MySQL 合并表格并将具有唯一行 ID 的多个列转置为非唯一行

Question

我正在尝试将多个 table 合并为一个，并通过将 table 从列转置为行来更改数据集的结构。我正在使用 MySQL.

我已经尝试了几天来找到一个智能解决方案，而无需手动将具有唯一 ID 的每一行转换为具有相同 ID 的多行。但是，我发现自己卡住了。

我当前的数据集：

Table一个：

ID    M1 amount    M2 amount    M3 amount
1234  0 543,00  0 000,00  0 321,00 
4566  0 321,00  0 012,00  0 345,00 
3311  0 000,00  0 000,00  0 312,00

Table二：

ID    M1 units  M2 units  M3 units
1234  30811 pc  46154 pc  38486 pc
4566  38486 pc  23078 pc  15411 pc
3311  23077 pc  34615 pc  7716 pc

我想要实现的是 table 具有以下结构：

ID    M    Units    Amounts
1234  1    30811 pc  0 543,00 
1234  2    46154 pc  0 000,00 
1234  3    38486 pc  0 321,00 
4566  1    38486 pc  0 321,00 
4566  2    23078 pc  0 012,00 
4566  3    15411 pc  0 345,00 
3311  1    23077 pc  0 000,00 
3311  2    34615 pc  0 000,00 
3311  3    7716 pc   0 312,00

非常感谢你对这个问题的帮助。

Answer 1

下面的 sql 脚本可以完成这项工作。使用 UNION ALL 我们将 Mx units 和 Mx amount 数据转换为行并将它们保存在 临时表 中。然后我们将它们加入 ID 和 M 列。

CREATE TEMPORARY TABLE tmp_t1 AS (
    SELECT *
    FROM (
        SELECT ID, `M1 amount` AS Amount, '1' AS M FROM t1
        UNION ALL
        (SELECT ID, `M2 amount` AS Amount, '2' AS M FROM t1)
        UNION ALL
        (SELECT ID, `M3 amount` AS Amount, '3' AS M FROM t1)
    ) AS x
    ORDER BY ID ASC
);

CREATE TEMPORARY TABLE tmp_t2 AS (
    SELECT *
    FROM (
        SELECT ID, `M1 units` AS Units, '1' AS M FROM t2
        UNION ALL
        (SELECT ID, `M2 units` AS Units, '2' AS M FROM t2)
        UNION ALL
        (SELECT ID, `M3 units` AS Units, '3' AS M FROM t2)
    ) AS x
    ORDER BY ID ASC
);

SELECT
    t1.ID,
    t1.M,
    t2.Units,
    t1.Amount
FROM
    tmp_t1 AS t1
INNER JOIN tmp_t2 AS t2 ON t1.ID = t2.ID AND t1.M = t2.M;

输出

+------+---+----------+-------------+
| ID   | M | Units    | Amount      |
+------+---+----------+-------------+
| 1234 | 1 | 30811 pc | 0 543,00 |
| 1234 | 2 | 46154 pc | 0 000,00 |
| 1234 | 3 | 38486 pc | 0 321,00 |
| 3311 | 1 | 23077 pc | 0 000,00 |
| 3311 | 2 | 34615 pc | 0 000,00 |
| 3311 | 3 | 7716 pc  | 0 312,00 |
| 4566 | 1 | 38486 pc | 0 321,00 |
| 4566 | 2 | 23078 pc | 0 012,00 |
| 4566 | 3 | 15411 pc | 0 345,00 |
+------+---+----------+-------------+

示例数据

DROP DATABASE IF EXISTS so_example;
CREATE DATABASE so_example;
USE so_example;

CREATE TABLE t1 (
    ID INT UNSIGNED NOT NULL PRIMARY KEY,
    `M1 amount` VARCHAR(255),
    `M2 amount` VARCHAR(255),
    `M3 amount` VARCHAR(255)
);

INSERT INTO t1 (ID, `M1 amount`, `M2 amount`, `M3 amount`) VALUES
('1234', '0 543,00', '0 000,00', '0 321,00'),
('4566', '0 321,00', '0 012,00', '0 345,00'),
('3311', '0 000,00', '0 000,00', '0 312,00');

CREATE TABLE t2 (
    ID INT UNSIGNED NOT NULL PRIMARY KEY,
    `M1 units` VARCHAR(255),
    `M2 units` VARCHAR(255),
    `M3 units` VARCHAR(255)
);

INSERT INTO t2 (ID, `M1 units`, `M2 units`, `M3 units`) VALUES
('1234', '30811 pc', '46154 pc', '38486 pc'),
('4566', '38486 pc', '23078 pc', '15411 pc'),
('3311', '23077 pc', '34615 pc', '7716 pc');

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