DECLARE @Id Int                               
SELECT @Id = Id From sysobjects Where Name = 'Shops'
IF not Exists(SELECT * FROM syscolumns WHERE id = @Id and Name = 'Address')
  Alter Table Shops Add Address NVARCHAR(MAX) NULL 

SELECT @Id = Id From sysobjects Where Name = 'Shops'
IF not Exists(SELECT * FROM syscolumns WHERE id = @Id and Name = 'Phone')
  Alter Table Shops Add Phone VARCHAR(30) NULL 