inner join calendar on calendar.id = calendarusers.calendarid --I'm not sure what you need this table for, but it's there ...

The first part of the MySQL statement identifies the columns from the first table, and the "INNER JOIN" command combines it with the columns from the second table.

Fastest Way to Check if MYSQL Table Exists in PHP. Dynamic PHP pages give you the option to choose a MySQL table dynamically from which to query.