摘要：
1、并集（UNION/UNION ALL）Oracle&SQLServer中用法一致UNION去重UNION ALL不去重-- 去重select * from tableaunionselect * from tableb-- 不去重select * from tableaunion allselect * from tableb2、交集（INTERSECT/EXISTS）Oracle&SQLServer中用法一致INTERSECT去重EXISTS不去重-- 去重select * from tableaintersectselect * from tableb-- 不去重sel 阅读全文
