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 。

为每个表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

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

是否有任何方法可以使用mysql和php获得此输出。

我试了很多 但是没有结果。

提前致谢。

Answer 1

您可以对每个字段进行UNION，然后从中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

希望这可以帮助。