Fix(optimizer): make normalize_identifiers identifier conversion more…

… lenient (#2478)

sqlglot/optimizer/normalize_identifiers.py

@@ -2,7 +2,7 @@
 
 import typing as t
 
-from sqlglot import exp, parse_one
+from sqlglot import ParseError, exp, parse_one
 from sqlglot._typing import E
 from sqlglot.dialects.dialect import Dialect, DialectType
 
@@ -49,7 +49,10 @@ def normalize_identifiers(expression, dialect=None):
         The transformed expression.
     """
     if isinstance(expression, str):
-        expression = parse_one(expression, dialect=dialect, into=exp.Identifier)
+        try:
+            expression = parse_one(expression, dialect=dialect, into=exp.Identifier)
+        except ParseError:
+            expression = exp.to_identifier(expression)
 
     dialect = Dialect.get_or_raise(dialect)
 

tests/test_optimizer.py

@@ -271,6 +271,8 @@ def test_normalize_identifiers(self):
             set_dialect=True,
         )
 
+        self.assertEqual(optimizer.normalize_identifiers.normalize_identifiers("a%").sql(), '"a%"')
+
     def test_pushdown_projection(self):
         self.check_file("pushdown_projections", pushdown_projections, schema=self.schema)