麻烦看看这个SQL语句哪错了

select 
sum(  case when LS_INV_BACK.sell_price<=0.0 or LS_INV_BACK.sell_price is null or LS_INV_BACK.retail_price<=0 or LS_INV_BACK.retail_price is null then 0.0 sum(  case when LS_INV_BACK.sell_pri