Fix(parser): ensure identifiers aren't treated as NO_PAREN_FUNCTIONS (#…

…2056)

* Fix(parser): ensure identifiers aren't treated as NO_PAREN_FUNCTIONS

* Create a set with tokens that can't be used as no paren func names

sqlglot/parser.py

@@ -728,6 +728,11 @@ 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 = {
@@ -3356,7 +3361,7 @@ def _parse_function(
         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)
 

tests/fixtures/identity.sql

@@ -855,3 +855,4 @@ SELECT * FROM (tbl1 CROSS JOIN (SELECT * FROM tbl2) AS t1)
 /* comment1 */ DELETE FROM x /* comment2 */ WHERE y > 1
 /* comment */ CREATE TABLE foo AS SELECT 1
 SELECT next, transform, if
+SELECT "any", "case", "if", "next"

tests/test_parser.py

@@ -216,6 +216,9 @@ def test_parse_errors(self):
         with self.assertRaises(ParseError):
             parse_one("IF(a > 0)")
 
+        with self.assertRaises(ParseError):
+            parse_one("SELECT CASE FROM x")
+
         with self.assertRaises(ParseError):
             parse_one("WITH cte AS (SELECT * FROM x)")