9 - 上升的温度

-- 找出与之前（昨天的）日期相比温度更高的所有日期的 id
-- DATEDIFF('2007-12-31','2007-12-30');   # 1
-- DATEDIFF('2010-12-30','2010-12-31');   # -1select w1.id 
from Weather w1, Weather w2
wheredatediff(w1.recordDate,w2.recordDate)=1 and w1.temperature>w2.temperature;