SQL JOIN USING – A Beginner’s Guide
Introduction In this article, we are going to see how the JOIN USING clause works in SQL, and how we can use it to replace the ON condition clause when the columns used to join the two tables have the same name in both the parent and the child tables.
SQL LEFT JOIN – A Beginner’s Guide
Introduction In this article, we are going to see how LEFT JOIN works in SQL, and how we can use it to associate rows belonging to different tables and build compound result sets. Unlike JOIN or INNER JOIN, LEFT JOIN is an OUTER JOIN. So, LEFT JOIN and LEFT OUTER JOIN are equivalent. Other OUTER JOIN types are RIGHT OUTER JOIN and FULL OUTER JOIN. However, since the SQL OUTER keyword is superfluous, it’s usually omitted.