SQL 你如何测试东西是否超过 3 个月？
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How do you test if something is older than 3 months?
提问by Eon
I have been having some trouble to select the rows of my table which has a date of 3 months prior of today. I tried using DATE(NOW() - INTERVAL 3 MONTH)in my where clause, but no luck. How do I check in SQL Server if a item is older than 3 months?
我在选择日期为今天之前 3 个月的表中的行时遇到了一些麻烦。我尝试DATE(NOW() - INTERVAL 3 MONTH)在我的 where 子句中使用，但没有运气。如果项目超过 3 个月，我如何在 SQL Server 中进行检查？
UPDATE[TCTdb].[dbo].[Stock]
SET[Warehouse] = 'old'
WHERE [ManufacturedDate] <= DATE(NOW() - INTERVAL 3 MONTH)
回答by Code Magician
Your syntax appears to be wrong.
您的语法似乎是错误的。
That should be
那应该是
UPDATE[TCTdb].[dbo].[Stock]
SET[Warehouse] = 'old'
WHERE [ManufacturedDate] <= DATEADD(mm, -3, GETDATE())
回答by canon
Use dateadd().
使用dateadd().
update [TCTdb].[dbo].[Stock]
set [WareHouse] = 'old'
where [ManufacturedDate] < dateadd(month,-3,getdate())
I suggest dateadd()over datediff()because I think you're going to get unexpected results using datediff()with the monthdatepart.
我建议dateadd()过datediff()，因为我觉得你会得到意想不到的使用效果datediff()与month日期部分。
Consider that the following statements both return 3:
考虑以下语句都返回3：
select datediff(month, '1/1/2011','4/1/2011')
select datediff(month, '1/1/2011','4/30/2011')
Either works in this particular case... Just keep that behavior in mind.
要么在这种特殊情况下工作......请记住这种行为。
回答by hspain
The DATEDIFF function should be helpful to you:
DATEDIFF 函数应该对您有所帮助：
http://msdn.microsoft.com/en-us/library/ms189794.aspx
http://msdn.microsoft.com/en-us/library/ms189794.aspx
UPDATE[TCTdb].[dbo].[Stock]
SET[Warehouse] = 'old'
WHERE DATEDIFF(month, [ManufacturedDate], GETDATE()) > 3
回答by JohnD
try out DATEDIFF:
试试 DATEDIFF：
SELECT
case
when DATEDIFF(month, '2005-12-31' , '2006-04-01 ') > 3
then 'yes'
else 'no'
end
Hope that helps,
希望有所帮助，
John
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