SQL查詢變量

Question

我需要一個SQL查詢，我需要

SELECT MachineID from TABLE1 

幫助，然後

Count(Passfail) from TABLE2 WHERE MachineID= *MACHINEID 

from the SELECT聲明之前到一個表

Answer 1

你幾乎寫在那裏。你需要閱讀了一下就連接和SQL group by：

select T1.MachineId, count(T2.Passfail) from 
Table1 T1 inner join Table2 T2 on T1.MachineId = T2.Machine Id 
group by T1.MachineId 

編輯： 對於依賴於通過失敗的值單獨計數，我會使用：

select T1.MachineId, 
sum(case when T2.PassFail='pass' then 1 else 0 end) as 'pass', 
sum(case when T2.PassFail='fail' then 1 else 0 end) as 'fail' 
from Table1 T1 inner join 
Table2 T2 on T1.MachineId = T2.machineId 
group by T1.machineId