Some useful queries of the ORA db to get usage stats

How many peer grades submitted per problem?

SELECT
	problem_id,
	course_id,
	count(*) AS peergrades
FROM
	controller_submission cs,
	controller_grader cg
WHERE
	cs.id  = cg.submission_id
AND cg.grader_type = "PE"
GROUP BY
	cs.course_id,
	cs.problem_id;

How many submissions per problem?

SELECT
	course_id,
	problem_id,
	count(*) AS submissions
FROM
	controller_submission
GROUP BY
	course_id,
	problem_id;