Question

好的，我要做的是尝试从一个跨越4个独立列的表中获取唯一值。

例如，我有以下查询，可以在其中一列上正常工作..

SELECT 
    rest.cuisine1, c.name
FROM
    specials
    INNER JOIN restaurant AS rest ON specials.restaurantid=rest.id
    INNER JOIN cuisine AS c ON rest.cuisine1=c.id
WHERE
    dateend >= CURDATE()
AND
    (specials.state='VIC' OR specials.state = 'ALL') 
AND 
    specials.status = 1 
AND 
    rest.status = 1
GROUP BY
    c.id;

现在，rest.cuisine1是包含数据的列之一。正如预期的那样，此查询仅返回该列的唯一值。以下是返回内容的示例：

12 Cafe
18 Asian
29 Coffee

该表中还有3列，其中包括：

rest.cuisine2
rest.cuisine3
rest.cuisine4

我可以运行上面的查询4次（每列一次），然后通过PHP运行值，只从4个不同的结果集中获取唯一值，但是我想知道我是否能得到我想要的全部在一个查询中。

Answer 1

试试这个

 SELECT 
    rest.cuisine1, c.name ,rest.cuisine2 , rest.cuisine3, rest.cuisine4
FROM
    specials
    INNER JOIN restaurant AS rest ON specials.restaurantid=rest.id
    INNER JOIN cuisine AS c ON rest.cuisine1=c.id
            INNER JOIN cuisine AS c2 ON rest.cuisine2=c2.id
            INNER JOIN cuisine AS c3 ON rest.cuisine3=c3.id
            INNER JOIN cuisine AS c4 ON rest.cuisine4=c4.id
WHERE
    dateend >= CURDATE()
AND
    (specials.state='VIC' OR specials.state = 'ALL') 
AND 
    specials.status = 1 
AND 
    rest.status = 1
GROUP BY
    c.id;

Answer 2

这个答案是基于MahmoudGamal在评论中发表的答案，他因某些原因删除了该评论。

我使用了以下..

SELECT 
    c.id, c.name
FROM
    specials
    INNER JOIN restaurant AS rest ON specials.restaurantid=rest.id
    INNER JOIN cuisine AS c ON c.id IN (rest.cuisine1, rest.cuisine2, rest.cuisine3, rest.cuisine4)
WHERE
    dateend >= CURDATE()
AND
    (specials.state='VIC' OR specials.state = 'ALL') 
AND 
    specials.status = 1 
AND 
    rest.status = 1
GROUP BY
    c.id;

通过4个不同列的值获取唯一组

2 个答案: