如何找出資料表中重複的資料

如何找出資料表中重複的資料？

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也只要簡短的一行指令， 以下範例為找出重複出現超過一次的資料/
SELECT Calumn_Name,COUNT(*)
FROM Table_Name GROUP BY Calumn_Name HAVING COUNT(*) > 1

還有其他進階的用法，只是稍微修改一下就可以 （來源網址）

1. 查閱資料表中多餘的重複記錄，重複記錄是根據單個欄位（peopleId）來判斷

select * from people  where peopleId in
(select peopleId from people group by peopleId having count(peopleId) > 1)


1. 刪除表中多餘的重複記錄，重複記錄是根據單個欄位（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)


1. 查閱資料表中多餘的重複記錄（多個欄位）

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


1. 刪除表中多餘的重複記錄（多個欄位），只留有rowid最小的記錄

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)


1. 查閱資料表中多餘的重複記錄（多個欄位），不包含rowid最小的記錄

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)