A Practical Introduction to SQL Views and Materialized Views

SQL views let you simplify how data is accessed and presented. Instead of repeating joins and filters, you define the logic once and then use it like a table, which is ideal for keeping your queries DRY and consistent.

Why use SQL views?

Views are useful when:

• You want to reuse the same joins or filters.

• Users need restricted access to certain columns.

• You’re building reports and want consistent outputs.

• You need to simplify the query layer of your app.

Using views in SQL

Here’s how views work in practice:

Define a view:

CREATE VIEW EmployeeManagers AS
SELECT emp.employee_name, mng.employee_name
FROM Employees emp
JOIN Employees mng ON emp.manager_id = mng.employee_id;

Query it:

SELECT * FROM EmployeeManagers;

Drop it when no longer needed:

DROP VIEW EmployeeManagers;

The view reflects updated data from the base tables every time you run it.

Materialized Views at a Glance

Need speed over real-time data? Use a materialized view.

• Stores the result of a query.

• Great for reporting and read-heavy workloads.

• Requires manual or scheduled refresh.

• Not all databases support it, but PostgreSQL does.

FAQ

What’s a view?

A saved SQL query used like a table.

Is it different from a table?

Yes. Views don’t store data—they return live results.

How do I make one?

Use CREATE VIEW and define a SELECT query.

Can I update it?

Not directly, drop and recreate when needed.

Conclusion

SQL views help organize query logic, protect data, and reduce code repetition. Materialized views add performance when speed is needed. Read SQL Views: A Comprehensive Guide for more details and visual tools.