How to embed query results into wordpress page?

I'm not exactly sure how to ask this question or explain it. We are looking to have information found in a non-wordpress multi-site MySQL database tables displayed on a wordpress multi-site page. We would like to make this information available when someone selects the option from a public web interface which is embedded in WordPress Multi-Site.

For example, we would like someone to "Select an Option" from a drop down list or select a link, and then this would trigger the query, and displaying the results of their selection dynamically in a new web page.

Is there a Plugin or Tool for doing this safely? Would this require custom development from a developer?