Convert from UniqueIdentifier to BigInt and Back?

Question

declare @uu uniqueidentifier =  \'C50B0567-F8CC-4219-A1E1-91C97BD9AE1B\'
select @uu
declare @zaza bigint = ( select convert(bigint, convert (varbinary(8), @uu, 1)) )         


        

Answer 1

There is no problem with your second convert. When I run your SQL statement in SQL management studio, I get:

------------------------------------
C50B0567-F8CC-4219-A1E1-91C97BD9AE1B

(1 row(s) affected)


--------------------
7423352504965404994

(1 row(s) affected)


------------------------------------
C50B0567-F8CC-4219-0000-000000000000

(1 row(s) affected)

Since you are converting 8 byte value to 16-byte guid, half of guid will be zeroes, which is exactly what you are seeing.