Filter and show database value based on user selection

If you want to filter posts and want to avoid custom coding, try out a few of the filtering plugins.

Depending on what sort of data you are filtering, you may not need custom coding. You would only need to properly name the form fields so they become the correct URL query vars to return the desired content. Let’s say you wanted to make a form that lets users select what category they want to view. If you name the form field “category_name” and have its selection values be identical to category slug names, a GET method URL might look like https://example.com/?category_name=foo. Assuming the user selected the “Foo” option.

If you have somewhat complex filtering needs, you probably are looking at some custom coding. The form data would need to be translated into appropriate query vars that WP will use to get the desired posts. The code to process the form data and make the query and display results could all reside on a custom page template.

I’m sorry, I am unable to help you in real time. I recognize asynchronous communication through this forum is very slow and tedious, but it’s the only form of assistance I personally offer. There is a WP chat channel over IRC. I don’t participate there, but if someone knowledgeable happens to be online at the time it can be a good way to have your questions answered in short order.

While the format isn’t much different, you might get faster responses at wordpress.stackexchange.com. There seems to be more participants in general over there. Alternately, you could hire an expert from sites like https://jobs.wordpress.net/ or https://jetpack.pro/ to help you for 10 minutes or so.

Or if you have enough patience, continue asking questions here.