[英]IF ELSE return wrong value in SQL Server
I have a script that need to return the DATETIME from IF ELSE condition.我有一个脚本需要从 IF ELSE 条件返回 DATETIME。 But my return value from this got a wrong value here.但是我的返回值在这里得到了错误的值。
So this is my script所以这是我的脚本
DECLARE @last_date SMALLDATETIME;
DECLARE @end_date SMALLDATETIME;
DECLARE @initial_date SMALLDATETIME;
DECLARE @begin_date SMALLDATETIME;
DECLARE @datediff int;
DECLARE @date_day int;
SET @last_date = NULL;
SET @datediff = NULL;
SET @initial_date = NULL;
IF (@datediff = '' or @datediff is NULL)
SET @datediff = 5;
ELSE
SET @datediff = @datediff;
IF (@last_date = '' or @last_date is NULL)
SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-1, -1);
ELSE
SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, -1, @last_date)-1, -1);
IF (@initial_date = '' or @initial_date is NULL)
SET @begin_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @end_date)-@datediff, 0);
ELSE
SET @begin_date = @initial_date;
SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @begin_date)+@datediff, DATEPART(d,@initial_date));
print(@begin_date)
print(@end_date)
From this logic, it should take a value like this从这个逻辑来看,它应该采用这样的值
but it only return value但它只返回值
But from that script why it entered to ELSE condition @initial_date
?但是从那个脚本为什么它进入 ELSE 条件@initial_date
? is there any something wrong from my script?我的脚本有什么问题吗?
If I understand your issue correctly, the reason for this unexpected result is that the last line ( SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @begin_date) + @datediff, DATEPART(d, @initial_date));
) is outside the IF.. ELSE
block and always sets the value of @end_date
to NULL
.如果我正确理解你的问题,这个意外结果的原因是最后一行( SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @begin_date) + @datediff, DATEPART(d, @initial_date));
)位于IF.. ELSE
块之外,并且始终将NULL
@end_date
Probably an appropriate BEIGN.. END
block in the last IF..ELSE
statement will solve this issue:最后一个IF..ELSE
语句中的适当BEIGN.. END
块可能会解决此问题:
...
IF (@initial_date = '' or @initial_date is NULL)
SET @begin_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @end_date)-@datediff, 0);
ELSE BEGIN
SET @begin_date = @initial_date;
SET @end_date = DATEADD(MONTH, DATEDIFF(MONTH, 0, @begin_date)+@datediff, DATEPART(d,@initial_date));
END
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