SQL从表中减去时间(对于第二个表中的特定时间状态，会额外减少)

Question

我有表T1和T2。

T1

ID    TIME1    TIME2  
1001    1        10
1002    1        20

T2

ID        STATUS    TIME
1001      NEW         1
1001      CLOSED      10
1002      NEW         1
1002      HOLD        5
1002      CLOSED      13

如果表T2中不存在状态HOLD，我想要结果TIME2-TIME1；或者TIME2-TIME1-TIME，如果该记录的表中存在状态HOLD

1001   9 (10-1)
1002   14(20-1-5)

我最初写了SQL查询，但这不起作用，因为它为第一条记录返回NULL，而为第二条记录返回OK

SELECT T1.ID,T1.TIME2-T1.TIME1-T2.TIME
FROM T1
LEFT OUTER JOIN T2 ON T1.ID=T2.ID AND T2.STATUS='HOLD'

感谢

Answer 1

或简称

select 
    t1.id,
    t1.time2-case when status='HOLD' then t2.time else 0 end-t1.time1
from
    t1 left join t2 on t1.id=t2.id and t2.status='HOLD'

Answer 2

SELECT T1.ID
    , Case 
            When T2.STATUS = 'HOLD' THEN T1.Time2 - T1.Time1 - T2.Time 
            Else T1.Time2 -T1.Time1 
      END
FROM T1
LEFT OUTER JOIN T2 ON T1.ID=T2.ID AND T2.STATUS='HOLD'

Answer 3

显然，表T2可能包含多个与T1.ID匹配的行。假设T2总是包含至少一个这样的行，那么我们可以执行：

select T1.ID, min(case when T2.STATUS<>'HOLD' then T1.TIME2-T1.TIME1 
when T2.STATUS='HOLD' then  T1.TIME2-T1.TIME1-T2.[TIME] end)
from T1   join  T2 
on T1.ID=T2.ID
group by T1.ID