What is an index in SQL and how does it work?

An index in SQL is a database object that improves the speed of data retrieval operations

on a table. It works by maintaining a sorted order of column values in a separate structure,

allowing for faster search and retrieval compared to scanning every row in the table. The

index essentially creates a quick lookup table to find specific values.

Example of an index creation:

CREATE INDEX idx_column_name ON table_name(column_name);

Indexes are particularly useful for queries that involve WHERE, JOIN, ORDER BY, and GROUP

BY clauses.