选择多个标签 [英] Select with multiple tags

问题描述

我要修改以下查询，以便它要求当前元素上都存在两个标记.本质上要求tags_to_content中存在2行，并具有特定ID ...

I'm wanting to modify the following query so that it requires both tags exist on the current element. It's essentially requiring that 2 rows exist in tags_to_content with the specific ID...

SELECT
                content.id,
                content_text.content
            FROM content
            INNER JOIN tags_to_content ON (
                tags_to_content2.tag_id IN (1, 2) AND
                tags_to_content2.content_id = content.id
            )

推荐答案

解决此问题的常用方法是为每个所需的标签加入:

The usual way to solve this is to join for each of the desired tags:

SELECT
    content.id,
    content_text.content
FROM content
INNER JOIN tags_to_content t1 ON
    t1.content_id = content.id
INNER JOIN tags_to_content t2 ON
    t2.content_id = content.id
WHERE t1.tag_id = 1
AND t2.tag_id = 2

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