Question

cte有时可能是记忆力的。以下SQL在其他数据库存在内存问题之前效果很好。

如何使用派生表重现Row_Number Over Partition的任何想法。

表A包含工作电话。表B包含Id。我们必须将表A与表B联系起来，以便在表B中找到重复项;使用手机作为重复标准。

这个SQL有效。我只是希望看到使用派生表的建议。

;WITH cte
                 AS (SELECT Row_number() OVER (PARTITION BY a.WorkPhone ORDER BY b.id DESC ) AS
                            rownumber
                            ,
                            a.WorkPhone,
                            a.id
                     FROM   TableB B
                            JOIN TableA a
                              ON b.GroupofLeadsid = a.id
                     WHERE  b.GroupofLeads = @GroupofLeads
                            AND NOT a.WorkPhone IS NULL
                            AND a.WorkPhone <> '')

            UPDATE b
            SET    b.deleteflag = 1
            FROM   TableB b
                   JOIN cte t
                     ON b.id = t.id
            WHERE  b.GroupofLeads = @GroupofLeads
                   AND rownumber > 1

Answer 1

Update TableB
Set deleteflag = 1
From TableB As B
    Join    (
            Select Row_Number() Over ( Partition By A.WorkPhone Order By B.Id Desc ) As RowNum
                , A.WorkPhone, A.Id
                , B.Id
            From TableB As B1
                Join TableA As A1
                    On A1.id = B1.GroupOfLeadsId
            Where B1.GroupOfLeadsId = @GroupOfLeads
                And A.WorkPhone <> ''
            ) As CTE
        On CTE.Id = B.Id
Where CTE.RowNum > 1

另一种选择：

Update TableB
Set deleteflag = 1
Where Exists    (
                Select 1
                From    (
                        Select Row_Number() Over ( Partition By A.WorkPhone Order By B.Id Desc ) As RowNum
                            , B.Id
                        From TableB As B1
                            Join TableA As A1
                                On A1.id = B1.GroupOfLeadsId
                        Where B1.GroupOfLeadsId = @GroupOfLeads
                            And A.WorkPhone <> ''
                        ) As CTE
                Where CTE.RowNum > 1
                    And CTE.Id = TableB.Id
                )

仅使用派生表查找重复项

1 个答案: