[tetromino_]

By implementing only that 1% of a real database's functionality that this task requires. Consider: you have only one table, no updates or deletes or transactions, fixed schema, and very, very simple queries.

So it's just a matter of parsing the CSV into some native data structure in your favorite language and then computing sort indices of the columns by which rows might be queried.

[infinite8s]

And sadly you don't even need to create sort indices. Just reading the data into a list of tuples and a few list comprehensions would provide all the querying needed (it wouldn't be efficient but most candidates can't even get that far)