Types of Views in SQL | Views in SQL [2025]

Ever wished you could save time by simplifying complex database tasks? That’s where SQL views come in, acting like a shortcut to the most relevant data. Views are virtual tables derived from query results that simplify complex queries and improve readability. They also enhance data security by restricting access, making database management more efficient. 

In this blog, you’ll explore the types of views in SQL, how they function, and how to use them effectively to simplify big data operations and manage data securely. 

Ready to dive in? 

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What Is a View in SQL?

Think of a view in SQL as a window into your database, showing only the data you need. This virtual table dynamically presents query results without storing them, simplifying complex datasets and offering a cleaner, user-friendly interface for analysis.

Formally, a view in SQL is a virtual table that encapsulates the results of a query. It presents data dynamically without physically storing it, making it a lightweight and efficient way to interact with complex datasets. By abstracting data from one or more tables, views simplify querying by providing users with a cleaner and more readable interface.

For example, instead of repeatedly writing a complex query to fetch sales data for the current year, you can create a view that does the work for you:

CREATE VIEW CurrentYearSales AS
SELECT OrderID, CustomerID, TotalAmount
FROM Sales
WHERE YEAR(OrderDate) = YEAR(GETDATE());

This view, CurrentYearSales, allows you to fetch the data directly with a simple SELECT * FROM CurrentYearSales, eliminating repetitive query writing.

Also Read: List of Operators In SQL [With Examples] 

Types of Views in SQL

SQL offers three primary types of views to address different data handling and query optimization needs:

• Simple Views: Derived from a single table, focusing on presenting specific columns or rows.
• Complex Views: Combine data from multiple tables or include operations like joins and aggregations.
• Materialized Views: Unlike the other two, materialized views store query results physically for faster access and performance.

Views come in different forms, each tailored to specific use cases. Let’s dive into the various types of views in SQL and see how they can simplify and enhance your database operations.

What Are Simple Views?

A simple view is derived from a single table, showcasing specific rows or columns based on defined criteria. These views are lightweight, easy to maintain, and ideal for primary use cases.

Critical aspects of the simple view are:

• Involves only one base table.
• Contains no joins, subqueries, or aggregate functions.

Characteristics

• Directly reflects changes made to the base table.
• Does not store data physically.
• Allows essential updates and queries.

It is best suited for use cases requiring minimal data abstraction and is ideal for presenting filtered or restricted table data views.

Have a look at the code example for the simple view:

-- Create a simple view to display active employees
CREATE VIEW ActiveEmployees AS
SELECT EmployeeID, FirstName, Department
FROM Employees
WHERE Status = 'Active';
-- Query the view
SELECT * FROM ActiveEmployees;

What Are Complex Views?

A complex view is built from multiple tables and often includes operations like joins, subqueries, or aggregate functions. These views are powerful for handling sophisticated queries.

The key aspects of the complex view are:

• Can combine data from multiple sources.
• Often includes advanced SQL features like grouping or aggregations.

Characteristics

• Reflects changes made to underlying tables.
• Suitable for reporting and analytical use cases.
• May include computed columns.

It supports advanced data modeling tasks and summarizes or analyzes large datasets.

Have a look at the code example for the complex view:

- Create a complex view to show total sales by department
CREATE VIEW DepartmentSales AS
SELECT d.DepartmentName, SUM(s.TotalAmount) AS TotalSales
FROM Departments d
JOIN Sales s ON d.DepartmentID = s.DepartmentID
GROUP BY d.DepartmentName;
-- Query the view
SELECT * FROM DepartmentSales;

What Are Materialized Views?

A materialized view physically stores query results in the database, eliminating the need to recalculate each time it’s accessed. This makes it a powerful tool for boosting performance and handling resource-intensive queries efficiently.

Critical aspects of the materialized view are:

• Stores query results as physical data.
• Requires periodic refreshes to update data.

Characteristics

• Occupies physical storage space in the database.
• Refresh methods can be on-demand or scheduled.
• Often used in OLAP (Online Analytical Processing) systems.

It is ideal for queries involving heavy aggregations or joins. It also reduces database workload by avoiding repetitive computations.

Have a look at the snippet for the materialized view: 
-- Create a materialized view to store aggregated sales data
CREATE MATERIALIZED VIEW SalesSummary AS
SELECT Region, SUM(TotalAmount) AS TotalSales
FROM Sales
GROUP BY Region;
-- Query the materialized view
SELECT * FROM SalesSummary;
-- Refresh the materialized view
REFRESH MATERIALIZED VIEW SalesSummary;

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Know the types of views? Next, let's get into working with Views.

How to Work With Views in SQL?

Working with views in SQL opens up a world of possibilities for efficient data management. Whether you’re optimizing queries, enhancing security, or organizing data for better readability, views are a powerful tool in your arsenal. Here’s how they can be applied effectively: 

• Simplify complex queries by abstracting data into virtual tables.
• Enhance data security by restricting access to sensitive columns or rows.
• Serve as reusable query templates for consistent data reporting.
• Aid in data analysis by aggregating or transforming data without altering the underlying tables.

Now that we understand views and their type, let’s dive into the practical side — how to create, use, modify, and manage views effectively in SQL.

How to Create a View in SQL?

Creating a view in SQL is your first step toward harnessing SQL's full potential. The CREATE VIEW command lets you define a virtual table based on a query, making repeated operations more efficient and readable.

Steps to Create a View:

• Use the CREATE VIEW statement followed by the view name.
• Write a SELECT query to define the data the view will present.

Let's understand this via code example: 

CREATE VIEW EmployeeDetails AS
SELECT EmployeeID, FirstName, LastName, Department
FROM Employees
WHERE Status = 'Active';

This view, EmployeeDetails, abstracts all active employees' information. You can query it directly:

SELECT * FROM EmployeeDetails;

How to Alter and Drop a View?

To modify an existing view, use the CREATE OR REPLACE VIEW command. This allows you to update the query logic without deleting the view.

Understand this via the below code:

CREATE OR REPLACE VIEW EmployeeDetails AS
SELECT EmployeeID, FirstName, LastName, Department, HireDate
FROM Employees
WHERE Status = 'Active';

To drop the view, use the DROP VIEW command to remove a view from the database if it’s no longer needed.

DROP VIEW EmployeeDetails;

Also Read: How to use ALTER Command in SQL

How to Use a View in SQL?

Once you’ve created a view, using it is as simple as querying a regular table. Let’s bring this to life with an example:

1. Fetch data:

SELECT * FROM EmployeeDetails WHERE Department = 'IT';

2. Join views with tables:

SELECT e.EmployeeID, e.FirstName, p.ProjectName
FROM EmployeeDetails e
JOIN Projects p ON e.EmployeeID = p.EmployeeID;

How to Update a View in SQL?

Under specific conditions, views can be updated directly, provided:

• The view references only one table.
• No aggregate functions or computed columns are used.

Check out the code snippet below for a clearer understanding:

UPDATE EmployeeDetails
SET Department = 'Finance'
WHERE EmployeeID = 101;

The underlying Employees table is automatically updated.

Inserting and Deleting Rows Into a View

You can insert or delete data through a view, provided it meets the criteria for updates.

1. First, have a look at how to insert rows:

INSERT INTO EmployeeDetails (EmployeeID, FirstName, LastName, Department)
VALUES (202, 'John', 'Doe', 'HR');

This adds the row to the base Employees table.

2. The below example deletes the rows:

DELETE FROM EmployeeDetails
WHERE EmployeeID = 202;

The record is removed from the underlying table.

How to Drop a View?

When a view is no longer needed, dropping it removes the abstraction layer. This does not impact the underlying tables. 

When to Use:

• When the view’s purpose is obsolete.
• To declutter the database from unused views.

DROP VIEW EmployeeDetails;

By understanding these commands and their applications, you can seamlessly integrate views into your SQL workflow, making your queries more efficient and secure.

Also Read: Stored Procedure in SQL: How to Create, Executive, Modify, Types & Use Cases

Now that you know how to work with views, let’s explore the key benefits they bring to your SQL workflows.

Benefits of Using Views

Imagine making your database tasks easier, more secure, and more efficient — views in SQL let you do just that. As you dive into their benefits, you'll see how they can transform the way you interact with your data.

Let’s explore them in brief.

1. Simplification

Views simplify complex queries by encapsulating them in reusable virtual tables. Instead of repeatedly writing long queries, you can use a view to retrieve data with a simple SELECT statement.

Why It Matters:

• Saves time and reduces errors by avoiding repetitive query writing.
• Makes queries more readable for both beginners and advanced users.

2. Security

Views provide an effective way to control data access. By exposing only specific columns or rows, views act as a protective layer over the underlying tables, keeping sensitive information secure.

Why It Matters:

• Limits user access to sensitive data like salaries or personal details.
• Prevents unauthorized modifications to the base tables.

3. Data Abstraction

Views allow you to present data in a format tailored to specific use cases, abstracting the complexity of underlying tables. This is especially useful for creating user-friendly datasets for non-technical stakeholders.

Why It Matters:

• Masks the complexity of joins, aggregations, and transformations.
• Presents data in a way that aligns with business needs.

4. Reusability

Once created, views can be reused across multiple queries, making them a valuable asset for repeated operations. This ensures consistency and saves time when working on similar tasks.

Why It Matters:

• Reduces redundancy by centralizing query logic.
• Ensures uniformity across different database operations.

5. Data Integrity

Views help maintain data integrity by presenting consistent data, regardless of how the base tables evolve. They also ensure that business rules or filters are consistently applied.

Why It Matters:

• Prevents accidental errors in data interpretation.
• Ensures consistent reporting and analysis.

Now that we’ve explored the benefits of using views, it’s crucial to understand how to implement them effectively. Let’s dive into some best practices to ensure you use views optimally in your SQL workflows.

Also Read: Top 10 Real-Time SQL Project Ideas: For Beginners & Advanced

Best Practice for Using Views

As a beginner, you might find views a bit overwhelming at first, with their virtual structure, query dependencies, and potential performance challenges. However, once you grasp the different types of views in SQL, you’ll gain a valuable tool to boost your database management skills and efficiency.  

Let’s dive into the key practice for using views.

Naming Conventions

Consistent naming conventions improve readability and collaboration when working with views. A transparent naming scheme helps developers understand the purpose of the view and its associated table.

Best practices:

• Use a prefix like vw_ to indicate a view, e.g., vw_ActiveEmployees.
• Include details about the data or purpose in the name, e.g., vw_SalesSummary.
• Avoid overly generic names like View1.

Have a look at the code snippet for how to use the proper naming:

-- Create a view with a clear, descriptive name
CREATE VIEW vw_EmployeeDetails AS
SELECT EmployeeID, FirstName, LastName, Department
FROM Employees
WHERE Status = 'Active';

This approach makes it clear that vw_EmployeeDetails provides information about active employees.

Performance Considerations

Based on their design, views can either improve or degrade performance. Simple views are lightweight, while complex or nested views can become slow if not optimized.

Performance tips:

• Avoid including unnecessary columns in the view.
• Limit the number of joins and aggregations.
• Use materialized views for computationally expensive queries.

Understand via the code example:

-- Optimized view with minimal columns and filters
CREATE VIEW vw_DepartmentSales AS
SELECT DepartmentID, SUM(TotalAmount) AS TotalSales
FROM Sales
WHERE SaleDate >= '2024-01-01'
GROUP BY DepartmentID;

This view limits data to recent sales and ensures faster query performance.

Security

Views are an excellent way to restrict access to sensitive data. Exposing only specific columns or rows allows you to control what information users can see without modifying the underlying table.

Security best tips:

• Grant access to the view instead of the base table.
• Use views to mask sensitive columns, like salaries or personal information.

Look at the code example to have a better understanding:

-- Create a secure view to restrict salary information
CREATE VIEW vw_PublicEmployeeData AS
SELECT EmployeeID, FirstName, LastName, Department
FROM Employees;
-- Grant access to the view, not the table
GRANT SELECT ON vw_PublicEmployeeData TO PublicUser;

Here, the PublicUser cannot access sensitive salary data in the Employees table.

Indexing

Indexing can improve the performance of queries that run against views, especially materialized ones. Indexed views (materialized views with indexes) speed up data retrieval for large datasets.

Best tips for indexing:

• Use indexed views for read-heavy operations.
• Ensure the indexed columns match the query’s filter conditions.

Have a look below for better indexing:

-- Create an indexed materialized view for faster lookups
CREATE MATERIALIZED VIEW mv_IndexedSales AS
SELECT Region, ProductID, SUM(SalesAmount) AS TotalSales
FROM Sales
GROUP BY Region, ProductID;
-- Add an index to the materialized view
CREATE INDEX idx_RegionProductSales ON mv_IndexedSales (Region, ProductID);

Indexed views are handy for reporting and analytics.

Also Read: Create Index in MySQL: MySQL Index Tutorial [2024]

Limit Nested Views

While creating views that depend on others is tempting, excessive nesting can lead to performance degradation and debugging difficulties. Instead, simplify your queries by reducing dependencies.

Best Practices:

• Avoid chaining views beyond two levels.
• Replace heavily nested views with a materialized view if necessary.

Go through the example below:

-- Nested views can slow down queries
CREATE VIEW vw_RegionSales AS
SELECT Region, SUM(SalesAmount) AS TotalSales
FROM Sales
GROUP BY Region;
CREATE VIEW vw_FilteredRegionSales AS
SELECT Region, TotalSales
FROM vw_RegionSales
WHERE TotalSales > 10000;
-- Better approach: combine into a single view
CREATE VIEW vw_OptimizedRegionSales AS
SELECT Region, SUM(SalesAmount) AS TotalSales
FROM Sales
WHERE SalesAmount > 10000
GROUP BY Region;

Reducing nested layers makes the query more efficient and easier to maintain.

By following these best practices, you can make the most of the types of views in SQL. These strategies enhance efficiency and elevate your skills as a database professional.

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