Refactor(clickhouse): override _parse_property_assignment to handle null engine

Author: georgesittas

sqlglot/dialects/clickhouse.py

@@ -27,6 +27,9 @@
 from sqlglot.tokens import Token, TokenType
 from sqlglot.generator import unsupported_args
 
+if t.TYPE_CHECKING:
+    from sqlglot._typing import E
+
 DATEΤΙΜΕ_DELTA = t.Union[exp.DateAdd, exp.DateDiff, exp.DateSub, exp.TimestampSub, exp.TimestampAdd]
 
 
@@ -500,9 +503,6 @@ class Parser(parser.Parser):
 
         PROPERTY_PARSERS = parser.Parser.PROPERTY_PARSERS.copy()
         PROPERTY_PARSERS.pop("DYNAMIC")
-        PROPERTY_PARSERS["ENGINE"] = lambda self: self._parse_property_assignment(
-            exp.EngineProperty, anonymous_func=True
-        )
 
         NO_PAREN_FUNCTION_PARSERS = parser.Parser.NO_PAREN_FUNCTION_PARSERS.copy()
         NO_PAREN_FUNCTION_PARSERS.pop("ANY")
@@ -571,6 +571,12 @@ class Parser(parser.Parser):
             TokenType.L_BRACE: lambda self: self._parse_query_parameter(),
         }
 
+        def _parse_property_assignment(self, exp_class: t.Type[E], **kwargs: t.Any) -> E:
+            this = super()._parse_property_assignment(exp_class, **kwargs)
+            if isinstance(this, exp.EngineProperty) and isinstance(this.this, exp.Null):
+                this.this.replace(exp.Anonymous(this="Null"))
+            return this
+
         # https://clickhouse.com/docs/en/sql-reference/statements/create/function
         def _parse_user_defined_function_expression(self) -> t.Optional[exp.Expression]:
             return self._parse_lambda()

sqlglot/parser.py

@@ -2196,22 +2196,18 @@ def _parse_stored(self) -> t.Union[exp.FileFormatProperty, exp.StorageHandlerPro
             ),
         )
 
-    def _parse_unquoted_field(self, anonymous_func: bool = False) -> t.Optional[exp.Expression]:
-        field = self._parse_field(anonymous_func=anonymous_func)
+    def _parse_unquoted_field(self) -> t.Optional[exp.Expression]:
+        field = self._parse_field()
         if isinstance(field, exp.Identifier) and not field.quoted:
             field = exp.var(field)
 
         return field
 
-    def _parse_property_assignment(
-        self, exp_class: t.Type[E], anonymous_func: bool = False, **kwargs: t.Any
-    ) -> E:
+    def _parse_property_assignment(self, exp_class: t.Type[E], **kwargs: t.Any) -> E:
         self._match(TokenType.EQ)
         self._match(TokenType.ALIAS)
 
-        return self.expression(
-            exp_class, this=self._parse_unquoted_field(anonymous_func=anonymous_func), **kwargs
-        )
+        return self.expression(exp_class, this=self._parse_unquoted_field(), **kwargs)
 
     def _parse_properties(self, before: t.Optional[bool] = None) -> t.Optional[exp.Properties]:
         properties = []