将两个具有不同列数的查询组合在一起

Question

我有两个查询要组合成单个输出,我不能使用UNIOn,因为它们具有不同的列数.

该表是ref用领域id refid cellid cat,它们都含有整数

查询1:查找每个唯一的总行数 cellid

SELECT cellid, COUNT(*) totalcount, cat FROM rel GROUP BY cellid

查询2:查找cat每个唯一的模式(最常见的值)cellid

SELECT cellid, cat
FROM rel t
GROUP BY cellid, cat
HAVING cat = (
SELECT cat
FROM rel
WHERE cellid = t.cellid
GROUP BY cat
ORDER BY COUNT(*) DESC, cat
LIMIT 1
)

举一个我想要做的例子,我想查询我的表

id | refid | cellid | cat
1  | 1     |  1     | 1
2  | 2     |  2     | 2
3  | 3     |  3     | 4
4  | 1     |  1     | 2
5  | 2     |  1     | 2
6  | 3     |  1     | 3
7  | 1     |  2     | 2
8  | 1     |  1     | 2

并返回

cellid | no_of_rows | Mode_of_cat
 1     |  5         |  2
 2     |  2         |  2
 3     |  1         |  4

Answer 1

这里最简单的解决方案就是编写一个查询来连接您已经拥有的两个结果集.您可以将查询结果存储在tmp表中并加入临时表,如下所示:

SELECT tmp1.cellid, tmp1.rows, tmp2.mode_cat FROM
(
    SELECT cellid, COUNT(*) AS rows
    FROM rel
    GROUP BY cellid
)tmp1
LEFT JOIN
(
    SELECT cellid, cat AS mode_cat
    FROM rel t
    GROUP BY cellid, cat
    HAVING cat = (
        SELECT cat
        FROM rel
        WHERE cellid = t.cellid
        GROUP BY cat
        ORDER BY COUNT(*) DESC, cat
        LIMIT 1
    )
)tmp2
ON tmp1.cellid = tmp2.cellid;