In a previous article we talked about the various type of
JOIN we can use in a MariaDB/MySQL database. This time, instead, we take a look at the
UNION statement: how it works, how we can use it to combine the result of queries run on different tables, and what are its peculiarities.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-combine-the-results-of-multiple-sql-queries-using-the-union-statement