MySql 查询从左表获取所有行，从右表获取公共行

Question

表 1 - customer_kitchen_service_plans和数据https://prnt.sc/00_ip7uWiQuq

表 2 - kitchen_service_plans_linking和数据https://prnt.sc/e_GW64THTCFK

以上两个是表，我想以这样的方式加入，它应该返回表 1 中的所有行和表 2 中的常见行

使用表 1 中的kitchen_service_plan_id列和表 2 中的kitchen_service_plan_parent_id列加入

当前查询如下

select * from `customer_kitchen_service_plans` as `cksp` 
left join `kitchen_service_plans_linking` as `kspl` on 
  `kspl`.`kitchen_service_plan_parent_id` = 
  `cksp`.`kitchen_service_plan_id` 
where `cksp`.`status` = 'ACTIVE' and `cksp`.`customer_id` = 2

Answer 1

看看有没有帮助

SELECT * FROM customer_kitchen_service_plans 
LEFT JOIN kitchen_service_plans_linking ON 
          customer_kitchen_service_plans.kitchen_service_plan_id= 
          kitchen_service_plans_linking.kitchen_service_plan_parent_id;

Answer 2

您需要一个左外连接，它返回第一个表中的所有行并从右侧返回匹配行。

select * from `customer_kitchen_service_plans` as cksp 
left outer join `kitchen_service_plans_linking` as kspl on 
  kspl.`kitchen_service_plan_parent_id` = 
  cksp.`kitchen_service_plan_id` 
where cksp.`status` = 'ACTIVE' and cksp.`customer_id` = 2

这是关于MySQL 中的左外连接的讨论