#Query

28 questions

Explain INNER, LEFT, RIGHT and FULL JOIN.SQL#joinJunior
How does the SELECT statement work?SQL#queryJunior
How do you filter rows with WHERE?SQL#queryJunior
What are aggregate functions (COUNT, SUM, AVG, etc.)?SQL#queryJunior
How do GROUP BY and HAVING work?SQL#queryJunior
How do ORDER BY and LIMIT work, and how do you paginate?SQL#queryJunior
How do INSERT, UPDATE and DELETE work?SQL#queryJunior
How do you handle duplicates with DISTINCT?SQL#queryJunior
What are subqueries and how do you use them?SQL#queryMiddle
What are UNION, INTERSECT and EXCEPT?SQL#queryMiddle
How does the CASE expression work?SQL#queryMiddle
What are common string and date functions?SQL#queryMiddle
What is a self-join?SQL#queryMiddle
What are window functions?SQL#querySenior
What are Common Table Expressions (CTEs)?SQL#querySenior
What is UPSERT (INSERT ON CONFLICT)?PostgreSQL#queryJunior
What does the RETURNING clause do?PostgreSQL#queryJunior
How do CTEs and recursive queries work in PostgreSQL?PostgreSQL#queryMiddle
How do CRUD operations work in MongoDB?MongoDB#queryJunior
What query operators does MongoDB provide?MongoDB#queryJunior
How do find queries and projections work?MongoDB#queryJunior
How do you insert, update and delete documents?MongoDB#queryJunior
How do sorting and pagination work in MongoDB?MongoDB#queryJunior
How do you combine conditions with logical operators?MongoDB#queryJunior
What is the aggregation pipeline?MongoDB#queryMiddle
What update operators does MongoDB provide?MongoDB#queryMiddle
What advanced aggregation features does MongoDB offer?MongoDB#querySenior
How do geospatial queries work in MongoDB?MongoDB#queryMiddle