Generate a unique number in Sql Server 2005

We often find ourselves in the need of generating unique numbers in our database applications.

Let us quickly take a tour of how to do that using Sql server 2005.

SQL
Server contains the NEWID() function. This function creates a unique
value of type uniqueidentifier. We can use this function in several
ways to generate unique numbers to suit our requirements :

Generate GUID's :

UniqueIndentifiers are also knows as GUID's. To generate a GUID use :

SELECT NEWID() as GuidNo

generates FBF2D8E9-F8BE-4F0B-9D49-7CA7C2E3F22C on my machine

Generate only digits :

SELECT ABS(CAST(CAST(NEWID() AS VARBINARY(5)) AS Bigint)) as UniqueNo

generates 427357674589 on my machine

Generate fixed digit unique numbers :

At times, we may also need to generate fixed digit numbers. You can do that in the following manner :

SELECT REPLACE(STR(CAST(CAST(NEWID() AS binary(5)) AS bigint),12),0,0)

generates 470370453006 on my machine