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SQL：选择事务不在同一表内的条件的事务

sql

我有一张交易表：

Transactions
------------
id | account | type | date_time             | amount
----------------------------------------------------
 1 | 001     | 'R'  | '2012-01-01 10:01:00' | 1000
 2 | 003     | 'R'  | '2012-01-02 12:53:10' | 1500
 3 | 003     | 'A'  | '2012-01-03 13:10:01' | -1500
 4 | 002     | 'R'  | '2012-01-03 17:56:00' | 2000
 5 | 001     | 'R'  | '2012-01-04 12:30:01' | 1000
 6 | 002     | 'A'  | '2012-01-04 13:23:01' | -2000
 7 | 003     | 'R'  | '2012-01-04 15:13:10' | 3000
 8 | 003     | 'R'  | '2012-01-05 12:12:00' | 1250
 9 | 003     | 'A'  | '2012-01-06 17:24:01' | -1250

并且我希望选择所有特定类型（’R’）的商品，但不要立即（按照date_time字段的顺序）针对同一帐户提交另一种其他类型（’A’）交易的商品…

因此，在给出前面的示例的情况下，查询应引发以下行：

id | account |type  | date                  | amount
----------------------------------------------------
 1 | 001     | 'R'  | '2012-01-01 10:01:00' | 1000
 5 | 001     | 'R'  | '2012-01-04 12:30:01' | 1000
 7 | 003     | 'R'  | '2012-01-04 15:13:10' | 3000

（如您所见，第2行未显示，因为第3行“取消了” …第4行也被“第6行“取消了”；第7行出现了（即使帐户003属于已取消的第2行）
，这一次在第7行中不会被任何“ A”行取消；并且不会出现第8行（对于003帐户来说也是如此，因为现在该帐户被9取消了，也不会取消7，只是先前的一个一：8
…

我已经尝试过Joins，Where子句中的子查询，但是我真的不确定如何进行查询…

我尝试过的是：

尝试加入：

   SELECT trans.type as type,
          trans.amount as amount,
          trans.date_time as dt,
          trans.account as acct,
     FROM Transactions trans
INNER JOIN ( SELECT t.type AS type, t.acct AS acct, t.date_time AS date_time
               FROM Transactions t
              WHERE t.date_time > trans.date_time
           ORDER BY t.date_time DESC
          ) AS nextTrans
       ON nextTrans.acct = trans.acct
    WHERE trans.type IN ('R')
      AND nextTrans.type NOT IN ('A')
 ORDER BY DATE(trans.date_time) ASC

这引发了错误，因为我无法在MySQL中向JOIN引入外部值。

在以下位置尝试子查询：

   SELECT trans.type as type,
          trans.amount as amount,
          trans.date_time as dt,
          trans.account as acct,
     FROM Transactions trans
    WHERE trans.type IN ('R')
      AND trans.datetime <
          ( SELECT t.date_time AS date_time
               FROM Transactions t
              WHERE t.account = trans.account
           ORDER BY t.date_time DESC
          ) AS nextTrans
       ON nextTrans.acct = trans.acct

 ORDER BY DATE(trans.date_time) ASC

这是错误的，我可以在MySQL的WHERE中引入外部值，但是我无法设法找到正确过滤所需方法的方法。

重要编辑：

我设法实现了一个解决方案，但现在需要进行认真的优化。这里是：

SELECT *
  FROM (SELECT t1.*, tFlagged.id AS cancId, tFlagged.type AS cancFlag
          FROM transactions t1
     LEFT JOIN (SELECT t2.*
                  FROM transactions t2
              ORDER BY t2.date_time ASC ) tFlagged
            ON (t1.account=tFlagged.account
                  AND
                t1.date_time < tFlagged.date_time)
         WHERE t1.type = 'R'
      GROUP BY t1.id) tCanc
 WHERE tCanc.cancFlag IS NULL
    OR tCanc.cancFlag <> 'A'

我自己加入了表格，只是考虑到相同的帐户和不错的date_time。Join按date_time排序。按ID分组，我设法仅获得加入的第一个结果，该结果恰好是同一帐户的下一个交易。

然后在外部选择中，我将那些具有“ A”的内容过滤掉，因为这意味着下一个交易实际上是对它的取消。换句话说，如果同一个帐户没有下一个交易，或者下一个交易是“
R”，则该交易不会被取消，并且必须在结果中显示…

我懂了：

+----+---------+------+---------------------+--------+--------+----------+
| id | account | type | date_time           | amount | cancId | cancFlag |
+----+---------+------+---------------------+--------+--------+----------+
|  1 | 001     |   R  | 2012-01-01 10:01:00 |   1000 |      5 | R        |
|  5 | 001     |   R  | 2012-01-04 12:30:01 |   1000 |   NULL | NULL     |
|  7 | 003     |   R  | 2012-01-04 15:13:10 |   3000 |      8 | R        |
+----+---------+------+---------------------+--------+--------+----------+

它将每个交易与下一个交易及时关联到同一帐户，然后筛选出已取消的交易…成功！

正如我所说，现在的问题是优化。我的真实数据有很多行（因为期望通过时间来保存事务的表具有），并且对于现在约10,000行的表，此查询在1分44秒内得到了肯定的结果。我想连接就是问题……（对于那些在这里了解协议的人，我应该怎么做？在这里发起一个新问题，并将其发布为该问题的解决方案？或者只是在这里等待更多答案？）


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2021-04-22

共1个答案

小编典典

这是基于嵌套子查询的解决方案。首先，我添加了几行来处理更多案例。例如，事务10不应被事务12取消，因为事务11介于两者之间。

> select * from transactions order by date_time;
+----+---------+------+---------------------+--------+
| id | account | type | date_time           | amount |
+----+---------+------+---------------------+--------+
|  1 |       1 | R    | 2012-01-01 10:01:00 |   1000 |
|  2 |       3 | R    | 2012-01-02 12:53:10 |   1500 |
|  3 |       3 | A    | 2012-01-03 13:10:01 |  -1500 |
|  4 |       2 | R    | 2012-01-03 17:56:00 |   2000 |
|  5 |       1 | R    | 2012-01-04 12:30:01 |   1000 |
|  6 |       2 | A    | 2012-01-04 13:23:01 |  -2000 |
|  7 |       3 | R    | 2012-01-04 15:13:10 |   3000 |
|  8 |       3 | R    | 2012-01-05 12:12:00 |   1250 |
|  9 |       3 | A    | 2012-01-06 17:24:01 |  -1250 |
| 10 |       3 | R    | 2012-01-07 00:00:00 |   1250 |
| 11 |       3 | R    | 2012-01-07 05:00:00 |   4000 |
| 12 |       3 | A    | 2012-01-08 00:00:00 |  -1250 |
| 14 |       2 | R    | 2012-01-09 00:00:00 |   2000 |
| 13 |       3 | A    | 2012-01-10 00:00:00 |  -1500 |
| 15 |       2 | A    | 2012-01-11 04:00:00 |  -2000 |
| 16 |       2 | R    | 2012-01-12 00:00:00 |   5000 |
+----+---------+------+---------------------+--------+
16 rows in set (0.00 sec)

首先，创建一个查询以针对每笔交易获取“同一帐户中最近一笔交易的日期”：

SELECT t2.*,
       MAX(t1.date_time) AS prev_date
FROM transactions t1
JOIN transactions t2
ON (t1.account = t2.account
   AND t2.date_time > t1.date_time)
GROUP BY t2.account,t2.date_time
ORDER BY t2.date_time;

+----+---------+------+---------------------+--------+---------------------+
| id | account | type | date_time           | amount | prev_date           |
+----+---------+------+---------------------+--------+---------------------+
|  3 |       3 | A    | 2012-01-03 13:10:01 |  -1500 | 2012-01-02 12:53:10 |
|  5 |       1 | R    | 2012-01-04 12:30:01 |   1000 | 2012-01-01 10:01:00 |
|  6 |       2 | A    | 2012-01-04 13:23:01 |  -2000 | 2012-01-03 17:56:00 |
|  7 |       3 | R    | 2012-01-04 15:13:10 |   3000 | 2012-01-03 13:10:01 |
|  8 |       3 | R    | 2012-01-05 12:12:00 |   1250 | 2012-01-04 15:13:10 |
|  9 |       3 | A    | 2012-01-06 17:24:01 |  -1250 | 2012-01-05 12:12:00 |
| 10 |       3 | R    | 2012-01-07 00:00:00 |   1250 | 2012-01-06 17:24:01 |
| 11 |       3 | R    | 2012-01-07 05:00:00 |   4000 | 2012-01-07 00:00:00 |
| 12 |       3 | A    | 2012-01-08 00:00:00 |  -1250 | 2012-01-07 05:00:00 |
| 14 |       2 | R    | 2012-01-09 00:00:00 |   2000 | 2012-01-04 13:23:01 |
| 13 |       3 | A    | 2012-01-10 00:00:00 |  -1500 | 2012-01-08 00:00:00 |
| 15 |       2 | A    | 2012-01-11 04:00:00 |  -2000 | 2012-01-09 00:00:00 |
| 16 |       2 | R    | 2012-01-12 00:00:00 |   5000 | 2012-01-11 04:00:00 |
+----+---------+------+---------------------+--------+---------------------+
13 rows in set (0.00 sec)

使用它作为子查询，以使每个事务及其前身在同一行上。使用一些过滤条件提取出我们感兴趣的交易-即，其前身是被完全取消的“ R”交易的“ A”交易-

SELECT
  t3.*,transactions.*
FROM
  transactions
  JOIN
  (SELECT t2.*,
          MAX(t1.date_time) AS prev_date
   FROM transactions t1
   JOIN transactions t2
   ON (t1.account = t2.account
      AND t2.date_time > t1.date_time)
   GROUP BY t2.account,t2.date_time) t3
  ON t3.account = transactions.account
     AND t3.prev_date = transactions.date_time
     AND t3.type='A'
     AND transactions.type='R'
     AND t3.amount + transactions.amount = 0
  ORDER BY t3.date_time;


+----+---------+------+---------------------+--------+---------------------+----+---------+------+---------------------+--------+
| id | account | type | date_time           | amount | prev_date           | id | account | type | date_time           | amount |
+----+---------+------+---------------------+--------+---------------------+----+---------+------+---------------------+--------+
|  3 |       3 | A    | 2012-01-03 13:10:01 |  -1500 | 2012-01-02 12:53:10 |  2 |       3 | R    | 2012-01-02 12:53:10 |   1500 |
|  6 |       2 | A    | 2012-01-04 13:23:01 |  -2000 | 2012-01-03 17:56:00 |  4 |       2 | R    | 2012-01-03 17:56:00 |   2000 |
|  9 |       3 | A    | 2012-01-06 17:24:01 |  -1250 | 2012-01-05 12:12:00 |  8 |       3 | R    | 2012-01-05 12:12:00 |   1250 |
| 15 |       2 | A    | 2012-01-11 04:00:00 |  -2000 | 2012-01-09 00:00:00 | 14 |       2 | R    | 2012-01-09 00:00:00 |   2000 |
+----+---------+------+---------------------+--------+---------------------+----+---------+------+---------------------+--------+
4 rows in set (0.00 sec)

从上面的结果可以明显看出，我们已经快到了-我们已经确定了不需要的交易。使用LEFT JOIN我们可以将它们从整个交易集中过滤掉：

SELECT
  transactions.*
FROM
  transactions
LEFT JOIN
  (SELECT
     transactions.id
   FROM
     transactions
     JOIN
     (SELECT t2.*,
             MAX(t1.date_time) AS prev_date
      FROM transactions t1
      JOIN transactions t2
      ON (t1.account = t2.account
         AND t2.date_time > t1.date_time)
      GROUP BY t2.account,t2.date_time) t3
     ON t3.account = transactions.account
        AND t3.prev_date = transactions.date_time
        AND t3.type='A'
        AND transactions.type='R'
        AND t3.amount + transactions.amount = 0) t4
  USING(id)
  WHERE t4.id IS NULL
    AND transactions.type = 'R'
  ORDER BY transactions.date_time;

+----+---------+------+---------------------+--------+
| id | account | type | date_time           | amount |
+----+---------+------+---------------------+--------+
|  1 |       1 | R    | 2012-01-01 10:01:00 |   1000 |
|  5 |       1 | R    | 2012-01-04 12:30:01 |   1000 |
|  7 |       3 | R    | 2012-01-04 15:13:10 |   3000 |
| 10 |       3 | R    | 2012-01-07 00:00:00 |   1250 |
| 11 |       3 | R    | 2012-01-07 05:00:00 |   4000 |
| 16 |       2 | R    | 2012-01-12 00:00:00 |   5000 |
+----+---------+------+---------------------+--------+
2021-04-22