How to set a check on SQL Server?

Hi,

I need to add table called group with a column called code

How do I add a check constraint to the column so it will only allow the following alphabetic characters (D, M, O, P or T) followed by 2 numeric characters.

From stackoverflow

• simple check constraint is all you need

  create table blatest(code char(3))
  
  alter table blatest add  constraint ck_bla 
  check (code like '[DMOPT][0-9][0-9]' )
  GO
  

  test

  insert blatest values('a12') --fails
  insert blatest values('M12')  --good
  insert blatest values('D12') --good
  insert blatest values('DA1') --fails
  

  If you need it to be case sensitive then you have to create the constraint like this

  alter table blatest add  constraint ck_bla 
  check (code like '[DMOPT][0-9][0-9]' COLLATE SQL_Latin1_General_CP1_CS_AS )
  GO
  

  D12 will succeed but d12 will not in that case