If you’re a fresher trying to start your career in tech, SQL is one of the most common topics you’ll face in interviews. Whether it’s for a data analyst role or software job, knowing basic SQL gives you a strong start. In this blog, we’ll go over important SQL questions and explain them in very easy terms. This will help you understand the logic, not just memorise the answers.
What is SQL?
SQL stands for Structured Query Language. It is used to work with data inside a database. With SQL, you can add new records, find specific information, update data or delete old entries. Most companies use SQL to manage data because it is fast and reliable.
Common Questions You Might Face
- Difference between WHERE and HAVING
WHERE is used to filter data before grouping.
HAVING is used after grouping the data.
So, if you want to find departments that have more than 5 employees, you’ll use HAVING.
- What is a Primary Key?
A primary key is something that makes each row in a table unique. It can be one column or more than one column together.
What Are SQL JOINS?
You might get questions like these in interviews:
INNER JOIN: Shows only matching rows from both tables
LEFT JOIN: Shows all rows from the left table, and matching ones from the right
RIGHT JOIN: Shows all rows from the right table, and matching ones from the left
FULL OUTER JOIN: Shows all rows from both tables
Other Basic Concepts:
DELETE vs TRUNCATE vs DROP
DELETE removes selected data
TRUNCATE removes all rows quickly
DROP removes the table itself
Foreign Key: Used to connect two tables
Normalization: Organising data to reduce repetition
Subqueries: A query written inside another query
How to Prepare Better?
Spend 30–45 minutes daily practicing SQL
Use free online tools to write and test queries
Try small real-world problems like "List employees who joined in last 3 months"
Join beginner-friendly courses in your local language
Practice mock interviews with your friends
Final Thoughts
If you are new to SQL and just finished college, don’t get scared by long definitions or advanced syntax. Start with basic questions, understand how queries work, and keep practicing daily. Over time, you’ll be confident enough to answer most SQL interview questions with ease.
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