如何从 SQL 计数中排除特定行

Question

我需要从 SQL 服务器的COUNT中排除某行。 这就是我所拥有的：

SELECT COUNT(GuestId)TotalBooked
FROM GuestStayDetails
WHERE (@ArrivalDate = ArrivalDate)
   OR (@DepartureDate = DepartureDate) 
   OR (@ArrivalDate < ArrivalDate AND @DepartureDate = DepartureDate) 
   OR (@ArrivalDate = ArrivalDate AND @DepartureDate < DepartureDate)
   OR (@ArrivalDate < ArrivalDate AND @DepartureDate > DepartureDate)
   OR (@ArrivalDate < DepartureDate AND @DepartureDate > DepartureDate)
   OR (@ArrivalDate BETWEEN ArrivalDate AND DATEADD(Day, -1, DepartureDate))
   OR (@DepartureDate BETWEEN DATEADD(Day, -1, ArrivalDate) AND DepartureDate)
  AND Student = 1
  AND Cancelled = 0
  AND GuestStayDetails.GuestId != @GuestId;

如果我删除最后一个AND GuestStayDetails.GuestId;= @GuestId; 它给了我预期的COUNT但是我必须排除其中一个GuestID 。 有什么建议么？

Answer 1

看起来您需要在 -OR- 条件周围添加一些括号。 你能测试一下并告诉我们它是否有效吗？ 请注意 -OR- 子句周围的左括号和右括号。

SELECT COUNT(GuestId)TotalBooked
FROM GuestStayDetails
WHERE (
        (@ArrivalDate = ArrivalDate)
     OR (@DepartureDate = DepartureDate) 
     OR (@ArrivalDate < ArrivalDate AND @DepartureDate = DepartureDate) 
     OR (@ArrivalDate = ArrivalDate AND @DepartureDate < DepartureDate)
     OR (@ArrivalDate < ArrivalDate AND @DepartureDate > DepartureDate)
     OR (@ArrivalDate < DepartureDate AND @DepartureDate > DepartureDate)
     OR (@ArrivalDate BETWEEN ArrivalDate AND DATEADD(Day, -1, DepartureDate))
     OR (@DepartureDate BETWEEN DATEADD(Day, -1, ArrivalDate)AND DepartureDate) 
  )
  AND Student = 1
  AND Cancelled = 0
  AND GuestStayDetails.GuestId != @GuestId; 

Answer 2

看起来您正在寻找重叠的时间间隔 - 以及您的括号问题。 如果是这种情况，您可以显着简化查询：

WHERE @ArrivalDate <= DepartureDate AND
      @DepartureDate >= ArrivalDate AND
      Student = 1 AND
      Cancelled = 0 AND
      GuestStayDetails.GuestId <> @GuestId

这完全消除了对任何括号的需要。