mysql - 每天计数(mysql)

I want get something like this

MySQL数据

(dat_reg)
1.1.2000
1.1.2000
1.1.2000
2.1.2000
2.1.2000
3.1.2000

我想得到：

   (dat_reg)  (count)
    1.1.2000 -   3
    2.1.2000 -   5
    3.1.2000 -   6

我试过的是：

SELECT COUNT( * ) as a , DATE_FORMAT( dat_reg, '%d.%m.%Y' ) AS dat
FROM members
WHERE (dat_reg > DATE_SUB(NOW() , INTERVAL 5 DAY))
GROUP BY DATE_FORMAT(dat_reg, '%d.%m.%Y')
ORDER BY dat_reg

但我得到：

 1.1.2000 - 3 | 2.1.2000 - 2 | 3.1.2000 - 1

一些技巧，如何为此创建查询？

最佳答案

我建议在MySQL中使用变量：

SELECT d.*, (@sumc := @sumc + cnt) as running_cnt
FROM (SELECT DATE_FORMAT(dat_reg, '%d.%m.%Y') as dat, COUNT(*) as cnt
      FROM members
      WHERE dat_reg > DATE_SUB(NOW() , INTERVAL 5 DAY)
      GROUP BY dat
      ORDER BY dat_reg
     ) d CROSS JOIN
     (SELECT @sumc := 0) params;

如果要从一开始就进行累加，则需要一个附加的子查询：

SELECT d.*
FROM (SELECT d.*, (@sumc := @sumc + cnt) as running_cnt
      FROM (SELECT DATE_FORMAT(dat_reg, '%d.%m.%Y') as dat, dat_reg, COUNT(*) as cnt
            FROM members
            GROUP BY dat
            ORDER BY dat_reg
           ) d CROSS JOIN
           (SELECT @sumc := 0) params
      ) d
WHERE dat_reg > DATE_SUB(NOW() , INTERVAL 5 DAY)

关于mysql - 每天计数(mysql)，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/51219026/