sql去除重复数据

sql去除重复数据 用SQL语句,删除掉重复项只保留一条 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 having count(peopleId) 1)