sql 查出一張表中重復的所有記錄數據
1.表中有id和name 兩個字段，查詢出name重復的所有數據
| select * from xi a where (a.username) in (select username from xi group by username having count(*) > 1) |
2、查詢出所有數據進行分組之后，和重復數據的重復次數的查詢數據，先列下：
| select count(username) as '重復次數',username from xi group by username having count(*)>1 order by username desc |
3、一下為 查看別人的 結果，現列下：查詢及刪除重復記錄的方法大全
1、查找表中多余的重復記錄，重復記錄是根據單個字段（peopleId）來判斷
| select * from peoplewhere peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) |
2、刪除表中多余的重復記錄，重復記錄是根據單個字段（peopleId）來判斷，只留有rowid最小的記錄
| 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) |
3、查找表中多余的重復記錄（多個字段）
| select * from vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1) |
4、刪除表中多余的重復記錄（多個字段），只留有rowid最小的記錄
| delete from vitae awhere (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、查找表中多余的重復記錄（多個字段），不包含rowid最小的記錄
| select * from vitae awhere (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) |
(二)
比方說
在A表中存在一個字段“name”，
而且不同記錄之間的“name”值有可能會相同，
現在就是需要查詢出在該表中的各記錄之間，“name”值存在重復的項；
| Select Name,Count(*) From A Group By Name Having Count(*) > 1 |
如果還查性別也相同大則如下:
| Select Name,sex,Count(*) From A Group By Name,sex Having Count(*) > 1 |
(三)
方法一
| declare @max integer,@id integerdeclare cur_rows cursor local for select 主字段,count(*) from 表名 group by 主字段 having count(*) >;open cur_rows fetch cur_rows into @id,@maxwhile @@fetch_status=0begin select @max = @max -1 set rowcount @max delete from 表名 where 主字段 = @idfetch cur_rows into @id,@maxendclose cur_rowsset rowcount 0 |
