mysql查询从两组不同的表中各选择两列

Question

需要从两组不同的表中各选择两列。

现在我有两个不同的查询，但想知道是否有办法在一个查询中使用它

查询-1

 SELECT     
        BSM, DATE, HOUR, SUM(t.ATT), SUM(t.AVG_HLD)
    FROM (
        SELECT BSM, DATE, HOUR, ATT, AVG_HLD FROM t1 WHERE  ".$whereCondition." UNION ALL
        SELECT BSM, DATE, HOUR, ATT, AVG_HLD FROM t2 WHERE  ".$whereCondition." 
        ) t
    GROUP BY BSM, DATE, HOUR ";

查询 2

 SELECT     
        BSM, DATE, HOUR, SUM(s.M_ATT), SUM(s.M_AVG_HLD)
    FROM (
        SELECT BSM, DATE, HOUR, M_ATT, AVG_HLD FROM t3 WHERE    ".$whereCondition." UNION ALL
        SELECT BSM, DATE, HOUR, M_ATT, AVG_HLD FROM t4 WHERE    ".$whereCondition."
        ) s
    GROUP BY BSM, DATE, HOUR ";

如何将 Query-1 和 Query-2 结合起来......

 SELECT     
        BSM, DATE, HOUR, SUM(s.ATT), SUM(s.AVG_HLD), SUM(s.M_ATT), SUM(s.M_AVG_HLD)
    FROM (
        ** Whatever it is **
        ) 
    GROUP BY BSM, DATE, HOUR ";

Answer 1

对所有 4 个子查询创建一个 UNION，为来自另一对表的列插入 0 列。

SELECT BSM, DATE, HOUR, SUM(ATT) AS ATT, SUM(AVG_HLD) AS AVG_HLD, SUM(M_ATT) AS M_ATT, SUM(M_AVG_HLD) AS M_AVG_HLD
FROM (
        SELECT BSM, DATE, HOUR, ATT, AVG_HLD, 0 AS M_ATT, 0 AS M_AVG_HLD FROM t1 WHERE  ".$whereCondition." 
        UNION ALL
        SELECT BSM, DATE, HOUR, ATT, AVG_HLD, 0 AS M_ATT, 0 AS M_AVG_HLD FROM t2 WHERE  ".$whereCondition." 
        UNION ALL
        SELECT BSM, DATE, HOUR, 0 AS ATT, 0 AS AVG_HLD, M_ATT, M_AVG_HLD FROM t3 WHERE    ".$whereCondition." 
        UNION ALL
        SELECT BSM, DATE, HOUR, 0 AS ATT, 0 AS AVG_HLD, M_ATT, M_AVG_HLD FROM t4 WHERE    ".$whereCondition."
    ) u
GROUP BY BSM, DATE, HOUR