IF NOT EXISTS (SELECT * FROM SYSCOLUMNS INNER JOIN SYSOBJECTS ON SYSOBJECTS.id = SYSCOLUMNS.id 
               WHERE SYSCOLUMNS.NAME = 'UYARIREFVAR' AND SYSOBJECTS.name = 'HTETKIKDETAY')
ALTER TABLE dbo.HTETKIKDETAY ADD
	[UYARIREFVAR] bit NULL
GO