What are SQL joins and how do they work?

What are SQL joins and how do they work?

SQL joins are used to combine rows from two or more tables based on a related column. There are different types of joins like INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

Can you explain the difference between INNER JOIN and LEFT JOIN?

Sure! An INNER JOIN returns only the rows that have matching values in both tables, while a LEFT JOIN returns all rows from the left table and the matched rows from the right table. If there's no match, NULL values are returned for columns from the right table.

What is a use case for using a FULL OUTER JOIN?

A FULL OUTER JOIN is useful when you want to retrieve all records from both tables, regardless of whether there is a match. For example, if you want to see all customers and their orders, including customers without orders and orders without customers.

Can you give me an example SQL query using INNER JOIN?

Certainly! Here's an example: SELECT customers.name, orders.amount FROM customers INNER JOIN orders ON customers.id = orders.customer_id; This query retrieves the names of customers along with their order amounts.