select sum(case when column> 0 then column else 0 end) as u0,
sum(case when column <0 then column else 0 end ) as d0 from tablename
select sum(case when column> 0 then column else 0 end) as u0,
sum(case when column <0 then column else 0 end ) as d0 from tablename
![【MySQL数据库】数据库索引事务1.索引2.事务[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)