SQL & Databases

Section 1 · Reading data

• 1 What a database is SQL —
• 2 SELECT the basics SQL —
• 3 Choose columns SQL —
• 4 WHERE filters rows SQL —
• 5 Numbers in WHERE SQL —
• 6 AND, OR, NOT SQL —
• 7 ORDER BY sorts SQL —
• 8 Sort by two columns SQL —
• 9 LIMIT and OFFSET SQL —
• 10 COUNT rows SQL —

Section 2 · Summaries

• 11 SUM a column SQL —
• 12 AVG, MIN, MAX SQL —
• 13 ROUND the answer SQL —
• 14 GROUP BY SQL —
• 15 HAVING SQL —
• 16 Count distinct SQL —
• 17 Aliases SQL —
• 18 CASE WHEN SQL —
• 19 NULL and COALESCE SQL —
• 20 INNER JOIN SQL —

Section 3 · Joins and subqueries

• 21 JOIN three tables SQL —
• 22 LEFT JOIN keeps everyone SQL —
• 23 Find students who never paid SQL —
• 24 JOIN with a condition SQL —
• 25 Aggregate over a join SQL —
• 26 UNION SQL —
• 27 Subquery in WHERE SQL —
• 28 Subquery in FROM SQL —
• 29 String functions SQL —
• 30 LIKE pattern search SQL —

Section 4 · Changing data

• 31 Dates as text SQL —
• 32 INSERT a row SQL —
• 33 INSERT several rows SQL —
• 34 UPDATE one row SQL —
• 35 UPDATE with a calculation SQL —
• 36 DELETE a row SQL —
• 37 Transactions SQL —
• 38 CREATE TABLE SQL —
• 39 Primary keys SQL —
• 40 Foreign keys SQL —

Section 5 · Real academy queries

• 41 Views SQL —
• 42 Indexes SQL —
• 43 Monthly revenue SQL —
• 44 Collected vs expected SQL —
• 45 Students per course SQL —
• 46 Top paying student SQL —
• 47 Pagination query SQL —
• 48 Duplicate check SQL —
• 49 Safe UPDATE checklist SQL —
• 50 SQL injection SQL —

Capstone: reports a client would pay for

• 51 Keep the newest rows SQL —
• 52 Find groups above a threshold SQL —
• 53 Join students to their course SQL —
• 54 Filter with a subquery SQL —
• 55 Label rows with CASE SQL —
• 56 Count rows safely with LEFT JOIN SQL —

Final exam and certificate

Twenty questions from the whole track. Pass mark is 60%. Retakes are free and the best score is the one printed on your certificate.