Sitecore Solr Search Result Items Relevance Percentage

In a latest project I worked on there was a requirement on site search that a percent value should be displayed for each result item describe how much accurate it is for the current search criteria ( filters ), Or in another words we want to sort the returned result items starting with the closet item to search filters at the top.

Sitecore solr search boosting

In this blog I will explain a useful functionality in sitecore solr search that it used when you want to sort search result item based in clauses ( predicates ) matching.