IF NOT EXISTS (SELECT * FROM SYSCOLUMNS INNER JOIN SYSOBJECTS ON SYSOBJECTS.id = SYSCOLUMNS.id 
               WHERE SYSCOLUMNS.NAME = 'TEKLIFFIYAT' AND SYSOBJECTS.name = 'MUH_SATINALMAISL')
ALTER TABLE MUH_SATINALMAISL ADD TEKLIFFIYAT FLOAT
GO