mysql查询获取与其公司快递相关的每个状态的计数

Question

我有两张桌子

1. company_details ---- company_id, name, address
2. company_courier_status ---- courier_id, company_id, status

状态列将包含0,1,2值

0 --- processing
1 --- success
2 --- returned 

如何编写mysql查询以获取以下输出

company_name  processing  success returned

处理列值是具有0的状态列值的计数 类似的成功和返回列

提前致谢

Answer 1

你可以这样做：

SELECT
  a.name AS company_name,
  SUM(b.status = 0) AS processing,
  SUM(b.status = 1) AS success,
  SUM(b.status = 2) AS returned
FROM company_details a
LEFT JOIN company_courier_status b ON a.company_id = b.company_id
GROUP BY a.company_id, a.name