MySQL:选择日期范围之间的所有日期，并获取匹配日期的表数据 [英] MySQL: Select all dates between date range and get table data matching dates

问题描述

有一个表，其中包含这样的数据:

There is a table which has data as such:

-----------------------
|   id   |    date    |
-----------------------
|   1    | 2016-07-11 |
|   2    | 2016-07-11 |
|   3    | 2016-07-15 |
|   4    | 2016-07-15 |
|   5    | 2016-07-15 |
|   6    | 2016-07-16 |
|   7    | 2016-07-19 |
|   8    | 2016-07-20 |
-----------------------

我想获取一个日期范围(所有日期)和每个日期的ID计数，如果不存在任何记录，则返回0.

I want to get a date range (all dates) and the count of IDs for each date, returning 0 when no records exist.

如果运行日期为2016年7月10日至2016年7月20日，则结果应如下所示:

If run for dates between 2016-07-10 to 2016-07-20, the result should look like this:

--------------------------
|    date    | count(id) |
--------------------------
| 2016-07-10 |     0     |
| 2016-07-11 |     2     |
| 2016-07-12 |     0     |
| 2016-07-13 |     0     |
| 2016-07-14 |     0     |
| 2016-07-15 |     3     |
| 2016-07-16 |     1     |
| 2016-07-17 |     0     |
| 2016-07-18 |     0     |
| 2016-07-19 |     1     |
| 2016-07-20 |     1     |
--------------------------

我已经找到了

I've found solutions for getting a date range but couldn't figure out how to get it to count the IDs that exist for those dates within a table.

谢谢！

推荐答案

我通过修改解决方案中给出的查询以获取所有日期来解决这个问题.

I figured this out by modifying the query given in the solution for getting all dates.

以下查询返回所有日期，以及是否存在记录的ID计数:

The following query returns all dates, and counts of the IDs if any records exist:

select d.date, count(v.id) from 
(select adddate('1970-01-01',t4.i*10000 + t3.i*1000 + t2.i*100 + t1.i*10 + t0.i) date from
 (select 0 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) t0,
 (select 0 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) t1,
 (select 0 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) t2,
 (select 0 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) t3,
 (select 0 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) t4) d
left join visitors v on d.date = v.date
where d.date between '2016-06-01' and '2016-06-30'
group by d.date
order by d.date

要获取日期范围，请访问 @ mark-bannister ，并在查询上进行简单的联接以匹配结果，排序即可找到解决方案.

Courtesy for getting the dates range goes to @mark-bannister and a simple join on the query matching for results, and sorting gets the solution.

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