;WITH x AS
(
SELECt id, gid, url, rn = ROW_NUMBER() OVER
(PARTITION BY gid, url ORDER BY id)
FROM dbo.table
)
SELECt id,gid,url FROM x WHERe rn = 1 – the rows you’ll keep
– SELECt id,gid,url FROM x WHERe rn > 1 – the rows you’ll delete
– DELETE x WHERe rn > 1; – do the delete
对第一个选择满意（表示您将保留的行）后，将其删除并取消对第二个选择的注释。对此表示满意后，它指示要删除的行，将其删除并取消注释该删除。
如果您不想删除数据，只需忽略
SELECT…下的注释行即可。
