it's just SQL

oh ya I forgot to tag <@&435155896780324864>

I ended up writing my own solution like this

```SQL
SELECT BOOKS.Title, BOOKS.Category, BOOKS.Cost
FROM BOOKS, (SELECT BOOKS.Category, AVG(BOOKS.Cost) AverageCost
FROM BOOKS
GROUP BY BOOKS.Category) AverageCosts
WHERE BOOKS.Category = AverageCosts.Category
AND BOOKS.Cost < AverageCosts.AverageCost
```

idk if the first one is better

mine feels less convoluted

@Jacob I agree yours is less convoluted that the first one, but I would do
```sql
SELECT Title, Category, Cost FROM
(
BOOKS
INNER JOIN
(
SELECT Category, AVG(Cost) as avg_cost FROM
BOOKS GROUP BY Category
)
)
WHERE Cost < avg_cost
```

haha wow that's a lot less

I think our teacher wants us to get practice with subqueries on this assignment, though

@Jacob well the avg cost part is calculated with a subquery

oh that's right

I don't think we officially learned to do subqueries in the JOIN clause yet

but that looks like a better solution for the future, thanks

Pretty cool article: https://www.sciencehistory.org/distillations/magazine/isaac-newton-and-the-american-alchemist