Consulta entre fechas

[Libras]

Código SQL:

SELECT * FROM(
SELECT B.COD_TRABAJADOR,B.COD_CONCEPASIST,A.ANO,A.MES,A.SEMANA,B.CANTIDAD AS HORAS
FROM RH_PLANILLA_MENSUAL_CABECERA A, RH_REGISTRO_HORAS B  
WHERE A.TIP_PLANILLA='E' AND A.COD_CLASE_PLANILLA='01' AND A.FLG_STATUS_PLANILLA='L' AND
     ((A.ANO>='2013' AND A.MES >='07')) 
AND      
      A.TIP_PLANILLA=B.TIP_PLANILLA AND A.NUM_CORRE_PLANILLA=B.NUM_CORRE_PLANILLA AND B.COD_CONCEPASIST IN ('AS01','HE01','HE02','HE03')
UNION
SELECT B.COD_TRABAJADOR,B.COD_CONCEPASIST,A.ANO,A.MES,A.SEMANA,B.CANTIDAD AS HORAS
FROM RH_PLANILLA_MENSUAL_CABECERA A, RH_REGISTRO_HORAS B  
WHERE A.TIP_PLANILLA='E' AND A.COD_CLASE_PLANILLA='01' AND A.FLG_STATUS_PLANILLA='L' AND
     ((A.ANO>='2014' AND A.MES >='08')) 
AND      
      A.TIP_PLANILLA=B.TIP_PLANILLA AND A.NUM_CORRE_PLANILLA=B.NUM_CORRE_PLANILLA AND B.COD_CONCEPASIST IN ('AS01','HE01','HE02','HE03')
)
AS t1 ORDER BY COD_TRABAJADOR,ANO,MES,SEMANA,COD_CONCEPASIST
 

Prueba con este :)