Mysql实例Mysql删除重复的数据 Mysql数据去重复

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MySQL数据库中查询重复数据MYSQL入门

select * from employee group by emp_name having count (*)>1;MYSQL入门

Mysql? 查询可以删除的重复数据MYSQL入门

select t1.* from employee t1 where (t1.emp_name) in (select t4.emp_name from (select t2.emp_name from employee t2 group by t2.emp_name having count(*)>1) t4) and t1.emp_id not in (select t5.emp_id from (select min(t3.emp_id) as emp_id from employee t3 group by t3.emp_name having count(*)>1) t5);MYSQL入门

Mysql? 删除重复的数据MYSQL入门

delete t1 from employee t1 where (t1.emp_name) in (select t4.emp_name from (select t2.emp_name from employee t2 group by t2.emp_name having count(*)>1) t4) and t1.emp_id not in (select t5.emp_id from (select min(t3.emp_id) as emp_id from employee t3 group by t3.emp_name having count(*)>1) t5);MYSQL入门

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