SQL Server DatetimeタイプがNULLの場合、ISNULL(datetime,'')では判断できません.1900-01-01になります.

select top 10 
--(case when zb.Order_CreatedOn is null then '' when zb.Order_CreatedOn<>'1900-01-01' then zb.Order_CreatedOn end)  as Order_CreatedOn,*--datetime      ''，    '',       1900-01-01,''            1900-01-01，     SQL    ，      DBNUll.value     
--isnull(zb.Order_CreatedOn,''),*
zb.Order_CreatedOn,*
from dbo.GKOrder ck
left join dbo.ZBOrder zb on ck.OrderID=zb.Order_TransactionID

 
転載先:https://www.cnblogs.com/BOSET/p/9209334.html