1. select 1 id, '无计划' demandName,'无计划' dsc,'无计划' planName
    2. union all
    3. select A.id,A.demandName,A.dsc,C.planName from demand A,TPRG_PlanAndDemand B,TPRG_Plan C
    4. where A.id = B.DemandId and B.PlanId = C.id