IF NOT EXISTS (SELECT * FROM SYSCOLUMNS INNER JOIN SYSOBJECTS ON SYSOBJECTS.id = SYSCOLUMNS.id 
              WHERE SYSCOLUMNS.NAME = 'KODTURU' AND SYSOBJECTS.name = 'OZELSIGORTACARI')
ALTER TABLE dbo.[OZELSIGORTACARI] ADD KODTURU NVARCHAR(20) NULL
go