$criteria = new Criteria(); $criteria->addSelectColumn(‘column1’); $criteria->addSelectColumn(‘column2’); $criteria->addJoinMC(‘table1.column’, ‘table2.column’, ‘table3.column’);In this example, the addSelectColumn method is used to specify the columns to be selected in the query, and addJoinMC method is used to join the columns of 3 different tables with each other. The PHP Criteria class is part of the Propel package/library, which is an Object-Relational Mapping (ORM) library that allows developers to interact with databases using PHP objects.