Question

我有一个像这样的表

id | date_start | date_end
 1 | 2019.05.01 | 2019.05.06
 2 | 2019.05.05 | 2019.05.05
 3 | 2019.05.05 | 2019.05.08

Date_start和date_end表示在此期间该条目处于活动状态。是否有可能获得他的中间值活动条目数天？喜欢：

2019.05.01 | 1
2019.05.02 | 1
2019.05.03 | 1
2019.05.04 | 1
2019.05.05 | 3
2019.05.06 | 2
2019.05.07 | 1
2019.05.08 | 1

Answer 1

我认为这对您有用：

          SELECT temp_date, 
             COUNT(*) 
        FROM (
              SELECT ((SELECT MAX(date_start) FROM {dates_table}) - INTERVAL c.number DAY) AS temp_date
                FROM (SELECT singles + tens + hundreds number 
                        FROM ( SELECT 0 singles
                             UNION ALL SELECT   1 UNION ALL SELECT   2 UNION ALL SELECT   3
                             UNION ALL SELECT   4 UNION ALL SELECT   5 UNION ALL SELECT   6
                             UNION ALL SELECT   7 UNION ALL SELECT   8 UNION ALL SELECT   9
                             ) singles 
                        JOIN (SELECT 0 tens
                             UNION ALL SELECT  10 UNION ALL SELECT  20 UNION ALL SELECT  30
                             UNION ALL SELECT  40 UNION ALL SELECT  50 UNION ALL SELECT  60
                             UNION ALL SELECT  70 UNION ALL SELECT  80 UNION ALL SELECT  90
                             ) tens  
                        JOIN (SELECT 0 hundreds
                             UNION ALL SELECT  100 UNION ALL SELECT  200 UNION ALL SELECT  300
                             UNION ALL SELECT  400 UNION ALL SELECT  500 UNION ALL SELECT  600
                             UNION ALL SELECT  700 UNION ALL SELECT  800 UNION ALL SELECT  900
                             ) hundreds
                    ORDER BY number DESC) c  
               WHERE c.number BETWEEN 0 AND (SELECT DATEDIFF(MAX(date_end),MIN(date_start)) FROM {dates_table})
             ) calendar
        JOIN {dates_table} ON temp_date BETWEEN end_date AND start_date
    GROUP BY temp_date

只需用表名替换{dates_table}。

此生成日期系列的基础是从IvanD关于以下SO问题的答案中提取的：How to populate a table with a range of dates?

按日期对范围进行分组查询

1 个答案: