SQL Server uses binary tree with intermediate and leaf node for search but how it will do this. Ex. If a table employee has two fields
Id bigint
Name varchar(5
How It Works
The database takes the columns specified in a CREATE INDEX command and sorts the values into a special data structure known as a B-tree. A B-tree structure supports fast searches with a minimum amount of disk reads, allowing the database engine to quickly find the starting and stopping points for the query we are using.
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This question is a conceptual one and requires a very straight forward answer You can read this article for a short answer :
How Does an SQL Index work