将一个VALUE等于DB中的两个字段相连接的where条件

cmd.CommandText = String.Format("select sum(INV_QUANTITY) as sl from DMS_INVENTORY_TEMP " + _
            " where ('{0}'=org_num||customer_num) and INV_date='{1}' ", search, rqsj)
// search=org_num+customer_num