Question

我有一张桌子，他跟随着以下字段：

-id---start_date(datetime)---end_date(datetime)-
-1---02/11/13 4:00---02/11/13 5:00-
-2---02/12/13 4:00---02/12/13 5:00-
-3---02/11/13 5:00---02/11/13 6:00-
-4---03/11/13 4:00---03/11/13 5:00-
-5---02/11/13 3:00---02/14/13 3:00-

我想计算一天中每天有多少条记录，从start_date开始到另一end_date结束。
例如，在02/10/13和03/10/13之间选择：

-count---day(datetime)-
-3---02/11/13-
-2---02/12/13-
-1---02/13/13-
-1---02/14/14-

谢谢！
如果我想在主表中添加一个字段与每个记录的频率？
例如：
频率
0：一次性;
1：每天;
7：每周;
等...

 -id---start_date(datetime)---end_date(datetime)---frequency-
-1---02/11/13 4:00---02/11/13 5:00---7-
-2---02/12/13 4:00---02/12/13 5:00---0-
-3---02/11/13 5:00---02/11/13 6:00---0-
-4---03/11/13 4:00---03/11/13 5:00---0-
-5---02/11/13 3:00---02/14/13 3:00---0-

结果：

-count---day(datetime)-
-3---02/11/13-
-2---02/12/13-
-1---02/13/13-
-1---02/14/14-
-1---02/18/14-
-1---02/25/14-
-1---03/04/14-

Answer 1

对数据格式和表格做出一些假设： -

SELECT aDate, COUNT(SomeDateTable.id)
FROM
(
    SELECT DATE_ADD("2013-02-10", INTERVAL (Hundreds.i * 100 + Tens.i * 10 + Units.i) DAY) AS aDate
    FROM
    (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) Units,
    (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) Tens,
    (SELECT 0 AS i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9) Hundreds
    WHERE DATE_ADD("2013-02-10", INTERVAL (Hundreds.i * 100 + Tens.i * 10 + Units.i) DAY) <= "2013-03-10"
) sub1
INNER JOIN SomeDateTable
ON sub1.aDate BETWEEN DATE(SomeDateTable.start_date) AND DATE(SomeDateTable.end_date)
GROUP BY aDate;

这将处理最多1000天的日期范围

SQL在这里小提琴： -

http://www.sqlfiddle.com/#!2/103b7/1

Mysql - 按月计数元素

1 个答案: