What is a View in SQL

A View is a virtual table created from one or more existing database tables using a SQL query.

Unlike a real table, a View does not store data physically. It stores only the SQL query. Whenever you access the View, SQL fetches the latest data from the original table(s).

Simple Definition

A View is a virtual table that displays data from one or more tables.

Hindi Explanation

View एक Virtual Table होती है। इसमें वास्तविक (Physical) Data Store नहीं होता। इसमें केवल SQL Query Store होती है। जब भी View को Access किया जाता है, यह Original Table से नया (Latest) Data दिखाती है।

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Why Do We Need Views?

Suppose an Employee table contains confidential information.

Employee Table

EmployeeID	EmployeeName	Department	Salary	Phone
101	Rahul	IT	50000	9876543210
102	Aman	HR	40000	9876543211
103	Neha	IT	60000	9876543212

HR employees should not see the Salary and Phone columns.

Instead of creating another table, we create a View.

The View only displays:

• Employee Name
• Department

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How a View Works

              Employee Table
                     │
         ┌───────────┴───────────┐
         │                       │
     SQL VIEW               SQL Query
         │                       │
         └───────────┬───────────┘
                     │
             Virtual Table

A View acts as a window to the original table.

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Syntax

Create a View

CREATE VIEW ViewName AS
SELECT column1, column2
FROM TableName;

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Example 1: Create a View

Employee Table

EmployeeID	EmployeeName	Department	Salary
101	Rahul	IT	50000
102	Aman	HR	40000
103	Neha	IT	60000

Create a View:

CREATE VIEW Employee_View AS
SELECT EmployeeName,
Department
FROM Employee;

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Display the View

SELECT *
FROM Employee_View;

Output

EmployeeName	Department
Rahul	IT
Aman	HR
Neha	IT

Only selected columns are displayed.

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Example 2: View with WHERE Clause

Create a View showing only IT employees.

CREATE VIEW IT_Employees AS
SELECT EmployeeName,
Salary
FROM Employee
WHERE Department='IT';

Display the View.

SELECT *
FROM IT_Employees;

Output

Employee	Salary
Rahul	50000
Neha	60000

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Example 3: View Using Multiple Tables

Customer Table

CustomerID	CustomerName
101	Rahul
102	Aman

Orders Table

OrderID	CustomerID	Product
1	101	Laptop
2	102	Mobile

Create a View.

CREATE VIEW Customer_Order_View AS
SELECT
Customer.CustomerName,
Orders.Product
FROM Customer
INNER JOIN Orders
ON Customer.CustomerID =
Orders.CustomerID;

Display the View.

SELECT *
FROM Customer_Order_View;

Output

Customer	Product
Rahul	Laptop
Aman	Mobile

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Updating a View

Some Views are updatable.

UPDATE Employee_View
SET Department='Sales'
WHERE EmployeeName='Rahul';

The original table is updated automatically.

Note: Views that use GROUP BY, DISTINCT, aggregate functions, or complex joins are often not updatable.

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Replacing a View

Modify an existing View.

CREATE OR REPLACE VIEW Employee_View AS
SELECT
EmployeeName,
Department,
Salary
FROM Employee;

This replaces the old View with a new definition.

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Dropping a View

Delete a View.

DROP VIEW Employee_View;

Only the View is deleted.

The original table remains unchanged.

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View vs Table

Feature	View	Table
Stores Data	❌ No	✅ Yes
Physical Storage	❌ No	✅ Yes
Created From	SQL Query	User Data
Can Join Tables	✅ Yes	❌ No
Shows Latest Data	✅ Yes	✅ Yes
Security	High	Normal