SQL 删除表中的重复项

Question

我有一个有重复的表事务。 我想保留具有最小 ID 的记录，并根据四个字段 DATE、AMOUNT、REFNUMBER、PARENTFOLDERID 删除所有重复项。 我写了这个查询，但我不确定这是否可以用有效的方式编写。 你认为有更好的方法吗？ 我问是因为我担心运行时间。

DELETE FROM TRANSACTION
WHERE ID IN 
(SELECT FIT2.ID
FROM
(SELECT MIN(ID) AS ID, FIT.DATE, FIT.AMOUNT, FIT.REFNUMBER, FIT.PARENTFOLDERID
FROM EWORK.TRANSACTION FIT
GROUP BY FIT.DATE, FIT.AMOUNT , FIT.REFNUMBER, FIT.PARENTFOLDERID
HAVING COUNT(1)>1 and FIT.AMOUNT >0) FIT1,
EWORK.TRANSACTION FIT2

WHERE FIT1.DATE=FIT2.DATE AND
FIT1.AMOUNT=FIT2.AMOUNT AND
FIT1.REFNUMBER=FIT2.REFNUMBER AND 
FIT1.PARENTFOLDERID=FIT2.PARENTFOLDERID AND 
FIT1.ID<>FIT2.ID)

Answer 1

做类似的事情可能会更有效率

DELETE FROM transaction t1
 WHERE EXISTS( SELECT 1
                 FROM transaction t2
                WHERE t1.date = t2.date
                  AND t1.refnumber = t2.refnumber
                  AND t1.parentFolderId = t2.parentFolderId
                  AND t2.id > t1.id )

Answer 2

DELETE FROM transaction
      WHERE ID IN (
               SELECT ID
                 FROM (SELECT ID,
                          ROW_NUMBER () OVER (PARTITION BY  date
                                                          ,amount
                                                          ,refnumber
                                                          ,parentfolderid
                                                ORDER BY ID) rn
                                              FROM transaction)
                WHERE rn <> 1);

我会这样尝试

Answer 3

我会尝试这样的事情：

DELETE transaction 
FROM transaction
LEFT OUTER JOIN 
   (
       SELECT MIN(id) as id, date, amount, refnumber, parentfolderid 
       FROM transaction
      GROUP BY date, amount, refnumber, parentfolderid
   ) as validRows 
ON transaction.id = validRows.id
WHERE validRows.id IS NULL