怎么在left里面的where加if select sum(num) num from dm a left join (SELECT ono,type FROM dm_cus where(如果type参数为空,type is null,type) GROUP BY ono,type ) b on b.ono = a.ono where data_date>= '${startTime}' AND data_date<='${endTime}' ${if(len(type)=0,"","and type in ('"+type+"')")} |