In this blog, we will explore a wide range of technology topics including SQL, Snowflake, and Python. Whether you’re a beginner or looking to advance your skills, you’ll find step-by-step tutorials, real-world examples, and deep-dive explanations that help you master each subject. Our goal is to make learning easy, structured, and practical—from the basics to advanced levels.
SQL (Structured Query Language) is a programming language used to manage and interact with databases. It allows you to store, retrieve, update, and delete data.
Let’s take a store example (supermarket) and see how SQL is used in real-time:
A new customer buys items, so we record it in the database.
INSERT INTO Customers (CustomerID, Name, City)
VALUES (101, ‘Ravi Kumar’, ‘Hyderabad’);
–Adds Ravi as a new customer.
SELECTThe manager wants to see all customers from Hyderabad.
SELECT Name, City
FROM Customers
WHERE City = ‘Hyderabad’;
–Displays list of Hyderabad customers.
UPDATEA customer changes their phone number.
UPDATE Customers
SET Phone = ‘9876543210’
WHERE CustomerID = 101;
–Ravi’s phone number is updated.
DELETEA customer requests account deletion.
DELETE FROM Customers
WHERE CustomerID = 101;
–Removes Ravi’s record from the database.
In real-life apps (like Amazon, BigBasket, or a store’s billing system):
INSERT happens when a new order is placed.
SELECT is used when showing product listings or search results.
UPDATE occurs if stock quantity or customer details change.
DELETE happens if products are discontinued or accounts are closed.
REAL TIME EXAMPLE:
| CustomerID | Name | City | Phone |
|---|---|---|---|
| 101 | Ravi Kumar | Hyderabad | 9876543210 |
| 102 | Meena Rao | Chennai | 9123456789 |
| ProductID | ProductName | Price | Stock |
|---|---|---|---|
| 201 | Rice Bag | 800 | 20 |
| 202 | Sugar 1Kg | 50 | 100 |
| 203 | Milk 1L | 40 | 50 |
| OrderID | CustomerID | ProductID | Quantity | OrderDate |
|---|---|---|---|---|
| 301 | 101 | 202 | 2 | 2025-08-22 |
| 302 | 102 | 203 | 5 | 2025-08-22 |
Customer places an order for Rice Bag.
INSERT INTO Orders (OrderID, CustomerID, ProductID, Quantity, OrderDate)
VALUES (303, 101, 201, 1, ‘2025-08-22’);
Get all orders placed by Ravi.
SELECT o.OrderID, p.ProductName, o.Quantity, o.OrderDate
FROM Orders o
JOIN Products p ON o.ProductID = p.ProductID
WHERE o.CustomerID = 101;
Stock decreases after a purchase.
UPDATE Products
SET Stock = Stock – 1
WHERE ProductID = 201;
If an order is canceled.
DELETE FROM Orders
WHERE OrderID = 303;
1.Introduction to SQL
2. SQL Data Types
3. DataBase Operations
4. Table operations
5. SQL statements
6. Clauses and Conditions
7. SQL Operators
8. Keys and Constraints
9. Aggregate Functions
10. Joins
11. Other Concepts