During query normalization, each object referenced in the SQL statement is validated. Query normalization verifies the objects referenced in the statement exist, and the datatypes are compatible with values in the statement.
select * from t1 where c1 = 10
The query normalization stage verifies that table t1 with a column named c1 exists in the system catalogs. It also verifies that the datatype of column c1 is compatible with the value 10. If the column’s datatype is datetime, for example, this statement is rejected.