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What Are Views in SQL? Advantages and Use Cases

Writer's picture: IOTA ACADEMYIOTA ACADEMY

In today's data-driven environment, effective data management and querying are essential. One of the most effective methods for doing this is SQL views. In SQL, a view is a virtual table that shows the outcome of a query. It offers a reusable layer for data analysis and reporting, improves data security, and streamlines complicated queries. We'll go into great detail about SQL views in this blog, including its benefits and real-world applications with examples.


SQL

What Are Views in SQL?


A view is essentially a saved query that behaves like a table. Views offer a dynamic snapshot of the data in the underlying tables rather than storing it like physical tables do. This prevents data duplication and lets you access and work with the data as though it were in a table.


Think of a view as a window into your database, designed to display only specific columns, rows, or calculations. You can learn more about SQL views from SQLServerTutorial.net.


A view can be thought of as a window into your database. A view is a powerful abstraction layer over raw data because it may be designed to display only particular columns, rows, or calculations.


Syntax for Creating a View

CREATE VIEW view_name AS

SELECT column1, column2, ...

FROM table_name

WHERE condition;

Once created, the view can be queried like a regular table:

SELECT * FROM view_name;

Find detailed examples of creating views on MySQLTutorial.


Advantages of Views


1.  Simplification of Complex Queries


By combining complex queries into a single, reusable item, views make them easier to understand. You can make a view and refer to it as a table rather than recreating a long query with numerous joins or computations.


For more insights, check out GeeksForGeeks: SQL Views.


Example:


Let's say you regularly create reports by joining the Orders, Customers, and Products tables. Making a view for this query makes it easier to use in the future:

CREATE VIEW CustomerOrders AS

SELECT o.OrderID, c.CustomerName, p.ProductName, o.Quantity

FROM Orders o

JOIN Customers c ON o.CustomerID = c.CustomerID

JOIN Products p ON o.ProductID = p.ProductID;

Now, fetching customer orders becomes as simple as:

SELECT * FROM CustomerOrders;


2.  Enhanced Data Security


Views restrict access to sensitive information by exposing only specific columns or rows. Users accessing a view cannot see the underlying tables, ensuring data privacy and security.


Learn more about enhancing data security with views at Stack Overflow.


Example:


If a table contains sensitive employee details like salaries, a view can expose only non-sensitive columns:


CREATE VIEW PublicEmployeeData AS

SELECT EmployeeID, EmployeeName, Department

FROM Employees;


Users accessing PublicEmployeeData will see only these columns, not salary data.


3.  Reusability


You can reuse a query in several reports, analytics, and apps by designating it as a view. This lessens query logic duplication and encourages consistency.


Find additional details at Medium: Getting Started with SQL Views.


4.  Data Abstraction


Views shield users from the intricacy of the database schema. It is possible to update the view without impacting dependent queries or applications in the event that the schema of the underlying tables changes.


Learn about data abstraction in SQL on Oracle Documentation.


5.  Improved Performance with Materialized Views


Materialized views are used in certain database systems (like Oracle and PostgreSQL) to physically store query results, which enhances performance for data that is requested frequently.


Explore materialized views in PostgreSQL Documentation.


Use Cases for SQL Views


Use Case 1: Filtering Data


Views are ideal for displaying subsets of data based on specific criteria. For example, creating a view to show only high-value sales:


CREATE VIEW HighValueSales AS

SELECT SalesID, CustomerID, Product, Quantity, (Quantity * Price) AS TotalValue

FROM Sales

WHERE (Quantity * Price) > 1000;

This view makes it easy to query high-value transactions:

SELECT * FROM HighValueSales;


Use Case 2: Joining Multiple Tables


When working with normalized databases, views simplify the process of joining tables. For instance, combining Orders and Customers tables:

CREATE VIEW CustomerOrders AS

SELECT o.OrderID, c.CustomerName, o.OrderDate

FROM Orders o

JOIN Customers c ON o.CustomerID = c.CustomerID;

Use Case 3: Summarized Reporting


Views can summarize data for reporting purposes, such as calculating total sales by region:

CREATE VIEW SalesSummary AS

SELECT Region, SUM(TotalSales) AS TotalSalesByRegion

FROM Sales

GROUP BY Region;

Use Case 4: Hiding Complexity


Views simplify queries for end-users by hiding underlying complexity. For example, if you frequently calculate the profit margin:

CREATE VIEW ProfitMargins AS

SELECT ProductName, (Revenue - Cost) AS Profit

FROM Products;

Use Case 5: Consistency Across Queries


By using views, you can ensure consistent results for frequently accessed data. For example, a view for active customers can guarantee consistent filtering criteria:

CREATE VIEW ActiveCustomers AS

SELECT CustomerID, CustomerName

FROM Customers

WHERE IsActive = 1;

Example: Working with a View


Scenario: Managing Sales Data


Suppose you have the following Sales table:

SalesID

CustomerID

Product

Quantity

Price

Date

1

101

Laptop

2

1000

2023-01-10

2

102

Tablet

5

300

2023-01-11

3

103

Smartphone

1

800

2023-01-12

Creating a View


Let’s create a view to calculate and filter sales where the total value exceeds $1,000:

CREATE VIEW HighValueSales AS

SELECT SalesID, CustomerID, Product, Quantity, (Quantity * Price) AS TotalValue

FROM Sales

WHERE (Quantity * Price) > 1000;

Querying the View

SELECT * FROM HighValueSales;

Result:

SalesID

CustomerID

Product

Quantity

TotalValue

1

101

Laptop

2

2000


Maintaining and Dropping Views


  • To update a view:

CREATE OR REPLACE VIEW view_name AS

SELECT ...;

  • To delete a view:

DROP VIEW view_name;

Conclusion


By using views, developers and organizations can conceal complexity, encourage consistency, and boost speed in their database applications. SQL views are essential for streamlining data administration, improving security, and facilitating effective analysis.


Call to Action


Do you wish to become proficient in SQL and other crucial data analysis tools? Enroll in our Data Analysis Course now to improve your skills by learning how to efficiently design and use SQL views. Get started on the path to becoming an expert in data right now!

 

 


 


 

 

 

 

 

 

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