SQL JOINs

Combine data from multiple tables with INNER, LEFT, RIGHT joins

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Explanation

JOINs combine rows from multiple tables based on a related column.

sql

SELECT users.name, orders.total
FROM users
INNER JOIN orders ON users.id = orders.user_id;

Types:

INNER JOIN — only rows with matches in BOTH tables
LEFT JOIN — all rows from left table + matching from right (NULLs for no match)
RIGHT JOIN — all rows from right + matching from left
FULL OUTER JOIN — all rows from both tables

LEFT JOIN is the most commonly used because it keeps all records from your main table even when related data is missing.

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