IF NOT EXISTS (SELECT * FROM SYSCOLUMNS INNER JOIN SYSOBJECTS ON SYSOBJECTS.id = SYSCOLUMNS.id 
               WHERE SYSCOLUMNS.NAME = 'MDLILACACIKLAMA' AND SYSOBJECTS.name = 'HMALZILAC')
ALTER TABLE dbo.HMALZILAC ADD
	MDLILACACIKLAMA nvarchar(500) NULL
go