特定时间内mysql记录的平均值

Question

I've got a mysql-database like this:

   ID | date | value
   1 | 2017-02-20 | 200
   2 | 2017-02-17 | 400
   3 | 2017-02-15 | 630
   4 | 2017-01-28 | 110
   5 | 2017-01-29 | 220

I know how to get the sum of january, february, ....

SELECT SUM(value) AS wert 
FROM table  
WHERE YEAR(date) = YEAR(CURRENT_DATE - INTERVAL 2 MONTH) 
  AND MONTH(date) = MONTH(CURRENT_DATE - INTERVAL 2 MONTH) 

But now I need a code to get the average of january and february.

I tried

SELECT SUM(value) AS wert, AVG(wert) as average 
FROM table  
WHERE YEAR (date) = YEAR(CURRENT_DATE - INTERVAL 2 MONTH) 
  AND MONTH(date) = MONTH(CURRENT_DATE - INTERVAL 2 MONTH) 

But this didn't work.

Thank you for your help!

Answer 1

WHERE date >= '2017-1-1' AND date < '2017-3-1'