日本搞逼视频_黄色一级片免费在线观看_色99久久_性明星video另类hd_欧美77_综合在线视频

國內(nèi)最全IT社區(qū)平臺 聯(lián)系我們 | 收藏本站
阿里云優(yōu)惠2
您當前位置:首頁 > 數(shù)據(jù)庫 > 數(shù)據(jù)庫應(yīng)用 > Rising Temperature

Rising Temperature

來源:程序員人生   發(fā)布時間:2015-06-04 07:51:18 閱讀次數(shù):3123次
    Given a Weather table, write a SQL query to find all dates' Ids with higher temperature compared to its previous (yesterday's) dates.

    +---------+------------+------------------+
    | Id(INT) | Date(DATE) | Temperature(INT) |
    +---------+------------+------------------+
    |       1 | 2015-01-01 |               10 |
    |       2 | 2015-01-02 |               25 |
    |       3 | 2015-01-03 |               20 |
    |       4 | 2015-01-04 |               30 |
    +---------+------------+------------------+
    For example, return the following Ids for the above Weather table:
    +----+
    | Id |
    +----+
    |  2 |
    |  4 |
    +----+
    思想:需要知道兩個變量,首先是前后兩個date的差,然后是前后兩個date之間的溫差。
        1、select * from weather
            +------+------------+-------------+
            | id   | date       | temperature |
            +------+------------+-------------+
            |    1 | 2000⑴2⑴5 |           3 |
            |    2 | 2000⑴2⑴6 |           5 |
            |    3 | 2000⑴2⑴7 |           1 |
            |    4 | 2000⑴2⑴4 |           5 |
            |    5 | 2000⑴2⑴8 |           0 |
            +------+------------+-------------+
        2、排序
            mysql> select * from Weather order by date;
            +------+------------+-------------+
            | id   | date       | temperature |
            +------+------------+-------------+
            |    4 | 2000⑴2⑴4 |           5 |
            |    1 | 2000⑴2⑴5 |           3 |
            |    2 | 2000⑴2⑴6 |           5 |
            |    3 | 2000⑴2⑴7 |           1 |
            |    5 | 2000⑴2⑴8 |           0 |
            +------+------------+-------------+
        3、獲得溫度差和時間差
        select id,datediff(date,@predate) as datediff,temperature,@tempdiff:=temperature-@pretemp as 'tempdiff',@pretemp:=temperature as 'pretemp' ,@predate:=date  as 'predate' from (select * from Weather order by date ) t,(select @predate := '1000-01-01') l,(select @pretemp:=0) pret;
            +------+----------+-------------+----------+---------+------------+
            | id   | datediff | temperature | tempdiff | pretemp | predate    |
            +------+----------+-------------+----------+---------+------------+
            |    4 |   365590 |           5 |        5 |       5 | 2000⑴2⑴4 |
            |    1 |        1 |           3 |       ⑵ |       3 | 2000⑴2⑴5 |
            |    2 |        1 |           5 |        2 |       5 | 2000⑴2⑴6 |
            |    3 |        1 |           1 |       ⑷ |       1 | 2000⑴2⑴7 |
            |    5 |        1 |           0 |       ⑴ |       0 | 2000⑴2⑴8 |
            +------+----------+-------------+----------+---------+------------+ 
        4、提取id
        select id  from (
            select * from(
                select id,datediff(date,@predate) as diff,temperature,@tempdiff:=temperature-@pretemp as 'tempdiff',@pretemp:=temperature as 'pretemp' ,@predate:=date  as 'predate'
                from (select * from Weather order by date ) h
            ) t,(select @predate := '1000-01-01') l,(select @pretemp:=0) pret) w 
            where w.diff=1 and w.tempdiff>0;
            +------+
            | id   |
            +------+
            |    2 |
            +------+
生活不易,碼農(nóng)辛苦
如果您覺得本網(wǎng)站對您的學習有所幫助,可以手機掃描二維碼進行捐贈
程序員人生
------分隔線----------------------------
分享到:
------分隔線----------------------------
關(guān)閉
程序員人生
主站蜘蛛池模板: 久久久久久国产 | 美女视频黄免费 | 国产二区久久 | 久久久国产一区二区三区四区小说 | 国产精品久久久久久久久久久免费看 | 欧美激情一区 | 中文字幕一区二区三区在线视频 | 国产精品自产拍在线观看桃花 | 欧美一区二区三区公司 | 日韩成人精品视频 | 中文天堂视频在线 | 成人性生交大片免费看视频r | 在线视频日韩精品 | 国产精品美女久久久久aⅴ国产馆 | 国产激情综合 | 欧美 日韩 综合 | 日韩欧美精品在线 | 99精品热视频 | 日韩精品一区二区三区在线播放 | 久久久久久国产 | 精品一二三区视频 | 偷自拍视频区综合视频区 | 日韩高清免费观看 | 欧美一区二区在线看 | 国产区一区 | 中文字幕在线不卡视频 | 久久精品国产清自在天天线 | 国产视频在线一区二区 | 午夜精品久久久久久久白皮肤 | 亚洲精品乱码久久久久久蜜桃动漫 | 国内精品久久久久影院薰衣草 | 99精品视频在线观看 | 久九九 | 免费在线观看91 | 久久97视频| 日韩中文字幕在线观看 | 久久免费少妇 | 欧美一区二区在线视频 | 日韩一级免费 | 久久精品夜夜夜夜夜久久 | 天天摸夜夜 |