如何选择行总价小于500且大于450的随机行？

Question

Table orders:

id          month          price
-------------------------------------- 
1           12             74.00
2           11             27.00
3           12             35.00
4           12             85.00
5           12             38.00
6           04             45.00
7           03             27.00
8           12             23.00
9           12             45.00
10          03             36.00
11          12             67.00
12          06             45.00
13          12             23.00
14          12             35.00

How to select random rows from orders where month = 12 and sum of selected rows is less than 150 AND greater than 100 ?

or that the sum is max 150...

One of the desired results (sum 147.00):

id          month          price
-------------------------------------- 
1           12             74.00
5           12             38.00
14          12             35.00

example for other desired result (sum 131.00):

id          month          price
-------------------------------------- 
3           12             35.00
5           12             38.00
8           12             23.00
14          12             35.00

I tried something like this, but unsuccessfully:

SELECT id,month,price,SUM(price) 
FROM orders 
WHERE month = '12' AND SUM(price) < 150 AND SUM(price) > 100
ORDER BY rand()

please help me

Answer 1

This is a complicated question. You need to do a cumulative sum on the random rows and then choose an arbitrary value.

This gets you the limit of less than 150:

SELECT o.*
FROM (SELECT o.*, @cumep := (@cum3p + price) as cumep
      FROM orders o CROSS JOIN (SELECT @cumep := 0) params
      WHERE month = 12
      ORDER BY rand()
     ) o
WHERE cumep < 150;