CREATE TABLE [dbo].[tbl_Log_ReferralLog](
[ID] [int] IDENTITY(1,1) NOT NULL
, [TimeLogged] [datetime] NULL default(getdate())
,[Specialty] varchar NULL
, [MRNumber] char NULL)
Insert into [dbo].tbl_Log_ReferralLog values
('cardiology','1234500000')
,('cardiology','1234500000')
,('cardiology','1234500000')
,('cardiology','1234500001')
,('cardiology','1234500002')
Select *
,dense_rank() Over(Partition by [Specialty] Order by [MRNumber]) dnk
from [dbo].[tbl_Log_ReferralLog]
drop table [dbo].[tbl_Log_ReferralLog]