查找重复记录的高效查询 [英] Efficient query for finding duplicate records

问题描述

我需要查询一个表中的重复存款记录，其中在某个时间窗口内在一个现金终端进行的两次相同金额的存款被视为重复记录.我现在已经开始处理一个查询，但如果您就正确"执行此操作提出任何建议或建议，我将不胜感激.

I need to query a table for duplicate deposit records, where two deposits made at one cash terminal, for the same amount, within a certain time window, are considered duplicate records. I've started working on a query now, but I would appreciate any advice or suggestions on doing this 'properly'.

推荐答案

通常，您会对同一个表进行自联接，并将重复"条件放在联接条件中.

Generally, you'd do a self join to the same table, and put your "duplicate" criteria in the join conditions.

例如

SELECT
    *
FROM
    Transactions t1
        inner join
    Transactions t2
        on
            t1.Terminal = t2.Terminal and
            t1.Amount = t2.Amount and
            DATEDIFF(minute,t2.TransactionDate,t1.TransactionDate) between 0 and 10 and
            t1.TransactionID > t2.TransactionID /* prevent matching the same row */

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