[英]How to select rows that matches "multiple rows condition" in mysql
所以我创建了一个 sql fiddle 来更清楚地解释我的问题:
http://sqlfiddle.com/#!9/f35416
如您所见,我有 3 个表,其中 1 个链接其他 2 个。
table name: tags
---------------------
id | tag | value
---------------------
1 | color | green
2 | color | yellow
3 | color | red
4 | category | dress
5 | category | car
table name: product_tags_link
---------------------
product_id | tag_id
---------------------
1 | 1
1 | 5
2 | 1
3 | 2
3 | 5
4 | 4
5 | 4
5 | 1
table name: products
---------------------
id | name
---------------------
1 | green car
2 | yellow only
3 | yellow car
4 | dress only
5 | green dress
如果我可以得到任何具有“颜色”“绿色”和“类别”“汽车”的产品,我该怎么做?
我试着做:
select `ptl`.`product_id`
from `product_tags_link` as `ptl`
inner join `tags` on `tags`.`id` = `ptl`.`tag_id`
where ((`tags`.`tag` = "green") or (`tags`.`value` = "car"))
但它会返回其他绿色或汽车的产品。 将其更改为and
也不会返回任何内容。
我希望收到的是product_id: 1
有color:green
和category:car
加入所有 3 个表,按产品分组并在 HAVING 子句中设置条件:
select p.id, p.name
from products p
inner join product_tags_link l on l.product_id = p.id
inner join tags t on t.id = l.tag_id
where (t.tag = 'category' and t.value = 'car')
or (t.tag = 'color' and t.value = 'green')
group by p.id, p.name
having count(distinct t.tag) = 2
或者:
select p.id, p.name
from products p
inner join product_tags_link l on l.product_id = p.id
inner join tags t on t.id = l.tag_id
where (t.tag, t.value) in (('category', 'car'), ('color', 'green'))
group by p.id, p.name
having count(distinct t.tag) = 2
请参阅演示。
结果:
> id | name
> -: | :---
> 1 | test
我将省略连接表并按如下方式进行简单连接:
SELECT
p.id AS product_id
FROM
products p
LEFT JOIN
tags t ON p.id = t.id
WHERE
t.value = 'green'
AND p.name LIKE '%car%'
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