mysql:递归查询
2022/9/18 2:16:25
本文主要是介绍mysql:递归查询,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
原始数据:id,parent_id:父id。
SET NAMES utf8mb4; DROP TABLE IF EXISTS `t_city`; CREATE TABLE `t_city` ( `id` int(0) NOT NULL, `parent_id` int(0) NULL DEFAULT NULL, `name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL, PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic; INSERT INTO `t_city` VALUES (1, 0, 'a'); INSERT INTO `t_city` VALUES (2, 0, 'b'); INSERT INTO `t_city` VALUES (3, 0, 'c'); INSERT INTO `t_city` VALUES (4, 1, 'a1'); INSERT INTO `t_city` VALUES (5, 1, 'a2'); INSERT INTO `t_city` VALUES (6, 2, 'a21'); INSERT INTO `t_city` VALUES (7, 3, 'c1'); INSERT INTO `t_city` VALUES (8, 7, 'c11'); INSERT INTO `t_city` VALUES (9, 7, 'c12'); INSERT INTO `t_city` VALUES (10, 8, 'c11-1'); INSERT INTO `t_city` VALUES (11, 9, 'c12-1');
说明:
*、parent_id为0,表示为根目录。
WITH RECURSIVE cte_city AS( SELECT * FROM t_city WHERE NAME = 'c' UNION ALL SELECT u.* FROM t_city u, cte_city t WHERE u.parent_id = t.id ) SELECT * FROM cte_city;
*、查询c部门下面的所有子部分。
WITH RECURSIVE cte_city AS( SELECT * FROM t_city WHERE NAME = 'c12' UNION ALL SELECT u.* FROM t_city u, cte_city t WHERE u.id = t.parent_id ) SELECT * FROM cte_city;
*、查询:名称为c12的部门及上级部门。
*、多级目录查询(查询出所有“3”号分类下的所有子分类,并且分类名称带上上级分类的名称):
with recursive type_cte as ( select id,name,parent_id from t_city where id = 3 union all select t.id,concat(type_cte2.name,'>',t.name),t.parent_id from t_city t inner join type_cte type_cte2 on t.parent_id = type_cte2.id ) select id, name, parent_id from type_cte;
*、 查询分类的所有父级分类
with recursive type_cte as ( select id,name,parent_id from t_city where id = 8 union all select t.id,concat(type_cte2.name,'>',t.name),t.parent_id from t_city t inner join type_cte type_cte2 on t.id = type_cte2.parent_id ) select id, name, parent_id from type_cte;
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