How to auto increment an alphanumeric Primary Key in SQL Server Database

DECLARE @Table TABLE (Id VARCHAR(10))

INSERT INTO @Table
SELECT 'abc001'
UNION ALL
SELECT 'abc002'

--To generate new Id
DECLARE @AlphaId VARCHAR(10)
DECLARE @Count INT

SELECT @Count = COUNT(*) + 1 FROM @Table

SET   @AlphaID = 'abc' + LEFT('00' + CAST(@Count AS VARCHAR(10)), 3)
SELECT @AlphaID