Question

我有一个层次结构的数据库表，其成员类似于上述带有父母和孩子的数组（一个mlm结构/树）。表名是成员，表中的字段是上述数组中的元素（用户ID，引用ID，名称，用户名）。如何计算一个用户名的所有子代？让我们以有孩子的用户ID 5和有孩子的孩子ID为例。我希望一个sql代码为所有儿童和儿童儿童的用户ID计数。谢谢！

Array
(
[0] => Array
    (
        [userid] => 3
        [refferenceid] => 4
        [name] => Bandil
        [surname] => Kazim
    )

[1] => Array
    (
        [userid] => 1
        [refferenceid] => 2
        [name] => Zarki
        [surname] => Andrew
    )

[2] => Array
    (
        [userid] => 5
        [refferenceid] => 1
        [name] => Mirko
        [surname] => Paul
    )

[3] => Array
    (
        [userid] => 2390189598
        [refferenceid] => 5
        [name] => Matias
        [surname] => Clark
    )

[4] => Array
    (
        [userid] => 4
        [refferenceid] => 
        [name] => Duncan
        [surname] => Christoph
    )

[5] => Array
    (
        [userid] => 2
        [refferenceid] => 3
        [name] => Zar
        [surname] => Jamal
    )

[6] => Array
    (
        [userid] => 123123
        [refferenceid] => 5
        [name] => Victor
        [surname] => Dobrinski
    )

[7] => Array
    (
        [userid] => 9
        [refferenceid] => 2390189598
        [name] => Slav
        [surname] => Jorgasen
    )

[8] => Array
    (
        [userid] => 4057926110
        [refferenceid] => 5
        [name] => Joseph
        [surname] => Vladinski
    )

[9] => Array
    (
        [userid] => 10
        [refferenceid] => 2390189598
        [name] => Jala
        [surname] => David
    )

[10] => Array
    (
        [userid] => 7568954902
        [refferenceid] => 4057926110
        [name] => ohn
        [surname] => macaron
    )

)

Answer 1

如果REFFERENCEID是父亲的ID，这是一种方式

SELECT REFFERENCEID, COUNT(*)
FROM
(SELECT USERID, REFFERENCEID FROM MEMBERS
WHERE REFFERENCEID IS NOT NULL
UNION
SELECT B.USERID AS USERID, A.REFFERENCEID AS REFFERENCEID
FROM MEMBERS A
LEFT JOIN MEMBERS B
ON A.USERID=B.REFFERENCEID
WHERE B.USERID IS NOT NULL AND A.REFFERENCEID IS NOT NULL) TOT
GROUP BY REFFERENCEID;

结果是每个REFFERENCEID的儿子和侄子的数量；如果您想通过联合使用的两个集合上的REFFERENCEID来知道儿子的数目和侄子的数目。

分层数据库表中的SQL Count子级

1 个答案: