sql server2008里边，全代码太长，我简要说说……
DATEDIFF(MINUTE,alarm_time,end_time)/60 现在这个的结果是各种值
但只要在前面加上 XX - ，这个值就变成了2……
比如 700-DATEDIFF(MINUTE,alarm_time,end_time)/60 结果是698。
求真相
------解决方案--------------------
DECLARE @BeginTime DATETIME
DECLARE @EndTime DATETIME
DECLARE @TotalTime DECIMAL(18, 2)
DECLARE @alarm_time DATETIME --代表表中alarm_time字段
DECLARE @end_time DATETIME --代表表中end_time字段
SET @BeginTime = '2014/7/1 0:00:00'
SET @EndTime = '2014/07/31 23:59:59'
SET @end_time = '2014/7/29 0:00:00'
SET @alarm_time = '2014/6/30 1:00:00'
SELECT @TotalTime = CONVERT(DECIMAL(18, 2), ROUND(CONVERT(DECIMAL(18, 2), DATEDIFF(MINUTE,
@BeginTime,
@EndTime)) / 60,
2))
PRINT @TotalTime
SELECT @totaltime AS a ,
ROUND(CONVERT(DECIMAL(18, 2), DATEDIFF(MINUTE, @BeginTime, @end_time))
/ 60, 2) AS b ,
CONVERT(DECIMAL(18, 2), DATEDIFF(MINUTE, @BeginTime, @end_time)) / 60 AS c ,
DATEDIFF(MINUTE, @BeginTime, @end_time) AS d ,
CONVERT(DECIMAL(18, 2), ROUND(CONVERT(DECIMAL(18, 2), DATEDIFF(MINUTE,
@BeginTime,
@end_time)) / 60,
2)) AS e
SELECT CASE WHEN @alarm_time < @BeginTime
AND @end_time < @EndTime
THEN @totaltime
- CONVERT(DECIMAL(18, 2), ROUND(CONVERT(DECIMAL(18, 2), DATEDIFF(MINUTE,
@BeginTime,
@end_time)) / 60,
2))
WHEN @end_time > @EndTime
AND @alarm_time > @BeginTime
THEN @totaltime