mysql - 以编程方式删除重复行mysql

Question

我有一个表，该表已在某一点被截断，现在数据中有许多冲突。 在这篇文章中，我重命名了数据属性，但结构保持不变:

+-----------------+-----------+------------+-------------+-----------+-------------+
| parts_total_id  | parts_id  | title      | text        | value     | class       |
+-----------------+-----------+------------+-------------+-----------+-------------+
|            3000 |      1001 | Sub-Total: | $2400       | 2400.0000 | part_subtotal |
|            3001 |      1001 | Discount:  | $0          |    0.0000 | part_discount |
|            3002 |      1001 | Total:     | $2400       | 2400.0000 | part_total    |
|            5001 |      1001 | Subtotal   | $3200.00    | 3200.00   | part_subtotal |
|            5002 |      1001 | Total      | $3200.00    | 3200.0000 | part_total    |
+-----------------+-----------+------------+-------------+-----------+-------------+

我正在尝试删除较旧的记录(3000、3001、3002)，并且可以使用以下命令选择要使用“part_subtotal”和“part_total”类删除的记录，然后将它们移动到表中并运行删除基于 parts_total_id:

SELECT *
FROM parts_total
WHERE parts_total_id not in 
(
    SELECT max(parts_total_id)
    FROM parts_total
    WHERE class = 'part_total'
    GROUP BY parts_id
)
AND parts_total_id not in
(
    SELECT max(parts_total_id)
    FROM parts_total
    WHERE class = 'part_subtotal'
    GROUP BY parts_id
)

我遇到的问题是我还可能需要删除具有“part_discount”类的记录 3001 - 这可能并不总是存在，但通常位于part_subtotal 和part_total 之间。

Answer 1

最终使用了以下内容以及@Nick 的评论:

CREATE TEMPORARY TABLE IF NOT EXISTS parts_total_temp AS (
    SELECT *
    FROM parts_total
    WHERE parts_total_id not in 
    (
       SELECT max(parts_total_id)
       FROM parts_total
       WHERE class = 'part_total'
       GROUP BY parts_id
    )
    AND parts_total_id not in
    (
       SELECT max(parts_total_id)
       FROM parts_total
       WHERE class = 'part_subtotal'
       GROUP BY parts_id
    )
    AND parts_total_id < 
    (
       SELECT MAX(parts_total_id) 
       FROM parts_total p1 
       WHERE p1.parts_id = parts_total.parts_id 
       AND class = 'part_subtotal'
     )
);

DELETE pt1
FROM parts_total pt1
JOIN parts_total_temp pt2 ON pt1.parts_total_id = pt2.parts_total_id;

DROP TEMPORARY TABLE IF EXISTS parts_total_temp;