DB2 经验SQL语句

dmewy

1.   根据临时表的PK删除现有表的数据.(用exists 效率高.避免sub-query)
     1.1    delete from T1  where （pk1,pk2,pk3） in (select pk1,pk2,pk3 from T2)
     1.2    delete from t1 as x where exists (select pk from t2 as xx where x.pk=xx.pk)