mysql 查询后面每一条与前一条的差值

select

r1.id,

r1.addTime,

r1.weight,

(r1.weight - (select weight from table where addTime = MAX(r2.addTime))) as weightGain

from table r1 left outer join table r2 on r1.addTime > r2.addTime

where r1.DeleteMark = '0'

GROUP BY r1.addTime

ORDER BY r1.addTime;