🚀 SQL Roadmap 2026 — Part 17

SQL Views — Creating Reusable Virtual Tables

A SQL View is a saved SQL query that behaves like a virtual table.

Instead of writing the same complex query repeatedly, you can create a View once and query it like a table.

This is especially useful in:

• Data analytics

• Reporting

• Business Intelligence

• Power BI datasets

• Data warehouses

• Reusable business logic

• Data security

1️⃣ What Is a View?

Suppose you frequently need this query:

SELECT
    customer_id,
    customer_name,
    country,
    total_sales
FROM customers
WHERE country = 'India'
  AND total_sales > 100000;

Instead of writing it every time, you can create a View:

CREATE VIEW high_value_indian_customers AS
SELECT
    customer_id,
    customer_name,
    country,
    total_sales
FROM customers
WHERE country = 'India'
  AND total_sales > 100000;

Now you can simply write:

SELECT *
FROM high_value_indian_customers;

The View behaves like a table from the user's perspective.

2️⃣ Why Do We Need Views?

Imagine your reporting query contains:

• 4 JOINs

• 3 CASE statements

• Multiple filters

• Several calculated columns

• Aggregations

You don't want every analyst or report to rewrite that logic.

A View allows you to centralize the logic.

3️⃣ Basic CREATE VIEW Syntax

The general syntax is:

CREATE VIEW view_name AS
SELECT
    column1,
    column2,
    column3
FROM table_name
WHERE condition;

Example:

CREATE VIEW active_customers AS
SELECT
    customer_id,
    customer_name,
    country
FROM customers
WHERE status = 'Active';

Query the View:

SELECT *
FROM active_customers;

4️⃣ A View Can Contain JOINs

Views aren't limited to simple SELECT statements.

For example:

CREATE VIEW customer_orders AS
SELECT
    c.customer_id,
    c.customer_name,
    o.order_id,
    o.order_date,
    o.order_amount
FROM customers c
JOIN orders o
    ON c.customer_id = o.customer_id;

Now:

SELECT *
FROM customer_orders;

returns the result of that JOIN.

You don't need to repeatedly write the JOIN.

5️⃣ Views with Aggregation

You can also create aggregated Views.

Suppose management regularly needs regional sales:

CREATE VIEW regional_sales AS
SELECT
    region,
    SUM(order_amount) AS total_sales,
    COUNT(*) AS total_orders
FROM orders
GROUP BY region;

Now:

SELECT *
FROM regional_sales;

Example result:

region     total_sales     total_orders
North      450000          1250
South      620000          1580
West       510000          1390
East       380000          980

You can further analyze the View:

SELECT *
FROM regional_sales
WHERE total_sales > 500000;

6️⃣ Views with CASE Statements

Views are useful for standardizing business logic.

For example:

CREATE VIEW customer_segments AS
SELECT
    customer_id,
    customer_name,
    total_sales,
    CASE
        WHEN total_sales >= 100000 THEN 'High Value'
        WHEN total_sales >= 50000 THEN 'Medium Value'
        ELSE 'Low Value'
    END AS customer_segment
FROM customers;

Now every report can use the same segmentation logic:

SELECT
    customer_segment,
    COUNT(*) AS customers
FROM customer_segments
GROUP BY customer_segment;