1.Union will remove the duplicate rows from the result set while
2. Union wont allow the duplicates,where as unionall allows the duplicates.
3.Union all does'nt remove rows from the result
4.Union is callback , union all doesnt call back
2. Union wont allow the duplicates,where as unionall allows the duplicates.
3.Union all does'nt remove rows from the result
4.Union is callback , union all doesnt call back
No comments:
Post a Comment