php - mysql查询，两张表。仅当值存在于其他表中时才选择

Question

我有两个表，选项和产品。我想从选项中选择所有选项，但前提是 options.id 存在于任何产品列中。这是我的两个表:

选项表:

id        option         value

1       'kategorija'    'Muški'
2       'kategorija'    'Ženski'
3       'kategorija'    'Dječji'
4       'brand'         'Casio'
5       'brand'         'Lorus'
6       'brand'         'Seiko'
7       'brand'         'Citizen'
8       'mehanizam'     'Quartz'
9       'mehanizam'     'Automatik'
10      'mehanizam'     'Eco-Drive'
11      'brojcanik'     'Analogni'
12      'brojcanik'     'Digitalni'
13      'grupa'         'Satovi'
14      'grupa'         'Naocale'

和第二个表产品:

 id     grupa   brand    mehanizam  brojcanik   kategorija  

10380   '13'     '4'        '8'        '11'         '2'
10560   '13'     '4'        '9'        '12'         '1'
11100   '13'     '6'        '8'        '11'         '2'
12380   '14'     '7'        '8'        '11'         '2'
12490   '13'     '6'        '9'        '11'         '1'
15720   '14'     '6'        '9'        '12'         '1'
16550   '14'     '5'        '8'        '12'         '3'

我的查询尝试:

SELECT * FROM options WHERE EXISTS( SELECT 1 FROM products WHERE grupa="14" AND brand=options.id OR mehanizam=options.id OR brojcanik=options.id OR kategorija=options.id)

结果应该是:

Array
(
    [0] => Array
        (
            [id] => 14
            [option] => grupa
            [value] => Naocale
        )

    [1] => Array
        (
            [id] => 7
            [option] => brand
            [value] => Citizen
        )

    [2] => Array
        (
            [id] => 8
            [option] => mehanizam
            [value] => Quartz
        )

    [3] => Array
        (
            [id] => 11
            [option] => brojcanik
            [value] => Analogni
        )

    [4] => Array
        (
            [id] => 2
            [option] => kategorija
            [value] => Zenski
        )
)

对于产品 ID 12380 的一行，这是 grupa 14 的数组。对于在产品行中找到 grupa 14 的其余产品，数组应该继续。我不知道这是否仅适用于 mysql 查询。如果不可能，我将不得不与 php 进行比较，这是我试图避免的。

谢谢

Answer 1

根据您的说法，

I want to select all from options but only if options.id exists in any of the products columns.

您可以在子查询中使用 UNION ALL 组合所有值，并将结果与​​表 options 连接。

SELECT  DISTINCT a.*
FROM    options a
        INNER JOIN
        (
            SELECT  brand col FROM products WHERE grupa = 14
            UNION ALL
            SELECT  mehanizam col FROM products WHERE grupa = 14
            UNION ALL
            SELECT  brojcanik col FROM products WHERE grupa = 14
            UNION ALL
            SELECT  kategorija col FROM products WHERE grupa = 14
        ) b ON a.id = b.col

---

更好的方法，

SELECT  * 
FROM    options a
WHERE   EXISTS
        ( 
            SELECT  1 
            FROM    products b
            WHERE   b.grupa = '14' AND 
                    a.ID IN (brand, mehanizam, brojcanik, kategorija)
        )