各种时间段的SQL查询

Question

我有一个包含以下条目的表：

completed_time||   BOOK_CNT
*********************************************
2013-07-23    | 2
2013-07-22    | 1
2013-07-19    | 3
2013-07 16    |5
2013-07-12    |4
2013-07-11    |2
2013-07-02    |9
2013-06-30    |5

现在，我想使用上面的条目进行数据分析。

让我们说DAYS_FROM，DAYS_TO和PERIOD是三个变量。

我需要点击以下类型的查询：

“在PERIOD区间内从DAYS_FROM到DAYS_TO的总图书。”

DAYS_FROM 是格式为YYYY-MM-DD的日期

， DAYS_TO 是格式为YYYY-MM-DD的日期

PERIOD 是{1W，2W，1M，2M，1Y}  其中W，M，Y代表WEEK，MONTH和YEAR。

示例：查询DAYS_FROM = 2013-07-23，DAYS_TO = 2013-07-03和PERIOD = 1W应返回：

ith week - total
1 -        3
2-         8
3-         6 
4-         14

解释：

1-3 means (The total book from 2013-07-21(sun) to 2013-07-23(tue) is 3 )
2-8 means (The total book from 2013-07-14(sun) to 2013-07-21(sun) is 8 )
3-16 means (The total book from 2013-07-07(sun) to 2013-07-14(sun) is 6 )
4-14 means (The total book from 2013-07-03(wed) to 2013-07-07(sun) is 14 )

请参阅日历图片以便更好地理解。

如何触发此类查询？

我尝试了什么？

 SELECT DAY(completed_time), COUNT(total) AS Total
  FROM my_tab
 WHERE completed_time BETWEEN '2013-07-23' - INTERVAL 1 WEEK AND '2013-07-03'
 GROUP BY DAY(completed_time);

以上查询从2013-07-23减去7天后被视为 2013-07-16至2013-07-23 为第一周， 2013-07-09至2013-07-16 为第二周等等。

Answer 1

一个简单的起点如下所示，当然您可能需要调整ith值以满足您的需求;

SET @period='1M';

SELECT CASE WHEN @period='1Y' THEN YEAR(completed_time) 
            WHEN @period='1M' THEN YEAR(completed_time)*100+MONTH(completed_time)
            WHEN @period='2M' THEN FLOOR((YEAR(completed_time)*100+MONTH(completed_time))/2)*2
            WHEN @period='1W' THEN YEARWEEK(completed_time)
            WHEN @period='2W' THEN FLOOR(YEARWEEK(completed_time)/2)*2
       END ith,
       SUM(BOOK_CNT) Total
FROM my_tab
GROUP BY ith
ORDER BY ith DESC;

An SQLfiddle to test with