Introduction to SQL: What is SQL and What Is It Used For?

If you have been working with data at some point, you’ve probably come across the term SQL. SQL (or Structured Query Language) is a simple yet powerful programming language used to manage and manipulate data in databases. Whether you need to store customer-related data, track sales or inventory, store employee data, or analyze any kind of complex data, SQL is one of the most commonly used programming languages that makes working with large amounts of data quite easy.

What is SQL and What is it Used For?

In simple terms, SQL allows you to interact with relational databases—a type of database that organizes data into tables and can have relations between multiple tables. Each of these tables has rows and columns, similar to Excel spreadsheets. Each of the columns inside the table represents a specific piece of information (e.g. “Employee Name”, “Employee Birth Date” or “Employment Date”), and each of the table rows contains a unique entry defined by a unique identifier (e.g. “Employee ID”).

SQL gives you the ability to write queries and get the data from a table (or multiple tables) in a well-structured format.

For example, if you own a webshop, every order that your customers make will be stored in some kind of database. If you would like to know how many orders you had and how many items were sold in a specific period, you can write an SQL query and get the number of orders and items sold in a matter of seconds. Even if you had millions of such records inside the table, SQL can get them fast

Main Components of SQL

Let’s first say a few words about some key components of SQL:

• Databases: A database is a place that holds all of your data. In SQL, the database is a collection of organized information stored in tables.
• Tables: At the heart of a database are tables, which function like grids with rows and columns, similar to the ones in Excel. The columns define what kind of information is stored (e.g. names, dates and numbers), while rows contain the individual data entries (records).
• Queries: When you run a query on a database, you’re essentially asking it a question. With commands like SELECT, WHERE, and ORDER BY, you can filter and sort the data you’re searching for.
• Views: They act as “virtual tables” and are generated by queries. Views let you present complex data in a more straightforward way without changing the actual tables.
• Indexes: Just as a book index helps you efficiently find content, SQL indexes speed up data retrieval from large tables. You will notice that when running queries on large tables.
• Stored Procedures: Pre-written SQL commands like these can be stored and reused whenever you need to carry out repetitive tasks, such as updating data or creating monthly reports.

Understanding the main components of SQL will help you design better and more efficient databases, so you can get the data quickly.

Why do you need an SQL database?

You will use one or more SQL databases to store large amounts of structured data and to retrieve this data when needed. All kinds of businesses (small, enterprise, startups) rely on SQL databases to store their own data, or their customer’s data. Whether you’re managing employee records, tracking ordered items and quantities, or building reports to analyze trends, SQL databases can help you run your business smoothly.

Here are a few examples on how various industries use SQL databases:

• Webshops use SQL databases to store product-related information, inventory levels, and sales transactions.
• Hospitals and clinics use SQL to store patient records, appointments, and treatment histories.
• Banks, insurance companies, and other financial institutions use them to track account information, account balances, transactions, and client data.
• Social networks use SQL databases to store account data of their users

What is SQL Language Used For?

SQL is a versatile but fairly simple language that can be used in many different ways:

1. Querying (retrieving data): This is the most common way of using SQL language. By writing a simple SELECT statement, you can pull out a specific dataset, whether it’s all items you sold since the beginning of the year, or the top 10 customers by sales.
2. Data Manipulation: SQL also lets you insert, update, or delete data. You can use the statement INSERT INTO to add new records, UPDATE to modify it, or DELETE to remove records from a table.
3. Database Structure: SQL also allows you to change the structure of your database. Using a statement CREATE TABLE will create a brand new table inside the database, while using ALTER TABLE will modify the existing table.
4. Security and Permissions: One of the most important things you should do is to protect your data. Statements like GRANT and REVOKE can be used to control who has access to different tables inside the database.

Why Should You Use SQL?

Here are some of the main reasons why you should choose SQL:

1. Speed and Performance: SQL is simply fast! It is well-optimized to work with large datasets. It can handle complex queries efficiently, saving you time when pulling or updating data in your database.
2. Ease of Use: The logic is very clear, and the language is easy to learn. The syntax is straightforward and often sounds like natural language. Statements like SELECT or INSERT are intuitive enough for beginners to pick them up quickly.
3. Ability to Handle Large Data: SQL databases are designed to scale. It doesn’t matter if you have a few thousand or millions of records, SQL performs consistently, making it a great option for both small and enterprise operations.
4. Cross-Platform Compatibility: SQL is the industry standard for database management and querying, so you can apply your knowledge to almost any database system (Microsoft SQL, MySQL, PostgreSQL…).
5. Data Integrity and Consistency: SQL will make sure that your data remains consistent and reliable, even when many users are interacting with the database at the same time. This is critical in order to have up-to-date information without errors.
6. Advanced Capabilities: Advanced users can use features like joins, subqueries, and stored procedures, to perform complex data analysis and manipulation.

Here is a short video that explains what is SQL and what is it used for:

If you want, you can already download Microsoft SQL Server, before we start with the installation and setting up your first database.

Conclusion

SQL is an essential tool for anyone dealing with data. Whether you own a small business, develop enterprise applications, or analyze data, SQL offers endless possibilities for organizing and understanding data. It is very fast, really easy to learn, and versatile…and I really don’t know anyone who doesn’t use it one way or another.

In the next post, I will walk you through the steps of installing Microsoft SQL and setting up your first SQL database. Stay tuned!