IF NOT EXISTS(SELECT 1 FROM syscolumns WHERE ID = OBJECT_ID('EST_TRIB') AND NAME = 'TRIB_FC_SPED')
begin  
	ALTER TABLE dbo.EST_TRIB ADD
	TRIB_FC_SPED varchar(6) NOT NULL CONSTRAINT DF_EST_TRIB_TRIB_FC_SPED DEFAULT ''
end