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How to implement recursive query in mysql

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Dec 10, 2020 pm 03:28 PM

mysqlrecursive query

Mysql method to implement recursive query: first create a table and initialize the data; then recurse downward and use the [find_in_set()] function and [group_concat()] function to implement the recursive query.

How to implement recursive query in mysql

The operating environment of this tutorial: windows7 system, mysql8.0.22 version, thinkpad t480 computer.

Free learning recommendation: mysql tutorial(Video)

mysql implementation Recursive query method:

1. Create table

DROP TABLE IF EXISTS `t_areainfo`;
CREATE TABLE `t_areainfo` (
 `id` int(11) NOT &#39;0&#39; AUTO_INCREMENT,
 `level` int(11) DEFAULT &#39;0&#39;,
 `name` varchar(255) DEFAULT &#39;0&#39;,
 `parentId` int(11) DEFAULT &#39;0&#39;,
 `status` int(11) DEFAULT &#39;0&#39;,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=65 DEFAULT CHARSET=utf8;

2. Initial data

INSERT INTO `t_areainfo` VALUES (&#39;1&#39;, &#39;0&#39;, &#39;中国&#39;, &#39;0&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;2&#39;, &#39;0&#39;, &#39;华北区&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;3&#39;, &#39;0&#39;, &#39;华南区&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;4&#39;, &#39;0&#39;, &#39;北京&#39;, &#39;2&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;5&#39;, &#39;0&#39;, &#39;海淀区&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;6&#39;, &#39;0&#39;, &#39;丰台区&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;7&#39;, &#39;0&#39;, &#39;朝阳区&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;8&#39;, &#39;0&#39;, &#39;北京XX区1&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;9&#39;, &#39;0&#39;, &#39;北京XX区2&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;10&#39;, &#39;0&#39;, &#39;北京XX区3&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;11&#39;, &#39;0&#39;, &#39;北京XX区4&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;12&#39;, &#39;0&#39;, &#39;北京XX区5&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;13&#39;, &#39;0&#39;, &#39;北京XX区6&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;14&#39;, &#39;0&#39;, &#39;北京XX区7&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;15&#39;, &#39;0&#39;, &#39;北京XX区8&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;16&#39;, &#39;0&#39;, &#39;北京XX区9&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;17&#39;, &#39;0&#39;, &#39;北京XX区10&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;18&#39;, &#39;0&#39;, &#39;北京XX区11&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;19&#39;, &#39;0&#39;, &#39;北京XX区12&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;20&#39;, &#39;0&#39;, &#39;北京XX区13&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;21&#39;, &#39;0&#39;, &#39;北京XX区14&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;22&#39;, &#39;0&#39;, &#39;北京XX区15&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;23&#39;, &#39;0&#39;, &#39;北京XX区16&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;24&#39;, &#39;0&#39;, &#39;北京XX区17&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;25&#39;, &#39;0&#39;, &#39;北京XX区18&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;26&#39;, &#39;0&#39;, &#39;北京XX区19&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;27&#39;, &#39;0&#39;, &#39;北京XX区1&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;28&#39;, &#39;0&#39;, &#39;北京XX区2&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;29&#39;, &#39;0&#39;, &#39;北京XX区3&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;30&#39;, &#39;0&#39;, &#39;北京XX区4&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;31&#39;, &#39;0&#39;, &#39;北京XX区5&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;32&#39;, &#39;0&#39;, &#39;北京XX区6&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;33&#39;, &#39;0&#39;, &#39;北京XX区7&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;34&#39;, &#39;0&#39;, &#39;北京XX区8&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;35&#39;, &#39;0&#39;, &#39;北京XX区9&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;36&#39;, &#39;0&#39;, &#39;北京XX区10&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;37&#39;, &#39;0&#39;, &#39;北京XX区11&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;38&#39;, &#39;0&#39;, &#39;北京XX区12&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;39&#39;, &#39;0&#39;, &#39;北京XX区13&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;40&#39;, &#39;0&#39;, &#39;北京XX区14&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;41&#39;, &#39;0&#39;, &#39;北京XX区15&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;42&#39;, &#39;0&#39;, &#39;北京XX区16&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;43&#39;, &#39;0&#39;, &#39;北京XX区17&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;44&#39;, &#39;0&#39;, &#39;北京XX区18&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;45&#39;, &#39;0&#39;, &#39;北京XX区19&#39;, &#39;4&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;46&#39;, &#39;0&#39;, &#39;xx省1&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;47&#39;, &#39;0&#39;, &#39;xx省2&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;48&#39;, &#39;0&#39;, &#39;xx省3&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;49&#39;, &#39;0&#39;, &#39;xx省4&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;50&#39;, &#39;0&#39;, &#39;xx省5&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;51&#39;, &#39;0&#39;, &#39;xx省6&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;52&#39;, &#39;0&#39;, &#39;xx省7&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;53&#39;, &#39;0&#39;, &#39;xx省8&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;54&#39;, &#39;0&#39;, &#39;xx省9&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;55&#39;, &#39;0&#39;, &#39;xx省10&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;56&#39;, &#39;0&#39;, &#39;xx省11&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;57&#39;, &#39;0&#39;, &#39;xx省12&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;58&#39;, &#39;0&#39;, &#39;xx省13&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;59&#39;, &#39;0&#39;, &#39;xx省14&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;60&#39;, &#39;0&#39;, &#39;xx省15&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;61&#39;, &#39;0&#39;, &#39;xx省16&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;62&#39;, &#39;0&#39;, &#39;xx省17&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;63&#39;, &#39;0&#39;, &#39;xx省18&#39;, &#39;1&#39;, &#39;0&#39;);
INSERT INTO `t_areainfo` VALUES (&#39;64&#39;, &#39;0&#39;, &#39;xx省19&#39;, &#39;1&#39;, &#39;0&#39;);

3. Downward recursion

Use the find_in_set() function and the group_concat() function to implement recursive query:

How to implement recursive query in mysql

DROP FUNCTION IF EXISTS queryChildrenAreaInfo;
DELIMITER ;;
CREATE FUNCTION queryChildrenAreaInfo(areaId INT)
RETURNS VARCHAR(4000)
BEGIN
DECLARE sTemp VARCHAR(4000);
DECLARE sTempChd VARCHAR(4000);
SET sTemp=&#39;$&#39;;
SET sTempChd = CAST(areaId AS CHAR);
WHILE sTempChd IS NOT NULL DO
SET sTemp= CONCAT(sTemp,&#39;,&#39;,sTempChd);
SELECT GROUP_CONCAT(id) INTO sTempChd FROM t_areainfo WHERE FIND_IN_SET(parentId,sTempChd)>0;
END WHILE;
RETURN sTemp;
END
;;
DELIMITER ;

4. Calling method

SELECT queryChildrenAreaInfo(1);

How to implement recursive query in mysql

Query all nodes under the ID "4"

SELECT * FROM t_areainfo WHERE FIND_IN_SET(id,queryChildrenAreaInfo(4));

5. Upward recursion

DROP FUNCTION IF EXISTS queryChildrenAreaInfo1;
DELIMITER;;
CREATE FUNCTION queryChildrenAreaInfo1(areaId INT)
RETURNS VARCHAR(4000)
BEGIN
DECLARE sTemp VARCHAR(4000);
DECLARE sTempChd VARCHAR(4000);
SET sTemp=&#39;$&#39;;
SET sTempChd = CAST(areaId AS CHAR);
SET sTemp = CONCAT(sTemp,&#39;,&#39;,sTempChd);
SELECT parentId INTO sTempChd FROM t_areainfo WHERE id = sTempChd;
WHILE sTempChd <> 0 DO
SET sTemp = CONCAT(sTemp,&#39;,&#39;,sTempChd);
SELECT parentId INTO sTempChd FROM t_areainfo WHERE id = sTempChd;
END WHILE;
RETURN sTemp;
END
;;
DELIMITER ;

6. Calling method

Query all superior nodes of the node with id "7":

SELECT * from t_areainfo where FIND_IN_SET(id,queryChildrenAreaInfo1(7));

How to implement recursive query in mysql

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