mysql - 左连接上的mysql查询，其中有多个值

Question

这是我的 sql 数据提琴手http://sqlfiddle.com/#!2/63178/1。我的查询有什么问题吗？

SELECT DISTINCT curr.id,curr.curr_tittle, curr.curr_desc 
FROM  wp_curriculum curr LEFT JOIN (SELECT DISTINCT * FROM wp_curriculum_topic WHERE curr_topic IN (4,12)) AS A ON A.curr_id = curr.id ORDER BY A.id

Answer 1

如果您要从两个表中查找匹配行，则只需替换LEFT JOIN为INNER JOIN，否则您的 sql 查询将显示 LEFT JOIN 条件的预期结果。

使用 INNER JOIN 的 SQL 查询：

SELECT DISTINCT curr.id,curr.curr_tittle, curr.curr_desc FROM  wp_curriculum curr INNER JOIN (SELECT DISTINCT * FROM wp_curriculum_topic WHERE curr_topic IN (4,12)) AS A ON curr.id = A.curr_id ORDER BY A.id

Answer 2

您的查询按预期工作。会不会是你在混合 ID 和 CURR_ID？