Day 7 of 14 35 minINNERLEFTFULLSelf join
Combine rows from related tables. Match books with their authors using INNER JOIN, keep unmatched rows with LEFT and FULL JOIN, and chain joins across several tables.
By the end of today you can
- Combine two tables with INNER JOIN … ON
- Keep unmatched rows with LEFT JOIN and FULL JOIN
- Find rows with no match using LEFT JOIN … WHERE … IS NULL
- Join three or more tables in one query
- Use table aliases to keep queries readable
What's inside
- 5 sections
- 3 diagrams and mind maps
- 5 code examples you can run
- 4-question quiz
- 1INNER JOIN: matching pairs
- 2LEFT JOIN: keep every row on the left
- 3Finding rows with no match
- 4FULL JOIN: everything from both sides
- 5Joining three or more tables
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