Reading through this helps solve a similar problem. The data is in decimal datatype - [DOB] [decimal](8, 0) NOT NULL - eg - 19700109. I want to get at the month. The solution is to combine SUBSTRING with CONVERT to VARCHAR.
SELECT [NUM]
,SUBSTRING(CONVERT(VARCHAR, DOB),5,2) AS mob
FROM [Dbname].[dbo].[Tablename]