clickhouse: fix parsing of Null engine (#5042)

* Fix: preserve non-participating joins in eliminate_join_marks rule fixes #5039

* clickhouse: fix parsing of Null engine

Fixes #5041

---------

Co-authored-by: George Sittas <[email protected]>

Author: pkit

sqlglot/dialects/clickhouse.py

@@ -500,6 +500,9 @@ 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")

sqlglot/parser.py

@@ -2196,18 +2196,22 @@ def _parse_stored(self) -> t.Union[exp.FileFormatProperty, exp.StorageHandlerPro
             ),
         )
 
-    def _parse_unquoted_field(self) -> t.Optional[exp.Expression]:
-        field = self._parse_field()
+    def _parse_unquoted_field(self, anonymous_func: bool = False) -> t.Optional[exp.Expression]:
+        field = self._parse_field(anonymous_func=anonymous_func)
         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], **kwargs: t.Any) -> E:
+    def _parse_property_assignment(
+        self, exp_class: t.Type[E], anonymous_func: bool = False, **kwargs: t.Any
+    ) -> E:
         self._match(TokenType.EQ)
         self._match(TokenType.ALIAS)
 
-        return self.expression(exp_class, this=self._parse_unquoted_field(), **kwargs)
+        return self.expression(
+            exp_class, this=self._parse_unquoted_field(anonymous_func=anonymous_func), **kwargs
+        )
 
     def _parse_properties(self, before: t.Optional[bool] = None) -> t.Optional[exp.Properties]:
         properties = []

tests/dialects/test_clickhouse.py

@@ -167,6 +167,7 @@ def test_clickhouse(self):
         self.validate_identity(
             "CREATE MATERIALIZED VIEW test_view ON CLUSTER '{cluster}' (id UInt8) ENGINE=AggregatingMergeTree() ORDER BY tuple() AS SELECT * FROM test_data"
         )
+        self.validate_identity("CREATE TABLE test (id UInt8) ENGINE=Null()")
         self.validate_identity(
             "CREATE MATERIALIZED VIEW test_view ON CLUSTER cl1 TO table1 AS SELECT * FROM test_data"
         )