Clean and consice code
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```mysql []
# Write your MySQL query statement below
select 
    p.product_id , 
    ifNull(Round(sum(p.price*u.units)/sum(units),2),0) as  average_price 
from 
    Prices p left join UnitsSold u 
    on p.product_id = u.product_id
and 
    u.purchase_date >= p.start_date 
and 
    u.purchase_date <= p.end_date
group by(p.product_id);
```
['MySQL']