php - 从 3 个表中选择 mysql 中的不同值

Question

我有三个表，tbl_first_product、tbl_third_product 和 tbl_fourth_product。

每个表有size1, size2, size3, size4, size5列。

例如，在tbl_first_product

id    size1    size2    size3    size4    size5

1      38       40       42       43        44
2      28       30       32       34        40

在 tbl_third_product 中

id    size1    size2    size3    size4    size5

1      30       32       40        0        0
2      28       30       32       34        0

在tbl_fourth_product

id    size1    size2    size3    size4    size5

1      20       26       40       44        0
2      28       30       32       34        40

我想合并所有这些表并获得不同的值，输出应该是，

20 26 28 30 32 34 38 40 42 43 44

有什么方法可以使用 mysql 和 php 获取此输出。

我尝试了很多。但没有结果。

提前致谢。

Answer 1

您可以对每个字段执行 UNION 并从中SELECT DISTINCT。

SELECT DISTINCT value
    FROM
   (SELECT size1 AS value FROM tbl_first_product

    UNION

    SELECT size2 AS value FROM tbl_first_product

    UNION

    SELECT size3 AS value FROM tbl_first_product

    UNION

    SELECT size4 AS value FROM tbl_first_product

    UNION

    SELECT size5 AS value FROM tbl_first_product

    UNION

    SELECT size1 AS value FROM tbl_third_product

    UNION

    SELECT size2 AS value FROM tbl_third_product

    UNION

    SELECT size3 AS value FROM tbl_third_product

    UNION

    SELECT size4 AS value FROM tbl_third_product

    UNION

    SELECT size5 AS value FROM tbl_third_product

    UNION

    SELECT size1 AS value FROM tbl_fourth_product

    UNION

    SELECT size2 AS value FROM tbl_fourth_product

    UNION

    SELECT size3 AS value FROM tbl_fourth_product

    UNION

    SELECT size4 AS value FROM tbl_fourth_product

    UNION

    SELECT size5 AS value FROM tbl_fourth_product) T
    WHERE value <> 0

希望这对您有所帮助。