最近做项目遇到地区查询问题,涉及递归,在java代码中处理发现效率较低,遂考虑使用sql递归
贴上一张表结构:
一、查询下级方法
CREATE FUNCTION getChildrenOrg (orgid INT) RETURNS VARCHAR (4000)
BEGIN
DECLARE oTemp VARCHAR (4000);
DECLARE oTempChild VARCHAR (4000);
SET oTemp = '';
SET oTempChild = CAST(orgid AS CHAR);
WHILE oTempChild IS NOT NULL DO
SET oTemp = CONCAT(oTemp, ',', oTempChild);
SELECT
GROUP_CONCAT(areaid) INTO oTempChild
FROM
area
WHERE
FIND_IN_SET(parentid, oTempChild) > 0;
END
WHILE;
RETURN oTemp;
END
调用方法(查询areaid为620000(甘肃)的地区的全部下级)
SELECT
*
FROM
area
WHERE
FIND_IN_SET(
areaid,
getChildrenOrg (620000)
)
结果:
一、查询上级方法
SELECT *
FROM (
SELECT
@r AS _id,
(SELECT @r := parentid FROM area WHERE areaid = _id) AS parent_id,
@l := @l + 1 AS lvl
FROM
(SELECT @r := 330324, @l := 0) vars,
area h
WHERE @r <> 0) T1
JOIN area T2
ON T1._id = T2.areaid
ORDER BY areaid;
注意其中的330324就是子节点areaid
结果如下: