顯示最新的ID和公司ID

Question

表：服務

id companyid jobid 
1   1  1 
2   1  2 
3   1  2 
4   2  3 
5   3  4 
6   3  1 
7   4  2 
8   5  2 

我鍵入下面的查詢：

SELECT * 
FROM service 
WHERE jobID = 2 
ORDER BY companyID desc, ID desc 

我也得到了以下的輸出：

id companyid jobid 
8   5  2 
7   4  2 
3   1  2 
2   1  2 

但我希望我的預期產出如下：

id companyid jobid 
8   5  2 
7   4  2 
3   1  2 

如何修改查詢以獲得預期的輸出？

Answer 1

你應該能夠只是應用max功能與group by條款沿：

select max(id) id, companyid, jobid 
from service 
where jobid = 2 
group by companyid, jobid 
order by id desc 

鑑於您的樣本數據的結果將是：

id companyid jobid 
8 5   2 
7 4   2 
3 1   2 

Answer 2

這應該工作：

select * from service s1 
join (select max(id) as id 
     from service 
     group by jobid, companyid) s2 on s1.id = s2.id 
where s1.jobid = 2--can comment to select all latest jobs