I have a table app_order with fields price (a number) and side (side can be either ‘up’ or ‘down’).

I need to write a postgreSQL condition within a WHERE clause that filters app_order entries where price is both:

1. bigger than the average of 2 prices (max price with side=’up’ and min price with side=’down’) – 1 AND

2. smaller than the average of 2 prices (max price with side=’up’ and min price with side=’down’) + 1

How can I concatenate where conditions to do this?

At the end, I need a query similar to this:

SELECT
  market AS "MARKET",
  SUM(size*price) AS "SUM"
FROM
  app_order
WHERE
  --Missing condition here AND
GROUP BY
  market
ORDER BY
  market ASC

Thanks a lot!