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MySql利用父id遞歸向下查詢(xún)子節(jié)點(diǎn)的方法實(shí)例

更新時(shí)間：2022年03月24日 11:44:54 作者：堯上有農(nóng)

項(xiàng)目中遇到一個(gè)需求,要求查處菜單節(jié)點(diǎn)的所有節(jié)點(diǎn),在網(wǎng)上查了一下,大多數(shù)的方法用到了存儲(chǔ)過(guò)程,由于線上環(huán)境不能隨便添加存儲(chǔ)過(guò)程,所以自己寫(xiě)一個(gè),這篇文章主要給大家介紹了關(guān)于MySql利用父id遞歸向下查詢(xún)子節(jié)點(diǎn)的相關(guān)資料,需要的朋友可以參考下

不用寫(xiě)存儲(chǔ)過(guò)程，不用建數(shù)據(jù)庫(kù)函數(shù)，一段sql就可以實(shí)現(xiàn)

SELECT
	ID.LEVEL,
	DATA.* 
FROM
	(
	SELECT
		@ids AS _ids,
		( SELECT @ids := GROUP_CONCAT( region_id ) FROM region WHERE FIND_IN_SET(parent_id, @ids ) ) AS cids,
		@l := @l + 1 AS LEVEL 
	FROM
		region,
		( SELECT @ids := 3, @l := 0 ) b 
	WHERE
		@ids IS NOT NULL 
	) ID,
	region DATA 
WHERE
	FIND_IN_SET( DATA.region_id, ID._ids ) 
ORDER BY
	LEVEL

測(cè)試

--創(chuàng)建測(cè)試環(huán)境
create table t_test(
	id int PRIMARY key,
	parent_id int,
	name varchar(200)
)

insert t_test VALUES(1,null,"中國(guó)");

insert t_test VALUES(2,1,"華北");

insert t_test VALUES(3,2,"山西省");
insert t_test VALUES(4,2,"北京");

insert t_test VALUES(5,3,"臨汾市");
insert t_test VALUES(6,4,"北京市");


insert t_test VALUES(7,5,"堯都區(qū)");
insert t_test VALUES(8,6,"朝陽(yáng)區(qū)");

insert t_test VALUES(9,7,"解放西路");
insert t_test VALUES(10,8,"朝陽(yáng)北路");


SELECT * FROM t_test;

測(cè)試數(shù)據(jù)展示

查詢(xún) id=1，查詢(xún)中國(guó)下邊有哪些地方

SELECT
	ID.LEVEL,
	DATA.* 
FROM
	(
	SELECT
		@ids AS _ids,
		( SELECT @ids := GROUP_CONCAT( id ) FROM t_test WHERE FIND_IN_SET(parent_id, @ids ) ) AS cids,
		@l := @l + 1 AS LEVEL 
	FROM
		t_test,
		( SELECT @ids := 1, @l := 0 ) b 
	WHERE
		@ids IS NOT NULL 
	) ID,
	t_test DATA 
WHERE
	FIND_IN_SET( DATA.id, ID._ids ) 
ORDER BY
	LEVEL

id=3，查詢(xún)山西下邊有哪些地方

SELECT
	ID.LEVEL,
	DATA.* 
FROM
	(
	SELECT
		@ids AS _ids,
		( SELECT @ids := GROUP_CONCAT( id ) FROM t_test WHERE FIND_IN_SET(parent_id, @ids ) ) AS cids,
		@l := @l + 1 AS LEVEL 
	FROM
		t_test,
		( SELECT @ids := 3, @l := 0 ) b 
	WHERE
		@ids IS NOT NULL 
	) ID,
	t_test DATA 
WHERE
	FIND_IN_SET( DATA.id, ID._ids ) 
ORDER BY
	LEVEL

id=4，查詢(xún)北京下邊有哪些地方

最后再?gòu)?id=2 華北地區(qū)往下查詢(xún)

總結(jié)

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