What is a Query Variable?
A query variable is a parameter that you add to the end of a query string. The parameter tells the query what information to return from the database.
More About Query Variables
Parameters are crucial for queries that you want to return specific results. For example, the default WordPress permalink structure includes a query that specifies precisely which post the URL should return.
Here’s what that looks like:
http://yourwebsite.com/?p=123
If you remove the “123” query variable or parameter, WordPress won’t know which content to pull from the database. The URL won’t work, and it will return an error.
The structure and naming conversions of query variables will change depending on what data you’re requesting from the database. Furthermore, the parameters might not always be visible in URLs because the requests often happen in the background when you load or interact with a website.
