DATEDIFF 函数用于计算两个日期之间的差值，以天为单位

• DATEDIFF 函数返回一个整数，表示 date1 和 date2 之间的天数。如果 date1 在 date2 之前，结果为负数；如果在 date2 之后，结果为正数；如果相等，则结果为零。

SELECT  t.id
FROM    Weather AS t
JOIN    Weather AS y
ON      DATEDIFF(t.recordDate, y.recordDate) = 1
WHERE   t.temperature > y.temperature;

SELECT  t.id
FROM    Weather AS t,Weather AS y
WHERE   DATEDIFF(t.recordDate, y.recordDate) = 1ANDt.temperature > y.temperature;