sql自关联查询上级id对应的名字

s

1，表结构：city_info

 2，实体类

 3，sql：

　　方法一：关联查询

　　select ci1.id,(select ci2.name from city_info ci2 where ci2.id = ci1.pId) as pName,ci1.name,ci1.title,ci1.type from city_info ci1;

　　方法二：左外连接查询

　　select ci1.id,ci2.name pName,ci1.name,ci1.title,ci1.type from city_info ci1 LEFT JOIN city_info ci2 ON ci1.pId = ci2.id;

4,查询结果

sql自关联查询上级id对应的名字

原文：https://www.cnblogs.com/zuok9527/p/12028138.html