let test this
Create Procedure InsData @FirstName varchar(50), @LastName varchar(50)
As
Begin
Declare @id int
Select @id=max(CAST(SUBSTRING(id,2,9) as Int)) from TableName
Insert into TableName(id,firstname,lastname)
Values('L'+CAST((@id+1) as varchar(10)+'BCA',@FirstName,@LastName)
End