-- --标准sql方法：mysql、sql server-- -- 查询重复 方法一 select t.id,t.name from test t join( select min(id) id,name from test group by name having(count(1)>1) ) tt on t.id>tt.id and t.name=tt.name -- 查询重复 方法二 select * from test where exists( select * from ( select min(id) id,name from test group by name having(count(1)>1) ) as tt where test.id>tt.id and test.name=tt.name ) -- 删除重复 方法 delete from test where exists( select * from ( select min(id) id,name from test group by name having(count(1)>1) ) as tt where test.id>tt.id and test.name=tt.name ) -- --sql server方法---- -- 查询 select * from ( select ROW_NUMBER() over(partition by name order by id ) row,id,name from test ) t where t.row>1 -- 删除 delete from test where exists( select * from ( select ROW_NUMBER() over(partition by name order by id ) row,id,name from test ) t where t.row>1 and test.id=t.id )
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在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢 1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录 delete from people where peopleName in (select peopleName from people group by peopleName having count(peopleName) > 1) and peopleId not in (select min(peopleId) from people group by peopleName having count(peopleName)>1)
3、查找表中多余的重复记录（多个字段） select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录 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)
5、查找表中多余的重复记录（多个字段），不包含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)
6.消除一个字段的左边的第一位：
update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%'
7.消除一个字段的右边的第一位：
update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村'
8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录 update vitae set ispass=-1 where peopleId in (select peopleId from vitae group by peopleId
