Question

我有两列，一个时间戳和一个已选择卡的号码。

card      added
1         2016-09-23 13:48:48
3         2016-09-23 13:48:48
1         2016-09-23 13:48:48
2         2016-09-24 13:48:48
1         2016-09-24 13:48:48
2         2016-09-24 13:48:48
3         2016-09-24 13:48:48

我需要的输出是每张卡的数量，按条目分组，如下所示：

card      count     added
1         2         2016-09-23
3         1         2016-09-23
1         1         2016-09-24
2         2         2016-09-24
3         1         2016-09-24

所以我想我必须计算添加的卡是相同的。但是我不知道怎么做，而且我需要按照每个添加的卡进行分组。

Answer 1

您需要按照卡片和截断日期对结果进行分组。可以通过调用date()：

来完成截断

SELECT   card, DATE(added) AS added, COUNT(*)
FROM     mytable
GROUP BY card, DATE(added)

Answer 2

您只需要GROUP BY卡片和日期：

SELECT card, COUNT(*), CAST(added AS date) added
FROM your_table
GROUP BY card, CAST(added AS date)

Answer 3

SELECT card, COUNT(card) AS CNT, added
FROM `example_table`
GROUP BY card, added
ORDER BY added ASC, card ASC

MYSQL查询：按日期和计数条目分组

3 个答案: