sql語句查詢表中重復數據（多類型）

表名：hztj

字段名：edxzqhdm ,sdxzqhdm

1.查出某一列數據中重復的，以sdxzqhdm為例

select * from hztj a where (a.sdxzqhdm) in (select sdxzqhdm from hztj group by sdxzqhdm 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

select  count(sdxzqhdm) as '重復次數',sdxzqhdm from hztj group by sdxzqhdm having count(*)>1 order by sdxzqhdm desc

查詢及刪除重復記錄的方法

（1）查找表中多余的重復記錄，重復記錄是根據單個字段來判斷 ，如：

select * from hztj
where sdxzqhdm in (select sdxzqhdm from hztj group by sdxzqhdm having count(sdxzqhdm) > 1)

（2）刪除表中多余的重復記錄，重復記錄是根據單個字段來判斷，只留rowid最小的記錄

delete from hztj
where sdxzqhdm in (select sdxzqhdm from hzth group  by  sdxzqhdm having  count(sdxzqhdm) > 1)
and rowid not in (select min(rowid) from  hztj group by sdxzqhdm having count(sdxzqhdm)>1)

（3）查找表中多余的重復記錄（多個字段）

select * from hztj a
where (a.sdxzqhdm,a.edxzqhdm) in (select sdxzqhdm,edxzqhdm from hztj group by sdxzqhdm,edxzqhdm 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 hztj a
where (a.sdxzqhdm,a.edxzqhdm) in (select sdxzqhdm,edxzqhdm from hztj group by sdxzqhdm,edxzqhdm having count(*) > 1) 
and rowid not in (select min(rowid) from hztj group by sdxzqhdm,edxzqhdm 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 hztj a
where (a.sdxzqhdm,a.edxzqhdm) in  (select sdxzqhdm,edxzqhdm from hztj group by sdxzqhdm,edxzqhdm having count(*) > 1)
and rowid not in (select min(rowid) from hztj group by sdxzqhdm,edxzqhdm having count(*)>1)