SQL for Beginners: Queries Every Data Analyst Must Know

SQL for Beginners: Queries Every Data Analyst Must Know

Structured Query Language (SQL) is the foundation of data analysis. Whether you’re exploring business data, preparing reports, or supporting machine learning models, SQL helps you communicate with databases. For beginners, learning SQL is one of the most valuable skills you can acquire as a data analyst.

In this guide, we’ll cover the essential SQL queries every beginner must know. These commands will help you retrieve, filter, summarize, and manage data. These skills are directly applicable in real-world analysis.

1. SELECT

The SELECT statement is the backbone of SQL. It retrieves data from one or more tables.

SELECT first_name, last_name, department
FROM employees;

This query fetches employee names and their departments from the employees table.

2. WHERE

The WHERE clause allows you to filter rows based on conditions.

SELECT *
FROM sales
WHERE revenue > 1000;

Returns only sales records where revenue exceeds 1000.

3. ORDER BY

Use ORDER BY to sort data in ascending (ASC) or descending (DESC) order.

SELECT product, revenue
FROM sales
ORDER BY revenue DESC;

Displays products sorted by highest revenue first.

4. GROUP BY

GROUP BY helps you group rows and apply aggregate functions like COUNT, SUM, or AVG.

SELECT department, AVG(salary) AS avg_salary
FROM employees
GROUP BY department;

Finds the average salary for each department.

5. JOIN

SQL joins allow you to combine data from multiple tables.

SELECT employees.first_name, departments.department_name
FROM employees
JOIN departments
ON employees.department_id = departments.id;

Returns employee names along with their department names.

6. INSERT

The INSERT statement adds new rows into a table.

INSERT INTO employees (first_name, last_name, department)
VALUES ('John', 'Doe', 'Finance');

Inserts a new employee into the employees table.

7. UPDATE

Use UPDATE to change existing records.

UPDATE employees
SET salary = 60000
WHERE employee_id = 5;

Updates the salary of the employee with ID 5.

8. DELETE

The DELETE statement removes rows from a table.

DELETE FROM employees
WHERE department = 'HR';

Deletes all employees from the HR department.

9. LIMIT

LIMIT restricts how many rows are returned.

SELECT *
FROM sales
LIMIT 10;

Fetches the first 10 rows from the sales table.

10. CREATE TABLE

For beginners, knowing how to create a simple table is crucial.

CREATE TABLE employees (
    employee_id INT PRIMARY KEY,
    first_name VARCHAR(50),
    last_name VARCHAR(50),
    salary DECIMAL(10,2)
);

Creates a basic employees table with columns for ID, name, and salary.

SQL is the universal language of data. As a beginner, mastering these queries will give you a strong foundation to retrieve, manipulate, and analyze data effectively. Over time, you can build on these basics to learn advanced concepts like subqueries, indexes, and stored procedures.

FAQs

Q1: Is SQL hard for beginners?
No, SQL is one of the easiest programming languages to learn because of its simple, English-like syntax.

Q2: Do data analysts need SQL?
Absolutely. SQL is a core skill for any data analyst or data scientist.

Q3: Can I use SQL without coding experience?
Yes, SQL is beginner-friendly and widely used by non-programmers.

Q4: What’s the difference between SQL and Excel?
Excel works best for small datasets, while SQL handles large, structured databases.

Q5: How long does it take to learn SQL?
With consistent practice, beginners can learn SQL basics in 2–4 weeks.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top