Difference between full-text search and exact match

In this section, we will describe analyzers and why they are necessary for text search. Let's say we have a document containing the following information:

{
   "date": "2017/02/01",
   "desc": "It will be raining in yosemite this weekend"
 }

If we want to search for the documents that contain word yosemite, we could run an SQL query as shown here:

select * from news where desc like '%yosemite%'

This functionality is very limited and is never sufficient for real-world text-search queries. For example, if a user is looking for the weather forecast in Yosemite, he/she would query for the same in human language using something such as rain in yosemite. Since SQL can only match the exact words, and the document doesn't contain the word rain, the query will not come back with any results.

Elasticsearch is a full-text search engine and is built to handle these kinds of queries. Before the documents are indexed into Elasticsearch, the fields in the...