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Data Analytics · Module 4 of 10

SQL for analysts

Query databases to answer business questions.

📖 Key ideas

  1. SELECT columns FROM table WHERE conditions.
  2. GROUP BY with COUNT, SUM, AVG for summaries.
  3. JOIN tables: customers with orders.
  4. ORDER BY and LIMIT for top-N lists.
  5. CTEs (WITH) make complex queries readable.
💡 Real-life example: SQL is asking a librarian precise questions instead of reading every book yourself.
SELECTChooses columns
GROUP BYGroups rows for aggregates
JOINCombines tables
CTENamed temporary result with WITH