Defining Your Database – SQL Data Definition Language (DDL) Basics
Learn how to create, modify, and manage your database structures using SQL’s Data Definition Language (DDL). SQL DDL Components SQL Data Definition Language (DDL) Components CREATE TABLE Define new tables INDEX Improve query performance VIEW Virtual tables CREATE TABLE employees ( id INT PRIMARY KEY, name VARCHAR(100), department VARCHAR(50), salary DECIMAL(10,2) ); ❌ No Table […]
Data Manipulation in SQL – INSERT, UPDATE, and DELETE Essentials
Learn how to modify your data using SQL’s core Data Manipulation Language (DML) commands: INSERT, UPDATE, and DELETE. SQL Data Manipulation Operations SQL Data Manipulation Operations INSERT INSERT INTO employees (id, name, department, salary) VALUES (4, ‘Alice’, ‘Marketing’, 65000); id name department salary 1 John IT 75000 2 Sarah HR 65000 3 Mike Sales 70000 […]
Demystifying SQL Functions – Aggregate, Scalar, and Window Functions
Unlock the power of SQL by mastering its functions. Learn how aggregate, scalar, and window functions can transform your data analysis. SQL Functions Comparison SQL Functions Comparison Aggregate Functions Example: SUM, COUNT, AVG – Combines multiple rows – Returns single value – Used with GROUP BY Scalar Functions Example: UPPER, LOWER, LENGTH – Operates row […]
Using Subqueries in SQL – A Guide to Nested Queries
Learn how to leverage subqueries to perform complex data retrieval in SQL by embedding one query within another. Nested Query Structure SELECT customer_name, total_orders FROM customers WHERE total_orders > ( SELECT AVG(total_orders) FROM customers WHERE region = ‘North’ ); Outer Query Inner Query (Subquery) Executes First Returns Single Value How it works: Inner query executes […]
Mastering SQL Joins – INNER, LEFT, RIGHT, and FULL OUTER Explained
Learn how to combine data from multiple tables using SQL Joins. Discover the differences between INNER, LEFT, RIGHT, and FULL OUTER joins and when to use each. SQL JOIN Types – Visual Guide SQL JOIN Types Visualization INNER JOIN Returns only the matching records from both tables where the join condition is met. LEFT JOIN […]
Grouping Data in SQL – Using GROUP BY and HAVING
Learn how to aggregate and summarize your data using the GROUP BY clause, and refine your groups with the HAVING clause in SQL. Introduction When working with large datasets, simply retrieving individual rows is often not enough. You need to summarize and analyze your data by grouping similar records together. In SQL, the GROUP BY […]
Sorting Data with ORDER BY – Organize Your Results
Learn how to effectively organize your query results using the ORDER BY clause in SQL. Introduction Once you’ve learned how to select and filter data using the SELECT statement and the WHERE clause, the next step is to present your data in a logical order. The ORDER BY clause is your tool for arranging query […]
How to Write a Basic SQL SELECT Statement
Learn the foundation of SQL querying with a clear, step-by-step guide on writing a basic SELECT statement. Introduction The SELECT statement is the backbone of SQL queries. It allows you to retrieve specific data from one or more tables, making it an essential tool for anyone working with databases. In this article, you’ll learn: If […]
Filtering Data in SQL – Mastering the WHERE Clause
Learn how to refine your SQL queries with the powerful WHERE clause and get exactly the data you need. Introduction When working with databases, retrieving data quickly is only half the battle—you also need to extract the precise subset of data that matters. This is where the WHERE clause comes in. In this guide, we’ll […]
SQL 101: What Is SQL and Why It Matters
Learn the fundamentals of Structured Query Language (SQL) and discover why it’s the backbone of modern data management. Introduction Have you ever wondered how vast amounts of data—from customer records to sales figures—are stored, managed, and made meaningful? The answer lies in SQL. Whether you’re completely new to databases or looking to refresh your knowledge, […]
