任何人都可以糾正sql查詢嗎？

Question

我需要城市和空缺的數量，在這個城市的工作。城市，簡歷，空缺 - 表。

下面是一個查詢我寫的，但它不工作（第二LEFT JOIN不工作）

SELECT c.name city_name, 
COUNT(v.id) vac_num, (r.id) res_num 
FROM mnk_city c 
LEFT JOIN mnk_vacancy 
ON v.cityId = c.id 
LEFT JOIN mnk_resume 
ON c.id = r.cityId 
GROUP BY c.name 

Answer 1

SELECT c.name city_name, 
COUNT(v.id) vac_num, (r.id) res_num 
FROM mnk_city c 
LEFT JOIN mnk_vacancy v 
ON v.cityId = c.id 
LEFT JOIN mnk_resume r 
ON c.id = r.cityId 
GROUP BY c.name 

你缺少了表的別名。

Answer 2

看來你錯過了一些表別名 - mnk_vacancy應該跟着v，據我所知，mnk_resume應該跟着r。

SELECT c.name city_name, 
COUNT(v.id) vac_num, (r.id) res_num 
FROM mnk_city c 
LEFT JOIN mnk_vacancy v 
ON v.cityId = c.id 
LEFT JOIN mnk_resume r 
ON c.id = r.cityId 
GROUP BY c.name