Declare @Id Int                               
Select @Id = Id From sysobjects Where Name = 'Guy'
if not Exists(SELECT id FROM syscolumns WHERE id = @Id  and Name = 'economic_code')
ALTER TABLE Guy ADD  economic_code  varchar(12) Default(0) Null



Select @Id = Id From sysobjects Where Name = 'Guy'
if not Exists(SELECT * FROM syscolumns WHERE id = @Id  and Name = 'CartOnly')
ALTER TABLE Guy ADD  CartOnly  Char(1) Default(0) Null