Fix(tsql)!: treat GO as command (#4978)

Author: georgesittas

sqlglot/dialects/tsql.py

@@ -511,6 +511,7 @@ class Tokenizer(tokens.Tokenizer):
             "DECLARE": TokenType.DECLARE,
             "EXEC": TokenType.COMMAND,
             "FOR SYSTEM_TIME": TokenType.TIMESTAMP_SNAPSHOT,
+            "GO": TokenType.COMMAND,
             "IMAGE": TokenType.IMAGE,
             "MONEY": TokenType.MONEY,
             "NONCLUSTERED INDEX": TokenType.INDEX,

tests/dialects/test_tsql.py

@@ -17,6 +17,8 @@ def test_tsql(self):
         # tsql allows .. which means use the default schema
         self.validate_identity("SELECT * FROM a..b")
 
+        self.validate_identity("GO").assert_is(exp.Command)
+        self.validate_identity("SELECT go").selects[0].assert_is(exp.Column)
         self.validate_identity("CREATE view a.b.c", "CREATE VIEW b.c")
         self.validate_identity("DROP view a.b.c", "DROP VIEW b.c")
         self.validate_identity("ROUND(x, 1, 0)")