Tsql 出发日期大于到达日期

如何确保我的出发日期大于以下代码中的到达日期

SELECT ArrivalDate, DATEADD(day, RAND(checksum(NEWID()))*1.5
* LengthOfStay.LengthofStay, ArrivalDate) AS DepartureDate    
FROM Bookings, LengthOfStay
ORDER BY ArrivalDate

谢谢

Wayne

尝试此查询

SELECT * FROM
    (
      SELECT 
          ArrivalDate, 
          DATEADD(day, RAND(checksum(NEWID()))*1.5   * LengthOfStay.LengthofStay, ArrivalDate) AS DepartureDate    
      FROM   
          Bookings, LengthOfStay
    ) a
WHERE a.DepartureDate > a.ArrivalDate
ORDER BY a.ArrivalDate

取一个整数。。。从随机化中返回的任何十进制值都将被截断。因此，您可能只是将

0

添加到

ArrivalDate

，导致两个日期相等

您只需在随机化中添加最少的

1

即可解决此问题：

SELECT ArrivalDate, DATEADD(day, 1 + RAND(checksum(NEWID()))*1.5
* LengthOfStay.LengthofStay, ArrivalDate) AS DepartureDate    
FROM Bookings, LengthOfStay
ORDER BY ArrivalDate

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你们知道为什么上面的查询不会插入到一个表中，其中出发日期是一个日期字段吗？