ALTER TABLE HesabIran1.dbo.kala ALTER COLUMN Name NVARCHAR (1000) null ; ALTER TABLE HesabIran1.dbo.kala ALTER COLUMN EnglishName NVARCHAR (1000) null ; IF not EXISTS( SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'kala' AND COLUMN_NAME = 'Convert_ID') begin ALTER TABLE kala Add Convert_ID int null end