Is it possible to calculate something involve datetime and number in MySQL with some conditions?

I have a table comment and a table price like below. The key columns in both tables are ticker_id, price_datetime and price_open. The last column threshold in table comment (which currently NULL) is something that I need to fill in with after some calculation queries (if this is achievable).

comment table:

+------------+---------------------+--------+---------+-----------+---------------------+------------+-----------+
| comment_id | comment_datetime    | author | comment | ticker_id | price_datetime      | price_open | threshold |
+------------+---------------------+--------+---------+-----------+---------------------+------------+-----------+
| 1          | 2014-09-22 06:05:00 | A1     | C1      | 343       | 2014-09-22 08:00:00 | 53.25000   |           |
+------------+---------------------+--------+---------+-----------+---------------------+------------+-----------+
| 2          | 2014-09-22 06:39:00 | A2     | C2      | 1         | 2014-09-22 08:00:00 | 62.00000   |           |
+------------+---------------------+--------+---------+-----------+---------------------+------------+-----------+
| 3          | 2014-09-22 08:13:00 | A3     | C3      | 178       | 2014-09-22 08:13:00 | 5.15000    |           |
+------------+---------------------+--------+---------+-----------+---------------------+------------+-----------+

price table:

+----------+---------------------+------------+-----------+
| price_id | price_datetime      | price_open | ticker_id |
+----------+---------------------+------------+-----------+
| 1        | 2014-09-22 08:01:00 | 62.00000   | 1         |
+----------+---------------------+------------+-----------+
| 2        | 2014-09-22 08:02:00 | 62.00000   | 1         |
+----------+---------------------+------------+-----------+
| 3        | 2014-09-22 08:03:00 | 62.00000   | 1         |
+----------+---------------------+------------+-----------+

In each row of table comment, price_open will be used as "base price".

• 
  

  For each row of table comment

  
  
  
  
  • Match the ticker_id, price_datetime and price_open with table price
  
  
  • Then, get the +-2 days for each price_datetime (follows with the price_open)
  
  
  • Then, count whether any of the price.price_open within that 5 days exceeds 5%, 10% or 15% of the "base price"
  
  
  
  


• 
  

  Conditions:

  
  
  
  
  • If any of the price.price_open within that 5 days equals/exceeds 15% of the "base price", then fill in comment.threshold with "R"
  
  
  • If any of the price.price_open within that 5 days equals/exceeds 10% of the "base price" (but less than 15%), then fill in comment.threshold with "A"
  
  
  • If any of the price.price_open within that 5 days equals/exceeds 5% of the "base price" (but less than 10%), then fill in comment.threshold with "Y"
  
  
  • If any of the price.price_open within that 5 days is less 5%, then fill in comment.threshold with "C"
  
  
  • For empty values in columns comment.price_datetime and comment.price_open, we will leave it NULL as it is, thus NULL for comment.threshold as well.
  
  
  
  

Is the above going to be achievable in MySQL using JOIN? I am trying to learn about JOIN right now, unfortunately it seems way too complicated to me, I have no clue about the query that I should execute as I just started learning MySQL.

I've tried explaining my question in details, but if there's anything unclear, kindly let me know.

Any help would be much appreciated. Thank you.