MySQL中查询、删除重复记录的方法大全

select * from zyj_dxzxyh where name in (select name from zyj_dxzxyh group by name having count(name) > 1)

# 查找表中多余的重复记录

# 选择 * 所有列 从表zyj_dxzxyh 

# where 条件过滤  name 列 是字句

# 字句：选择name列   group by 分组排序列 name ；  having count(name) 计数 name列相同的行的个是大于1 

delete from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

# 删除表中多余的重复记录

select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

# 查找表中多余的重复记录

delete from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1) and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

# 删除表中多余的重复记录（多个字段），只留有rowid最小的记录

select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1) and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

# 查找表中多余的重复记录（多个字段），不包含rowid最小的记录

#-------------------------------------- 补充 -------------------------------------- 

select distinct * from tableName

就可以得到无重复记录的结果集。

如果该表需要删除重复的记录（重复记录保留1条），可以按以下方法删除

select distinct * into #Tmp from tableName

drop table tableName

select * into tableName from #Tmp

drop table #Tmp

发生这种重复的原因是表设计不周产生的，增加唯一索引列即可解决。

2、这类重复问题通常要求保留重复记录中的第一条记录，操作方法如下

假设有重复的字段为Name,Address，要求得到这两个字段唯一的结果集

select identity(int,1,1) as autoID, * into #Tmp from tableName

select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID

select * from #Tmp where autoID in(select autoID from #tmp2)