Updating by concatenating columns in PostgreSQL
UPDATE table_nameSET hotelcode = hotelcode || '_' || vendorcitycodeWHERE (vendorid, vendorcitycode) = ('INV27', 'LON')
UPDATE table_nameSET hotelcode = hotelcode || '_' || vendorcitycodeWHERE (vendorid, vendorcitycode) = ('INV27', 'LON')