MySQL的：集團通過與伯爵多個字段

Question

如果我有一個單一的領域，比方說，PROJECT_ID在這裏我要計數的出現，我會做這樣的事情：

select project_id, count(project_id) as count from tbl group by project_id, order by count desc 

，如果我要算髮生什麼兩個字段在同一個表中的組合，即計算project_id和service_id的組合唯一的行數？

所以，所以我有記錄在我的表像：

project_id service_id 
1   1 
1   2 
1   2 
1   2 
1   2 
1   3 
1   4 
1   4 
1   4 


I would want the result of my query to be something like: 

project_id service_id count 
1   1   1 
1   2   4 
1   3   1 
1   4   3 

Answer 1

select project_id, service_id, count(*) as count 
from tbl group by project_id, service_id 
order by count(*) desc 

只需添加service_id您group by和select列表。這應該做到這一點。

編輯 -

按照評論從@Rajah似乎對你的期望的輸出，你需要使用

order by project_id asc, service_id asc