如何计算一天内的总记录时间？

Question

如何计算在SQL中花费的总小时数？例如，对于此员工，在此期间花费的总小时数为12-2=10。

EmpID   Enter/Exit  Time 
 2999   Entry   06:00AM 
 2999   Exit    12:00PM
 2999   Entry   01:00PM 
 2999   Exit    03:00PM 
 2999   Entry   04:00PM
 2999   Exit    06:00PM

Answer 1

在SQL Server2008中，这是痛苦的。假设进入/退出值已连接，并且时间实际上是有效的日期时间，则可以执行以下操作：

select empid,
       sum(datediff(hour, t.time, t2.time)) as sum_hours
from t cross apply
     (select top (1) t2.*
      from t t2
      where t2.empid = t.empid and
            t2.enter_exit = 'exit' and
            t2.time > t.time
     ) as next_time
where t.enter_exit = 'enter'
group by empid;