Question

我表格中的每一行都有一个日期时间戳，我希望从现在起查询数据库，计算过去30天内的行数，前30天的行数，依此类推。直到有30天的垃圾箱回到桌子的开头。

我已经成功地使用Python并进行了多次查询来执行此查询。但我几乎可以肯定它可以在一个MySQL查询中完成。

Answer 1

如果你只需要计算至少有一行的间隔，你可以使用它：

select
  datediff(curdate(), `date`) div 30 as block,
  count(*) as rows_per_block
from
  your_table
group by
  block

这也显示了开始日期和结束日期：

select
  datediff(curdate(), d) div 30 as block,
  date_sub(curdate(),
           INTERVAL (datediff(curdate(), `date`) div 30)*30 DAY) as start_block,
  date_sub(curdate(),
           INTERVAL (1+datediff(curdate(), `date`) div 30)*30-1 DAY) as end_block,
  count(*)
from your_table
group by block

但是如果你还需要显示所有间隔，你可以使用这样的解决方案：

select
  num,
  date_sub(curdate(),
           INTERVAL (num+1)*30-1 DAY) as start_block,
  date_sub(curdate(),
           INTERVAL num*30 DAY) as end_block,
  count(`date`)
from
  numbers left join your_table
  on `date` between date_sub(curdate(),
           INTERVAL (num+1)*30-1 DAY)  and
  date_sub(curdate(),
           INTERVAL num*30 DAY)
where num<=(datediff(curdate(), (select min(`date`) from your_table) ) div 30)
group by num

但是这需要您已准备好numbers表，或者请参阅fiddle here以获取没有数字表的解决方案。

Answer 2

在日期列上给出索引时，没有存储过程，临时表，只有一个查询和有效的执行计划：

select

  subdate(
    '2012-12-31',
    floor(dateDiff('2012-12-31', dateStampColumn) / 30) * 30 + 30 - 1
  ) as "period starting",

  subdate(
    '2012-12-31',
    floor(dateDiff('2012-12-31', dateStampColumn) / 30) * 30
  ) as "period ending",

  count(*)

from
  YOURTABLE
group by floor(dateDiff('2012-12-31', dateStampColumn) / 30);

除了这个咒语之外，这里发生的事情应该非常明显：

floor(dateDiff('2012-12-31', dateStampColumn) / 30)

该表达式多次出现，并且评估为30天前的dateStampColumn个数。 dateDiff返回以天为单位的差异，将其除以30以在30天内获得它，并将其全部提供给floor()以将其四舍五入为整数。一旦我们得到这个数字，我们可以GROUP BY它，并且我们进一步数学运算将这个数字转换回期间的开始和结束日期。

如果您愿意，请将'2012-12-31'替换为now()。以下是一些示例数据：

CREATE TABLE YOURTABLE
    (`Id` int, `dateStampColumn` datetime);

INSERT INTO YOURTABLE
    (`Id`, `dateStampColumn`)
VALUES
    (1, '2012-10-15 02:00:00'),
    (1, '2012-10-17 02:00:00'),
    (1, '2012-10-30 02:00:00'),
    (1, '2012-10-31 02:00:00'),
    (1, '2012-11-01 02:00:00'),
    (1, '2012-11-02 02:00:00'),
    (1, '2012-11-18 02:00:00'),
    (1, '2012-11-19 02:00:00'),
    (1, '2012-11-21 02:00:00'),
    (1, '2012-11-25 02:00:00'),
    (1, '2012-11-25 02:00:00'),
    (1, '2012-11-26 02:00:00'),
    (1, '2012-11-26 02:00:00'),
    (1, '2012-11-24 02:00:00'),
    (1, '2012-11-23 02:00:00'),
    (1, '2012-11-28 02:00:00'),
    (1, '2012-11-29 02:00:00'),
    (1, '2012-11-30 02:00:00'),
    (1, '2012-12-01 02:00:00'),
    (1, '2012-12-02 02:00:00'),
    (1, '2012-12-15 02:00:00'),
    (1, '2012-12-17 02:00:00'),
    (1, '2012-12-18 02:00:00'),
    (1, '2012-12-19 02:00:00'),
    (1, '2012-12-21 02:00:00'),
    (1, '2012-12-25 02:00:00'),
    (1, '2012-12-25 02:00:00'),
    (1, '2012-12-26 02:00:00'),
    (1, '2012-12-26 02:00:00'),
    (1, '2012-12-24 02:00:00'),
    (1, '2012-12-23 02:00:00'),
    (1, '2012-12-31 02:00:00'),
    (1, '2012-12-30 02:00:00'),
    (1, '2012-12-28 02:00:00'),
    (1, '2012-12-28 02:00:00'),
    (1, '2012-12-30 02:00:00');

结果：

period starting     period ending   count(*)
2012-12-02          2012-12-31      17
2012-11-02          2012-12-01      14
2012-10-03          2012-11-01      5

期间终点是包容性的。

在SQL Fiddle中播放。

有一些潜在的愚蠢，因为任何30天的零匹配行都不会包含在结果中。如果你可以在一个时期表中加入这个，那就可以消除。但是，MySQL没有像PostgreSQL generate_series()这样的东西，所以你必须在你的应用程序中处理它或尝试this clever hack。

Answer 3

试试这个：

SELECT 
  DATE_FORMAT(t1.`Date`, '%Y-%m-%d'),
  COUNT(t2.Id)
FROM 
(
  SELECT SUBDATE(CURDATE(), ID) `Date`
  FROM
  (
    SELECT  t2.digit * 10 + t1.digit + 1 AS id
    FROM         TEMP AS t1
    CROSS JOIN TEMP AS t2
  ) t 
  WHERE Id <= 30 
) t1
LEFT JOIN YOURTABLE t2 ON DATE(t1.`Date`) = DATE(t2.dateStampColumn)
GROUP BY t1.`Date`;

SQL Fiddle Demo

但是，您需要创建一个临时表Temp，如下所示：

CREATE TABLE TEMP 
(Digit int);
INSERT INTO Temp VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

Answer 4

请你试试以下内容：

SELECT Count(*)
FROM
  yourtable
where
  dateColumn between Now() and Now() - Interval 30 Day

它需要一些循环，以便更好地回答isolote返回所有30天的间隔。因为您还需要表格中的最小值（日期）和最后一个循环日期之间的30天间隔:)或者至少另一个带有每个30天间隔日期的表格，然后加入。

这是每个日历月的计数。不完全是你需要的。

SELECT
  extract(month from datecolumn),
  count(*)
FROM
  yourtable
GROUP BY
  extract(month from datecolumn);

考虑到后者的评论和Stefan的评论，这是一个很长的代码，但有适当的结果。基于我自己的示例数据，并与interval的MYSQL兼容。如果需要与SQL Server一起使用，请使用DateADD或quivalent function。

SQLFIDDLE

示例数据：

ID_MAIN  FIELD1  FILTER
----------------------------------------
1        red     August, 05 2012 00:00:00+0000
2        blue    September, 15 2012 00:00:00+0000
3        pink    September, 20 2012 00:00:00+0000
4        blue    September, 27 2012 00:00:00+0000
5        blue    October, 02 2012 00:00:00+0000
6        blue    October, 16 2012 00:00:00+0000
7        blue    October, 22 2012 00:00:00+0000
8        pink    November, 12 2012 00:00:00+0000
9        pink    November, 28 2012 00:00:00+0000
10       pink    December, 01 2012 00:00:00+0000
11       pink    December, 08 2012 00:00:00+0000
12       pink    December, 22 2012 00:00:00+0000

查询：

set @i:= 0;
SELECT MIN(filter) INTO @mindt
FROM MAIN
;
select
  count(a.id_main),
  y.dateInterval,
  (y.dateInterval - interval 29 day) as lowerBound
from
  main a join (
    SELECT date_format(Now(),'%Y-%m-%d') as dateInterval
    from dual
    union all
    select x.dateInterval
    from (
      SELECT
        date_format(
          DATE(DATE_ADD(Now(),
                        INTERVAL @i:=@i-29 DAY)),'%Y-%m-%d') AS dateInterval
      FROM Main, (SELECT @i:=0) r
      HAVING datediff(dateInterval,@mindt) >= 30
      order by dateInterval desc) as x) as y
  on a.filter <= y.dateInterval 
     and a.filter > (y.dateInterval - interval 29 day)
group by y.dateInterval
order by y.dateInterval desc
;

结果：

COUNT(A.ID_MAIN)    DATEINTERVAL    LOWERBOUND
----------------------------------------------
2                   2012-12-30  2012-12-01
3                   2012-12-01  2012-11-02
2                   2012-11-02  2012-10-04
4                   2012-10-04  2012-09-05

Answer 5

创建存储过程以计算30天的行数。

首先运行此过程，然后在想要生成数据时调用相同的过程。

DELIMITER $$

DROP PROCEDURE IF EXISTS `sp_CountDataByDays`$$

CREATE DEFINER=`root`@`localhost` PROCEDURE `sp_CountDataByDays`()
BEGIN 
    CREATE TEMPORARY TABLE daterange (
            id INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, 
            fromDate DATE, 
            toDate DATE, 
            PRIMARY KEY (`id`)
    ); 

    SELECT DATEDIFF(CURRENT_DATE(), dteCol) INTO @noOfDays 
    FROM yourTable ORDER BY dteCol LIMIT 1;

    SET @counter = -1;
    WHILE (@noOfDays > @counter) DO 
        INSERT daterange (toDate, fromDate) 
        VALUES (DATE_SUB(CURRENT_DATE(), INTERVAL @counter DAY), DATE_SUB(CURRENT_DATE(), INTERVAL @counter:=@counter + 30 DAY));
    END WHILE;

    SELECT d.id, d.fromdate, d.todate, COUNT(d.id) rowcnt 
    FROM daterange d  
    INNER JOIN yourTable a ON a.dteCol BETWEEN d.fromdate AND d.todate 
    GROUP BY d.id;

    DROP TABLE daterange;
END$$

DELIMITER ;

然后 CALL 程序：

CALL sp_CountDataByDays();

您可以获得如下输出：

ID  From Date   To Date     Row Count
1   2012-12-06  2013-01-05  17668
2   2012-11-06  2012-12-06  2845
3   2012-10-07  2012-11-06  2276
4   2012-09-07  2012-10-07  4561
5   2012-08-08  2012-09-07  5415
6   2012-07-09  2012-08-08  8954
7   2012-06-09  2012-07-09  4387
8   2012-05-10  2012-06-09  7911
9   2012-04-10  2012-05-10  7935
10  2012-03-11  2012-04-10  2566

计算30天垃圾箱中的行数

5 个答案:

SQL Fiddle Demo