选择列值忽略总和在SQL Server

Question

表JobMaster：

JobID | PLID | SetupTime | 
|1  | 1 |  10  | 
|2  | 2 |  20  | 
|2  | 3 |   | 
|3  | 1 |  05  | 
|3  | 3 |  12  | 

表OpertaionMaster：

|PLID | SetupTime    | 
| 1 | 12     | 
| 2 | 15     | 
| 3 | 20     | 

Outupt包含

表JobMaster

JobID | Productivity | 
|1  |  12  | 
|2  |  15  | 
|3  |  32  | 

需要OperationMaster加入设置时间，如果在JobMaster 的SetupTime不存在，那么它应该忽略另外setupTime值

请帮我提前

感谢

Answer 1

是不是它是一个简单的INNER JOIN和WHERE jm.SetupTime IS NOT NULL？

SELECT jm.JobID, jm.SetupTime AS Productivity 
FROM JobMaster jm 
INNER JOIN OpertaionMaster om 
    ON jm.PLID = om.PLID 
WHERE jm.SetupTime IS NOT NULL 

Answer 2

Join两个表一起，对每个作业ID做GROUP BY和SUM：

select j.jobid, sum(o.SetupTime) 
from JobMaster as j 
    join OpertaionMaster as o on j.PLID = o.PLID 
group by j.jobid 

如果你也想返回作业ID的，没有任何时间，做LEFT JOIN而不是仅仅JOIN。