Press "Enter" to skip to content

Fun with Natural Full Join

Lukas Eder shows off natural joins:

At first I though of the UNION CORRESPONDING syntax, which doesn’t really exist in most SQL dialects, even if it’s a standard feature. But then, I remembered that this is again a perfect use case for NATURAL FULL JOIN, this time slightly differently from the above example where two tables are compared for contents. This time, we want to make sure the two joined tables never have matching rows, in order to get the UNION like behaviour.

I wasn’t aware of the notion of natural joins because they’re not available in SQL Server. They are available in Oracle, Postgres, and MySQL. Fun as Lukas’s blog post is, I could see natural joins going wrong in so many ways.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.