这个说法：
SELECT @startdate = inserted.startdate, @enddate = inserted.enddate,
@roomnumber = inserted.roomnumber
FROM inserted, bookinginfo
WHERE @roomnumber = bookinginfo.roomnumber AND
(@startdate BETWEEN bookinginfo.startdate AND bookinginfo.enddate) AND
(@enddate BETWEEN bookinginfo.startdate AND bookinginfo.enddate)
是 非常 可疑的。您要在中分配变量，select并在中使用相同的变量where。将其表示为正常内容是否有问题join？
SELECT @startdate = i.startdate, @enddate = i.enddate, @roomnumber = i.roomnumber
FROM inserted i JOIN
bookinginfo bi
ON i.roomnumber = bi.roomnumber AND
(i.startdate BETWEEN bi.startdate AND bi.enddate) AND
(i.enddate BETWEEN bi.startdate AND bi.enddate) AND
i.BookinginfoID <> bi.BookinginfoID;
这仍然不能满足您的需求，原因有两个。首先，这种逻辑是不正确的。第二，if甚至没有使用它。我认为以下是触发器主体的要求：
IF (EXISTS (SELECT 1
FROM inserted i JOIN
bookinginfo bi
ON i.roomnumber = bi.roomnumber AND
i.startdate <= bi.enddate AND
i.enddate >= bi.startdate AND
i.BookinginfoID <> bi.BookinginfoID;
)
BEGIN
RAISERROR ('Double bookings are not allowed',16,1)
. . .
END;
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