mysql - 表中没有数据的日期的移动平均值

Question

您好，我有以下表格数据，我正在寻找移动平均线。

原始数据

date    qty 
06/11/15    5   
08/11/15    7   
09/11/15    8   
10/11/15    12  
11/11/15    34  
15/11/15    45  
16/11/15    12  
17/11/15    7   

移动平均线应考虑最近 90 天的数据，并给出当前数据的平均值，如下所示

Moving Average Data     
date    qty movingAvg
06/11/15    5   5
07/11/15    0   2.5
08/11/15    7   4
09/11/15    8   5
10/11/15    12  6.4
11/11/15    34  11
12/11/15    0   9.43
13/11/15    0   8.25
14/11/15    0   7.33
15/11/15    45  11.1
16/11/15    12  11.18
17/11/15    7   10.83

我正在使用的查询

SELECT t1.date,t1.qty, AVG(t2.qty) AS 'movingAvg'
FROM tbl t1
JOIN tbl t2 ON t1.company_id=t2.company_id 
AND DATEDIFF(t1.date, t2.date) BETWEEN 0 AND 90
WHERE t1.company_id=1234
GROUP BY t1.date
ORDER BY t1.date;

这是忽略日期而不输入，我也想包括它们。

Answer 1

像这样使用 MySQL Str_to_date

Str_to_date(t1.date,'%d/%m/%y')

或更改此

DATEDIFF(Str_to_date(t1.date,'%d/%m/%y'), Str_to_date(t2.date,'%d/%m/%y'))

MySQL STR_TO_DATE() function to convert a string into a date time value