Every JOIN side by side

The same two tables, joined every way. Dev has never borrowed a book, and loan 5 belongs to a member whose record was deleted, so each join keeps a different set of rows. Pick a card to see it below.

• JOIN (INNER) Only the rows that match in both tables. Each loan with its member, when unmatched rows don't matter.
• LEFT JOIN Every row of the first table (after FROM), matched or not. Every member, with their loans if they have any. Like a lookup that keeps your whole list.
• RIGHT JOIN Every row of the second table (after JOIN), matched or not. Rarely written: swap the tables and use LEFT JOIN instead.
• FULL JOIN Every row of both tables, matched or not. Comparing two lists to see everything: matches, and what each side has that the other doesn't.
• LEFT only Rows of the first table with no match. What's missing: members who never borrowed, products never sold.
• RIGHT only Rows of the second table with no match. Orphans: loans whose member has been deleted. Usually written as a LEFT JOIN from loans.

SELECT members.name, loans.loan_date
FROM members JOIN loans
  ON members.member_id = loans.member_id;