SQL exists 和not exists 替代in not in 问题
项目中遇到个超级长的sql。拷贝出来,用java 程序判断了下.总计字符长度 3464.里里外外的看的头晕.用oracle监测工具这里消耗时间特长.需要优化.
看了半天,牵涉业务逻辑,还是先改简单的吧.用exists 和not exists 替代in not in 。
A:
select a.user_id from tab_uum_users a where exists (select u.company_id from tab_uum_users u where u.user_id = 21800001900 and a.company_id = u.company_id) and not exists (select uuu.user_id from tab_uum_users uuu where a.user_id = uuu.user_id and uuu.user_id = 21800001900)
