如何加入多個表，其中一些（不是所有）列相同並返回每列的總和？

Question

我有多個表來跟蹤來自不同位置（即冷與暖）的信息，這些信息根據季節提供服務，並且需要創建位置的公司級別視圖。

查看 UNIONS 和 JOINS 的描述，看起來這些表必須具有相同數量的列或相同的列名。 我需要的是使用 PHP MySQL 提供相同列的總和以及唯一列的總和的結果。

 Table1 +-------+-------+-------+ | col-A | col-B | col-C | +-------+-------+-------+ | 2 | 8 | 5 | +-------+-------+-------+ | 1 | 9 | 7 | +-------+-------+-------+ | 3 | 2 | 3 | +-------+-------+-------+ Table2 +-------+-------+-------+ | col-1 | col-2 | col-3 | +-------+-------+-------+ | 2 | 1 | 6 | +-------+-------+-------+ | 5 | 5 | 4 | +-------+-------+-------+ | 2 | 7 | 3 | +-------+-------+-------+ Table3 +-------+-------+-------+-------+-------+-------+ | col-A | col-B | col-1 | col-2 | col-3 | col-4 | +-------+-------+-------+-------+-------+-------+ | 9 | 4 | 1 | 2 | 1 | 4 | +-------+-------+-------+-------+-------+-------+ | 2 | 6 | 6 | 8 | 3 | 6 | +-------+-------+-------+-------+-------+-------+ | 4 | 7 | 3 | 2 | 4 | 5 | +-------+-------+-------+-------+-------+-------+ Result Table +-------+-------+-------+-------+-------+-------+-------+ | col-A | col-B | col-C | col-1 | col-2 | col-3 | col-4 | +-------+-------+-------+-------+-------+-------+-------+ | 21 | 36 | 15 | 19 | 25 | 21 | 15 | +-------+-------+-------+-------+-------+-------+-------+

Answer 1

我認為這可以通過UNION來完成，如下所示：

SELECT SUM(`col-A`) AS 'Col-A',SUM(`col-b`) AS 'Col-B',
       SUM(`col-C`) AS 'Col-C',SUM(`col-1`) AS 'Col-1',
       SUM(`col-2`) AS 'Col-2',SUM(`col-3`) AS 'Col-3',SUM(`col-4`) AS 'Col-4' 
  FROM
(SELECT `col-A`,`col-b`,0 AS 'col-c',`col-1`,`col-2`,`col-3`,`col-4` FROM table_3 UNION
SELECT 0,0,0,`col-1`,`col-2`,`col-3`,0 FROM table_2 UNION
SELECT `col-A`,`col-b`,`col-C`, 0,0,0,0 FROM table_1 ) XX

因為 table_3 的列最多，所以我把它放在聯合的頂部。 以下查詢只需要在表中不存在該列的情況下填充0 （零）即可滿足聯合要求。