SQL Views

In this tutorial, we'll learn about views in SQL and how to use them with examples.

In SQL, views contain rows and columns similar to a table, however, views don't hold the actual data.

You can think of a view as a virtual table environment that's created from one or more tables so that it's easier to work with data.

How to use view in SQL
Example: SQL Views

Creating a View in SQL

We can create views in SQL by using the CREATE VIEW command. For example,

CREATE VIEW us_customers AS
SELECT customer_id, first_name
FROM Customers
WHERE Country = 'USA';

Here, a view named us_customers is created from the customers table.

Now to select the customers who lives in USA, we can simply run,

SELECT *
FROM us_customers;

Updating a View

It's possible to change or update an existing view using the CREATE OR REPLACE VIEW command. For example,

CREATE OR REPLACE VIEW us_customers AS
SELECT *
FROM Customers
WHERE Country = 'USA';

Here, the us_customers view is updated to show all the fields.


Deleting a View

We can delete views using the DROP VIEW command. For example,

DROP VIEW us_customers;

Here, the SQL command deletes the view named us_customers.

Note: If the view is not available, the above command throws an error.


Views for Complex Queries

Suppose A and B are two tables and we wan't to select data from both of the tables. For that, we have to use SQL JOINS.

However using the JOIN each time could be a tedious task. For that, we can create a view to fetch records easily.

Let's create a view,

CREATE VIEW order_details AS
SELECT Customers.customer_id, Customers.first_name, Orders.amount
FROM Customers
JOIN Orders
ON Customers.customer_id = Orders.customer_id;

Now, to select the data, we can run

SELECT *
FROM order_details;

Here, the SQL command selects data from the view order_details.

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