mysql 联合2个列的数据 然后呈现出来

SELECT a.voyageNum,CONCAT(a.startDate,'~',a.endDate) AS 日期  FROM tchw_voyageoilcost a ,tchw_voyageoilcostinfo b   WHERE a.isDeleted=0 AND   a.id=b.voyageOilCostId AND a.shipId=3 AND a.belongMonth='2013-09' ORDER BY a.voyageNum