SQL Quest

Lessons, hints, explained solutions, the in-browser PostgreSQL editor and practice answer checks in your browser are available. Graded assessments, recorded progress from answer checks and new certificates aren't available yet.

Analyst skills assessment

Ten realistic analyst requests across retail, banking, healthcare, logistics, HR and SaaS data, in 45 minutes. Each attempt draws one question for each of ten skills: date and pattern filters, conditional aggregation, business summaries, joins with aggregation, finding rows without a match, correlated subqueries, LAG and LEAD, top-N per group and standardising messy values. Answers are graded on the public data and on a hidden copy with different rows, so they must express the rule, not the numbers. Pass mark 75%.

Questions
10 drawn from 20
Time
45 minutes
Pass mark
75%
Retake
after 12 hours

How it works

  • Questions are drawn at random across the skills below, easiest first. A retake avoids the questions of your previous attempt wherever the question bank has others for that skill.
  • You can run queries on the real dataset as often as you like. Answers save as you type; nothing is graded until you submit.
  • The timer is kept on the server and covers writing your answers. When time runs out, your saved answers are graded as they are.
  • A query that errors or runs longer than the grader's time limit counts as not correct. A problem on our side (for example the grader being busy) never does: the attempt stays open with your answers saved, and you can submit again.
  • Each answer is graded by results on the dataset and on a hidden copy with different rows. Afterwards you see which answers passed, with the model solution and an explanation.
  • It's open-book and not proctored.

Skills covered

  • Filtering dates and numbers
  • LIKE, ILIKE and pattern matching
  • Conditional aggregation
  • Business summaries and KPIs
  • Aggregating after joins
  • Finding rows without a match
  • Correlated subqueries
  • LAG and LEAD
  • Top-N per group
  • Standardizing inconsistent values
Not available yet. Graded assessments aren't available yet: they need SQL Quest's server-side grader, which is switched off until its security review is complete. You can still practise every lesson and check practice answers in your browser.