Sphinx is a full-text search engine. So, before going any further, we need to understand what full-text search is and how it excels over the traditional searching.
Full-text search is one of the techniques for searching a document or database stored on a computer. While searching, the search engine goes through and examines all of the words stored in the document and tries to match the search query against those words. A complete examination of all the words (text) stored in the document is undertaken and hence it is called a full-text search.
Full-text search excels in searching large volumes of unstructured text quickly and effectively. It returns pages based on how well they match the user's query.