SELECT
 A.GEAR_MODEL || CASE WHEN C.GEAR_SIZE IS NULL OR C.GEAR_SIZE = '' THEN ''
 ELSE ' (' || GEAR_SIZE || ')' END "GEAR_MODEL (GEAR_SIZE)"
 FROM BCDATARSLTS A, BCDISCRETEHEDRS B, MV_BCGEARS C
 WHERE A.DISCRETE_SEQ = B.DISCRETE_SEQ AND B.GEAR_SEQ = C.GEAR_SEQ;