Getting Started with SQL

In today’s data-driven world, understanding data is as important as creating it. Whether you’re in marketing, finance, HR, or IT, chances are you’ve encountered a situation where you needed to retrieve or analyze data from a database.

It’s Monday morning. You’re in the office, and just as you’re settling in with your coffee, your boss says,
“Can you pull up last quarter’s sales trends? I need them in 10 minutes.”

You panic—for a moment. Then you remember: the data is there, tucked neatly in your company’s database. All you need is the right question. And in the language of data, that question is asked through SQL.

What is SQL?

SQL stands for Structured Query Language. It’s the standard language used to communicate with databases and helps retrieve, insert, update, and delete data. SQL is the go-to language.

Think of SQL as a way to ask your database questions just like you’d ask Google but instead of searching the web, you’re searching through neatly organized tables of data. SQL is specifically designed to work with relational databases. It allows you to manage and query that tabular data efficiently.

What is a Relational Database?

A relational database is a type of database that stores data in tables just like a spreadsheet with rows and columns. Each table is designed to store information about a specific topic, and the tables can be linked or “related” to each other using keys.

Table – Entity

Row – Record (or an instance of that entity)

Column – Attributes (properties of that entity)

Data in one table can relate to data in another table that’s why it’s called relational. This makes it easy to organize, search, and maintain complex data without repeating it

For example:

Employee_ID	Name	Department
101	Aman	IT
102	Amanpreet	HR

These tables can be linked based on common data (like Employee_ID) that’s the “relational” part.

Why Should You Learn SQL?

In a world flooded with data, SQL (Structured Query Language) is one of the most valuable skills you can have:

Universally Used: Almost every company uses databases.
Data Access: Easily pull the data you need without relying on developers.
Career Growth: Opens up roles in analytics, business intelligence, data science, and more.
No Coding Background Needed: SQL is beginner-friendly. You don’t need to be a programmer.
Automate & Save Time: Manually checking Excel sheets? SQL can automate the data retrieval process, saving hours of work.

SQL Data Types

SQL data types define what kind of data can be stored in each column of a table. They help the database understand how to store, process, and validate the data whether it’s text, numbers, dates, or something else.

There are several groups of SQL data types:

1. Numeric Data Type: Store numbers and support mathematical operations like addition, subtraction, multiplication, and division making them essential for calculations and data analysis.

Data Type	Description	Range
INT	Standard integer values	-2,147,483,648 to 2,147,483,647
DECIMAL	Exact fixed-point numbers (e.g., for financial values)	-10^38 + 1 to 10^38 – 1
NUMERIC	Similar to DECIMAL, used for precision data	-10^38 + 1 to 10^38 – 1

2. Character Data Type: Character data types in SQL are used to store text, with options for fixed or variable length depending on the data’s size and consistency.

Data Type	Description
Char	The maximum length of 8000 characters. (Fixed-Length non-Unicode Characters)
Varchar	The maximum length of 8000 characters. (Variable-Length non-Unicode Characters)

3. Date and Time Data Types: SQL provides several data types for storing date and time information. They are essential for managing timestamps, events, and time-based queries. These are given in the below table.

Data Type	Table Header	Table Header
Date	stores the data of date (year, month, day)	3 Bytes
Time	stores the data of time (hour, minute, second)	3 Bytes

4. Boolean Data Type in SQL: The BOOLEAN data type stores logical values like TRUE or FALSE and is often used for flags or yes/no conditions in a database.

Data Type	Description
Boolean	Stores a logical value (TRUE/FALSE)

Basic SQL Commands You Should Know

There are a few core commands that form the foundation of most database interactions. Let’s walk through them with simple explanations:

1. SELECT – Retrieves data from a table

The SELECT statement is used to fetch data from a database table.

SELECT * FROM Customers;

This command pulls all columns (*) from the Customers table

2. WHERE – Filter Data

Used with SELECT, UPDATE, or DELETE to specify conditions.

SELECT * FROM Customers WHERE Country = 'India';

Fetches only those customers who are from India.

3. INSERT INTO – Add New Data

Adds a new record to a table.

INSERT INTO Customers (Name, Country) VALUES ('Aryan', 'India');

Adds a new customer named Aryan from India.

4. UPDATE – Change Existing Data

Modifies existing records in a table.

UPDATE Customers SET Country = 'USA' WHERE Name = 'Aryan';

Changes Aryan’s country to USA.

5. DELETE – Remove Data

Deletes one or more records from a table.

DELETE FROM Customers WHERE Name = 'Aryan';

Removes Aryan from the Customers table.

6. CREATE TABLE – Make a New Table

Creates a new table structure in the database.

CREATE TABLE Products ( ProductID INT, Name VARCHAR(50), Price DECIMAL(10, 2) );

Makes a Products table with columns for ID, name, and price.

7. JOIN – Combine Data from Multiple Tables

Used to fetch data from two or more related tables.

SELECT Customers.Name, Orders.Amount FROM Customers JOIN Orders ON Customers.CustomerID = Orders.CustomerID;

Combines customer names with their order amounts.

These basic commands are just the tip of the iceberg but mastering them will allow you to start asking powerful questions from your data and getting instant answers. Whether you’re running reports, automating processes, or digging for insights, SQL is your key to unlocking data.

Real-Life Example

Imagine you’re in HR and need a list of all employees in the IT department. Instead of scrolling through spreadsheets, one SQL line does the trick:

Sql:

SELECT Name FROM employees WHERE Department = 'IT';

With just one line of SQL, you’ve filtered your employee list by department—saving time and reducing errors.

Conclusion

SQL may sound technical, but it’s actually easy to learn and extremely useful in everyday work. Whether you’re in HR, marketing, finance, or any other field, knowing how to work with data gives you a big advantage.

With just a few basic commands, you can find, filter, and manage data quickly no more digging through spreadsheets or waiting for someone else to do it.

So if you’ve ever asked, “Where can I find this data?” or “How can I save time with reports?”

the answer is simple: learn SQL.

It’s your first step toward becoming more confident, independent, and data-smart at work.

By – Aryan Kothiyal

Getting Started with SQL

A Beginner-Friendly Guide for Working Professionals