Drupal's default sorting isn't very useful. We showed how to set up single-level and multilevel sorting, then added exposed sorts. Using an exposed sort gives visitors flexibility in how they view the content not contained in tables, which can use the built-in sortable columns options. From order, we covered filtering. Filtering lets a View builder control what information should be displayed, selecting a subset of the query-generated extracts from the database. For those who know SQL, this is the WHERE clause in most SQL queries. Exposed filters again give the visitor more control of how and what is displayed—in our example, limiting property listings by size (bedrooms), cost, and/or neighborhood.

In the next chapter, we'll extend the exposed filter concept to the ways by which Drupal sites can pass the filter criteria via the URL as well as use information from the page being displayed to control the information displayed in a block. These are called contextual...