A view in a database is a virtual table based on the result set of a SELECT statement. Views do not store data themselves, but rather display data from the underlying tables based on a set of defined criteria. Views can be used for a variety of purposes, such as:

1. Simplifying complex queries: Views can be used to simplify complex queries by providing a simpler interface for users to interact with.
2. Data security: Views can be used to control user access to sensitive data by limiting the columns or rows that are displayed.
3. Data abstraction: Views can be used to abstract the underlying data model, providing a simpler, more intuitive view of the data for end users.
4. Data integration: Views can be used to integrate data from multiple tables or even multiple databases into a single view, making it easier to analyze data from different sources.

Overall, views can be a powerful tool for managing data and providing a simpler, more intuitive interface for users to interact with.

For example

Let's say you have a table called sales_data with columns sales_id, date, product, and amount. You can create a view called monthly_sales that shows the total sales amount for each month:

CREATE VIEW monthly_sales AS
SELECT DATE_TRUNC('month', date) AS month,
       SUM(amount) AS total_sales
FROM sales_data
GROUP BY month;

You can then query this view to get the monthly sales data:

SELECT * FROM monthly_sales;

This will give you a result set with the total sales for each month. The benefit of using a view in this case is that you don't have to write the same SQL query every time you need to get the monthly sales data. You can simply query the monthly_sales view instead. Additionally, if the underlying data in the sales_data table changes, the view will automatically reflect those changes without having to rewrite the query.