mysql - 在mysql查询中按父母获取所有孩子

Question

我有一个用户 ID 的表，managerid 如下：

id       manager
-------  -------
admin    (NULL)       
james    admin  
user     james  
workad   user   
creator  workad 

现在我想要一个用户 ID 的所有孩子（后代）。换句话说，对于用户 ID james ，我需要 children user, workad, creator。因为詹姆斯是最高父母（祖先）。是否有任何查询可以在 mysql 中获取这样的结果...在此先感谢。

Answer 1

为此，您需要有一个存储功能：

DELIMITER $$

DROP FUNCTION IF EXISTS `junk`.`GetFamilyTree` $$
CREATE FUNCTION `GetFamilyTree` (GivenID  VARCHAR(1024)) RETURNS varchar(1024) CHARSET latin1
DETERMINISTIC
BEGIN

    DECLARE rv,q,queue,queue_children,front_id VARCHAR(1024);
    DECLARE queue_length,pos INT;

    SET rv = '';
    SET queue = GivenID;
    SET queue_length = 1;

    WHILE queue_length > 0 DO
        SET front_id = queue;
        IF queue_length = 1 THEN
            SET queue = '';
        ELSE
            SET pos = LOCATE(',',queue) + 1;
            SET q = SUBSTR(queue,pos);
            SET queue = q;
        END IF;
        SET queue_length = queue_length - 1;

        SELECT IFNULL(qc,'') INTO queue_children
        FROM (SELECT GROUP_CONCAT(id) qc
        FROM Table1 WHERE manager = front_id) A;

        IF LENGTH(queue_children) = 0 THEN
            IF LENGTH(queue) = 0 THEN
                SET queue_length = 0;
            END IF;
        ELSE
            IF LENGTH(rv) = 0 THEN
                SET rv = queue_children;
            ELSE
                SET rv = CONCAT(rv,',',queue_children);
            END IF;
            IF LENGTH(queue) = 0 THEN
                SET queue = queue_children;
            ELSE
                SET queue = CONCAT(queue,',',queue_children);
            END IF;
            SET queue_length = LENGTH(queue) - LENGTH(REPLACE(queue,',','')) + 1;
        END IF;
    END WHILE;

    RETURN rv;
END $$

然后你可以打电话：

SELECT `id`, `manager`,GetFamilyTree(`id`) as children 
from Table1;

你也可以有过滤器：

SELECT `id`, `manager`,GetFamilyTree(`id`) as children 
from Table1 where `id` = 'james';

样品小提琴