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SQL Tutorial 6: Joins in SQL
Connect customers to orders with INNER and LEFT joins, using keys on purpose. Learn how join grain can explode row counts, when not to join, and how to…
SQL Tutorial 5: Aggregate Functions and Grouping Data
Turn rows into summaries with COUNT, SUM, AVG, MIN, and MAX. Group with GROUP BY, and learn when HAVING filters groups while WHERE filters rows, so your totals…
SQL Tutorial 4: Filtering and Sorting Data in SQL
Filter rows with WHERE, combine conditions with AND and OR, and use IN, BETWEEN, and careful LIKE patterns. Sort with ORDER BY and learn NULL basics so your…
SQL Tutorial 3: Retrieving Data with SELECT
Learn to retrieve exactly the columns you need with SELECT, rename them with aliases, remove duplicate rows with DISTINCT, and cap result size with LIMIT. Stop shipping SELECT…
SQL Tutorial 2: Master the Core Commands (SELECT, INSERT, UPDATE, DELETE)
Master the four core SQL commands: SELECT to read, INSERT to add, UPDATE to change, and DELETE to remove. Learn the safety habits that keep practice useful and…
