             first = False
 
-        partition = self._parse_partition_by()
-        order = self._parse_order()
+        partition, order = self._parse_partition_and_order()
         kind = self._match_set((TokenType.ROWS, TokenType.RANGE)) and self._prev.text
 
         if kind:
@@ -4256,6 +4412,11 @@ class Parser(metaclass=_Parser):
 
         return window
 
+    def _parse_partition_and_order(
+        self,
+    ) -> t.Tuple[t.List[exp.Expression], t.Optional[exp.Expression]]:
+        return self._parse_partition_by(), self._parse_order()
+
     def _parse_window_spec(self) -> t.Dict[str, t.Optional[str | exp.Expression]]:
         self._match(TokenType.BETWEEN)
 
@@ -4377,14 +4538,14 @@ class Parser(metaclass=_Parser):
             self._advance(-1)
         return None
 
-    def _parse_except(self) -> t.Optional[t.List[t.Optional[exp.Expression]]]:
+    def _parse_except(self) -> t.Optional[t.List[exp.Expression]]:
         if not self._match(TokenType.EXCEPT):
             return None
         if self._match(TokenType.L_PAREN, advance=False):
             return self._parse_wrapped_csv(self._parse_column)
         return self._parse_csv(self._parse_column)
 
-    def _parse_replace(self) -> t.Optional[t.List[t.Optional[exp.Expression]]]:
+    def _parse_replace(self) -> t.Optional[t.List[exp.Expression]]:
         if not self._match(TokenType.REPLACE):
             return None
         if self._match(TokenType.L_PAREN, advance=False):
@@ -4393,7 +4554,7 @@ class Parser(metaclass=_Parser):
 
     def _parse_csv(
         self, parse_method: t.Callable, sep: TokenType = TokenType.COMMA
-    ) -> t.List[t.Optional[exp.Expression]]:
+    ) -> t.List[exp.Expression]:
         parse_result = parse_method()
         items = [parse_result] if parse_result is not None else []
 
@@ -4420,12 +4581,12 @@ class Parser(metaclass=_Parser):
 
         return this
 
-    def _parse_wrapped_id_vars(self, optional: bool = False) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_wrapped_id_vars(self, optional: bool = False) -> t.List[exp.Expression]:
         return self._parse_wrapped_csv(self._parse_id_var, optional=optional)
 
     def _parse_wrapped_csv(
         self, parse_method: t.Callable, sep: TokenType = TokenType.COMMA, optional: bool = False
-    ) -> t.List[t.Optional[exp.Expression]]:
+    ) -> t.List[exp.Expression]:
         return self._parse_wrapped(
             lambda: self._parse_csv(parse_method, sep=sep), optional=optional
         )
@@ -4439,7 +4600,7 @@ class Parser(metaclass=_Parser):
             self._match_r_paren()
         return parse_result
 
-    def _parse_expressions(self) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_expressions(self) -> t.List[exp.Expression]:
         return self._parse_csv(self._parse_expression)
 
     def _parse_select_or_expression(self, alias: bool = False) -> t.Optional[exp.Expression]:
@@ -4498,7 +4659,7 @@ class Parser(metaclass=_Parser):
 
         self._match(TokenType.COLUMN)
         exists_column = self._parse_exists(not_=True)
-        expression = self._parse_column_def(self._parse_field(any_token=True))
+        expression = self._parse_field_def()
 
         if expression:
             expression.set("exists", exists_column)
@@ -4549,13 +4710,16 @@ class Parser(metaclass=_Parser):
 
         return self.expression(exp.AddConstraint, this=this, expression=expression)
 
-    def _parse_alter_table_add(self) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_alter_table_add(self) -> t.List[exp.Expression]:
         index = self._index - 1
 
         if self._match_set(self.ADD_CONSTRAINT_TOKENS):
             return self._parse_csv(self._parse_add_constraint)
 
         self._retreat(index)
+        if not self.ALTER_TABLE_ADD_COLUMN_KEYWORD and self._match_text_seq("ADD"):
+            return self._parse_csv(self._parse_field_def)
+
         return self._parse_csv(self._parse_add_column)
 
     def _parse_alter_table_alter(self) -> exp.AlterColumn:
@@ -4576,7 +4740,7 @@ class Parser(metaclass=_Parser):
             using=self._match(TokenType.USING) and self._parse_conjunction(),
         )
 
-    def _parse_alter_table_drop(self) -> t.List[t.Optional[exp.Expression]]:
+    def _parse_alter_table_drop(self) -> t.List[exp.Expression]:
         index = self._index - 1
 
         partition_exists = self._parse_exists()
@@ -4619,6 +4783,9 @@ class Parser(metaclass=_Parser):
         self._match(TokenType.INTO)
         target = self._parse_table()
 
+        if target and self._match(TokenType.ALIAS, advance=False):
+            target.set("alias", self._parse_table_alias())
+
         self._match(TokenType.USING)
         using = self._parse_table()
 
@@ -4685,8 +4852,7 @@ class Parser(metaclass=_Parser):
         parser = self._find_parser(self.SHOW_PARSERS, self.SHOW_TRIE)
         if parser:
             return parser(self)
-        self._advance()
-        return self.expression(exp.Show, this=self._prev.text.upper())
+        return self._parse_as_command(self._prev)
 
     def _parse_set_item_assignment(
         self, kind: t.Optional[str] = None
@@ -4786,6 +4952,19 @@ class Parser(metaclass=_Parser):
         self._match_r_paren()
         return self.expression(exp.DictRange, this=this, min=min, max=max)
 
+    def _parse_comprehension(self, this: exp.Expression) -> exp.Comprehension:
+        expression = self._parse_column()
+        self._match(TokenType.IN)
+        iterator = self._parse_column()
+        condition = self._parse_conjunction() if self._match_text_seq("IF") else None
+        return self.expression(
+            exp.Comprehension,
+            this=this,
+            expression=expression,
+            iterator=iterator,
+            condition=condition,
+        )
+
     def _find_parser(
         self, parsers: t.Dict[str, t.Callable], trie: t.Dict
     ) -> t.Optional[t.Callable]: