What is the purpose of using composite indexes in databases?

Composite indexes in databases are created on multiple columns simultaneously. Their purpose is to speed up queries that filter or sort data based on several fields.

Advantages of composite indexes:

• Improve the performance of complex queries with multiple conditions.
• Allow efficient use of the index if queries frequently use a combination of these fields.

For example, if you have an orders table with fields user_id and order_date, and queries are often performed on both fields, then a composite index (user_id, order_date) will allow quick retrieval of the needed records.

It is important to remember that the order of columns in a composite index affects its efficiency: the index is useful for queries starting with the first column of the index.