mysql - 输出WHERE子句中的子选择数据

Question

我有类似这样的 SQL 查询，它运行得非常完美:

SELECT a.id AS thingId
FROM t1 a
JOIN t2 z
ON z.refId = a.id
WHERE z.category IN (
    SELECT y.id 
    FROM t3 x
    JOIN t4 y
    ON x.category = y.id
    WHERE x.id = :a)    
LIMIT 1;

但是我还需要子选择中的一列，如何在输出中获取 x.data ？不幸的是，SELECT x.data, a.id AS thingId 不起作用。

Answer 1

使用另一个JOIN而不是IN

SELECT a.id AS thingId, x.data
FROM t1 AS a
JOIN t2 AS z ON z.refId = a.id
JOIN t4 AS y ON y.id = z.category
JOIN t3 AS x ON x.category = y.id
WHERE x.id = :a
LIMIT 1