mysql - MySql 选择所需的指导

Question

你好，我有一张这样的 table

Activity     Date
---------------------
0          2012-11-20
1          2012-11-20
1          2012-11-20
1          2012-11-21
1          2012-11-21
0          2012-11-22

我需要选择记录为

 Day-wise total   0's    1's    Date  
------------------------------------------
     3             1      2     2012-11-20
     2             0      2     2012-11-21
     1             1      0     2012-11-22

Answer 1

您需要的是一个GROUP BY date、COUNT(Activity) 来获取每日总计和一个CASE 表达式来转换1 和 0 的值。我在这里使用了 SUM 但它的行为就像 COUNT 一样:

SELECT
  COUNT(Activity) AS "Day-wise total",
  SUM(CASE WHEN Activity = 0 THEN 1 ELSE 0 END) AS "0's",
  SUM(CASE WHEN Activity = 1 THEN 1 ELSE 0 END) AS "1's",
  `Date` AS "Date"
FROM Table
GROUP BY `Date`;

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