(一)单个字段 1.查找表中多余的重复记录,根据(question_title)字段来判断 代码如下 复制代码 select * from questions where question_title in (select question_title from people group by question_title having count(question_title) > 1) 2.删除表中多余的重复记录,根据(question_title)字段来判断,只留有一个记录 代码如下 复制
1.首先看一下测试数据库的物理模型 2.测试所需要的Hibernate的jar包 3.数据库的sql /*==============================================================*/ /* DBMS name: MySQL 5.0 */ /* Created on: 2015/7/3 23:17:57 */ /*==============================================================*/ dr
--- //查找左边不存在数据,不能用 = '' SELECT m.uid FROM es_members m LEFT JOIN es_user_self_care_assessment u ON m.uid = u.user_id WHERE u.user_id IS NULL //合并起来查找 #(, )) as n 计算出年龄 SELECT m.uid,(, )) as n FROM es_members m LEFT JOIN es_user_self_care_assessment