Truncate
1.Truncate Can be DDL Command.
2.it cannot be rollback.
3.we cann't use Where clause.
4.truncate=delete+commit so we cann't rollback.
5.truncate delete all record from the table.
6.truncate is a DDL command and cannot be rollbackand all
memory space is released back to server.
7.speed faster.
8.do not chcek constraint.
Delete
1.Delete Can be DML Command.
2.it can be rollback.
3.we can use Where clause.
4.delete=delete-- so we can be rollback.
5.delete delete record from the table.
6.truncate is a DDL command and can be rollback and all
memory space is not released back to server.
7.speed slow.
8. chcek constraint.

select is DML command...