[英]SQL to delete the duplicates in a table
I have a table transaction which has duplicates.我有一个有重复的表事务。 i want to keep the record that had minimum id and delete all the duplicates based on four fields DATE, AMOUNT, REFNUMBER, PARENTFOLDERID.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。 I wrote this query but i am not sure if this can be written in an efficient way.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。 Do you think there is a better way?你认为有更好的方法吗? I am asking because i am worried about the run time.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)
It would probably be more efficient to do something like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 )
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);
I will try like this我会这样尝试
I would try something like this: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
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.