if not exists(select 1 from syscolumns where id = object_id('EST_PROD_TBL_COMIS_REGRESSAO') and name = 'TP_REGRESSAO')
begin 
ALTER TABLE dbo.EST_PROD_TBL_COMIS_REGRESSAO ADD
	TP_REGRESSAO int NOT NULL CONSTRAINT DF_EST_PROD_TBL_COMIS_REGRESSAO_TP_REGRESSAO DEFAULT 0
end