Use The Reference Column Name In The Same SELECT Querry

Hi,
I am writing the following querry.





Code Snippet

Select dbo.fn_EnGiftId(116) AS 'EnGiftId', dbo.fn_DeGiftId(''+ EnGiftId +'') AS 'DeGiftId'
But the above querry giving me the following error When i am executing the querry:




Code Snippet

Server: Msg 207, Level 16, State 3, Line 1
Invalid column name 'EnGiftId'.
The scenario is I have created two functions 1st is for encryption of GiftId and 2nd is for Decryption of the Encrypted Giftid.
But in the same select querry i want to use the name of column which i have given to the encrypted data in the selct querry i want to use that same column name in the decryption function uin the same querry.

When i am executing the below querry it gives me the required output. So Why not above querry.




Code Snippet

Select dbo.fn_EnGiftId(116) AS 'EnGiftId', dbo.fn_DeGiftId(''+ dbo.fn_EnGiftId(116) +'') AS 'DeGiftId'
i d't want to write the encryption function again and again. Is theer any way to avoid this.?????