同一个表,用sql查询今天和昨天的差值,然后排序,要怎么做

WBOY
Libérer: 2016-09-01 00:20:19
original
1858 Les gens l'ont consulté

比较快的写法是什么

我现在用left join 这个表本身,但是结果好像不对

SELECT

<code>            table.id ,SUM(table.s-yestoday.a) as sum
            FROM table
            LEFT JOIN table yestoday
            ON yestoday.uid = wy_appdata.uid
            WHERE table.year = '.$year.' AND table.month = '.$month.' AND table.day = '.$day.' AND yestoday.year = '.$bre_data['year'] .' AND yestoday.month ='.$bre_data['month'] .' AND yestoday.day = '.$bre_data['day'] .'
            GROUP BY table.uid
            ORDER BY sum DESC</code>
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回复内容:

比较快的写法是什么

我现在用left join 这个表本身,但是结果好像不对

SELECT

<code>            table.id ,SUM(table.s-yestoday.a) as sum
            FROM table
            LEFT JOIN table yestoday
            ON yestoday.uid = wy_appdata.uid
            WHERE table.year = '.$year.' AND table.month = '.$month.' AND table.day = '.$day.' AND yestoday.year = '.$bre_data['year'] .' AND yestoday.month ='.$bre_data['month'] .' AND yestoday.day = '.$bre_data['day'] .'
            GROUP BY table.uid
            ORDER BY sum DESC</code>
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假设有如下数据表tbl

uid s date
1 5 2016-08-31
2 3 2016-08-31
3 7 2016-08-31
1 2 2016-08-30
2 5 2016-08-30
4 4 2016-08-30

运行

<code class="sql">SELECT
  today.uid,
  today.s - IFNULL(yesterday.s, 0) AS diff
FROM
  (SELECT uid, SUM(s) AS s FROM tbl WHERE date='2016-08-31' GROUP BY uid) AS today
LEFT OUTER JOIN
  (SELECT uid, SUM(s) AS s FROM tbl WHERE date='2016-08-30' GROUP BY uid) AS yesterday
USING (uid)
ORDER BY diff DESC;</code>
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结果

uid diff
3 7
1 3
2 -2
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