MySQL How do I create this subquery?

Question

I have the following tables

Table Farm

+---------+--------+-------------------+-----------+------------+
| FARM_ID |Stock_ID| FARM_T         


        

Answer 1

Here is the query I've been working on. However, the results are slighly different from the ones you've posted in your question:

select o.origin_name, s.stock_title, sum(
  case f.size
    when 'H' then
      case
        when sizes = 'H,L,M' then 70
        when sizes = 'H,M' then 80
        when sizes = 'H,L' then 90
        when sizes = 'H' then 100
        else 0
      end
    when 'M' then
      case
        when sizes = 'H,L,M' then 20
        when sizes = 'H,M' then 20
        when sizes = 'L,M' then 60
        when sizes = 'M' then 100
        else 0
      end
    else
      case
        when sizes = 'H,L,M' then 10
        when sizes = 'L,M' then 40
        when sizes = 'H,L' then 10
        when sizes = 'L' then 100
        else 0
      end
  end * r.score / 100) FinalScore
from farm f
join (
  select f.stock_id, group_concat(distinct f.size order by f.size) sizes
  from farm f
  join results r on f.farm_id = r.farm_id
  group by f.stock_id
) stockSizes on f.stock_id = stockSizes.stock_id
join results r on f.farm_id = r.farm_id
join (
  select f.stock_id, r.gate_id
  from results r
  join farm f on r.farm_id = f.farm_id
  group by f.stock_id, r.gate_id
  having sum(r.score = 0) = 0
) FullGates
on FullGates.stock_id = f.stock_id and FullGates.gate_id = r.gate_id
join stock s on s.stock_id = f.stock_id
join origin o on o.origin_id = s.origin_id
group by o.origin_id, s.stock_id

Result:

+-------------+-------------+------------+
| ORIGIN_NAME | STOCK_TITLE | FINALSCORE |
+-------------+-------------+------------+
| US          | P1          |         93 |
| CA          | P3          |         90 |
| MX          | Q4          |        100 |
| MX          | B3          |        100 |
+-------------+-------------+------------+

Let me know if this did the trick.

Answer 2

I would take your original query to get the second last table and change the Select by adding use distinct (found here) and only select Origin, Stock and the calculation for the Score. For example if the score is an average of all of them it would be AVG(Score) where Score would be what you fetched in the original query. If you want to use only a small subset of the items that have the same Origin and Stock to calculate the Score I would use a subquery, with the where matching the Origin and Stick ids, in the select so you have:

Select Origin, 
       Stock, 
       (select calculation(Score) from tables where tables.stock_id = .... tables.origin_id = .....)
From....

Hope this helps.