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Course 2

Databases & SQL

“Almost every app stores data. Learn to query it with SQL, a skill that shows up in nearly every junior job description.”

Lessons

Start the course →0 of 10 lessons done
  1. Tables & SELECT QueriesRead data with SELECT, filter it with WHERE and sort it with ORDER BY. · 12 min
  2. Filtering Rows with WHEREAND, OR, IN, BETWEEN, LIKE and NULL. Ask exactly the question you mean. · 9 min
  3. Sorting, Limiting & DISTINCTOrder results, take the top N, and remove duplicates. · 7 min
  4. Counting & Summarizing (Aggregates)COUNT, SUM, AVG, MIN and MAX turn many rows into one answer. · 8 min
  5. Grouping Results with GROUP BYOne summary row per category, the query behind every dashboard. · 9 min
  6. Combining Tables with JOINSee exactly how INNER and LEFT JOIN match rows, then write your own. · 10 min
  7. JOINs & GROUP BYCombine tables and summarize data, the queries interviewers ask most often. · 15 min
  8. INSERT, UPDATE & DELETEAdd, change and remove data safely, and why WHERE is your seatbelt. · 9 min
  9. Designing & Creating TablesPick columns, types and keys that keep your data correct. · 10 min
  10. Subqueries & CTEsUse the answer of one query inside another, and keep complex queries readable. · 9 min
  1. Indexes: why queries get slowComing soon ✏️
  2. Window functions (ROW_NUMBER, RANK)Coming soon ✏️
  3. Using a database from your codeComing soon ✏️