b."promotionid1"||'-'||b."promotionless1"||','||b."promotionid2"||'-'||b."promotionless2"||','
||b."promotionid3"||'-'||b."promotionless3"||','||b."promotionid4"||'-'||b."promotionless4"||','||b."promotionid5"||'-'||b."promotionless5"||

replace(a,'-0',''); a是你的字段!

------解决方案--------------------

探讨

case when promotionid1 is null then '' else promotionid1 end ||
case when promotionless1 is null then '' else '-' || promotionless1 || ',' end ||
...