Stage 1: retrieve and filter
Practise SELECT, aliases, WHERE, CASE, NULL handling, ORDER BY, and LIMIT. Write queries that another person can read and explain.
Stage 2: joins and grain
Understand primary keys, one-to-many relationships, inner versus outer joins, and duplicate rows. State the expected grain before joining tables.
Stage 3: aggregation
Use GROUP BY, HAVING, conditional aggregation, and date grouping to answer business questions. Keep metric definitions beside the query.
Stage 4: advanced analysis
Learn CTEs, subqueries, window functions, ranking, running totals, and cohort-style comparisons. Use EXPLAIN or the platform’s equivalent when performance matters.
Stage 5: analyst project
Choose a dataset, define a question, write a query plan, validate the result, and communicate the recommendation. Continue with data project briefs and the analyst career guide.
Build SQL and BI together
Review the ISS Data & Business Intelligence programme.
View Data & BI curriculum →Editorial scope
SQL syntax varies across engines. Check the documentation for the database you use.