Practice SQL Basics Interview Questions

Q: Return a text value using SELECT

Write and run the SQL query in the interactive editor above to check your answer.

Q: Calculate a simple arithmetic expression

Write and run the SQL query in the interactive editor above to check your answer.

Q: Return multiple expressions in one query

Write and run the SQL query in the interactive editor above to check your answer.

Q: Fetch all rows and columns from the products table

Write and run the SQL query in the interactive editor above to check your answer.

Q: Fetch all rows and columns from the customers table

Write and run the SQL query in the interactive editor above to check your answer.

Q: Select specific columns from the orders table

Write and run the SQL query in the interactive editor above to check your answer.

SQL (Structured Query Language) is the standard language for querying and managing relational databases. In technical interviews, whether for analyst, engineer, or data science roles, SQL basics are non-negotiable. Interviewers use these questions to filter out candidates fast.

SQL Basics covers what the language is, how it is structured, and how to write correct, readable queries from the first line. Every advanced SQL concept like joins, window functions, and CTEs depends on getting this right.

What SQL Covers

SQL is divided into sublanguages based on what you are doing:

Category	Full Form	Purpose	Common Statements
DQL	Data Query Language	Query data	SELECT
DML	Data Manipulation Language	Modify data	INSERT, UPDATE, DELETE
DDL	Data Definition Language	Define structure	CREATE, ALTER, DROP
DCL	Data Control Language	Control access	GRANT, REVOKE
TCL	Transaction Control Language	Manage transactions	COMMIT, ROLLBACK

Most interviews focus heavily on DQL — writing SELECT queries that return the right data.

Syntax

SELECT column1, column2
FROM table_name
WHERE condition
ORDER BY column1 ASC
LIMIT n;

Key rules:

SQL keywords are case-insensitive. SELECT and select behave identically
Each statement ends with a semicolon
Column and table names are case-sensitive depending on the database engine
Whitespace and line breaks do not affect execution
SELECT without a FROM clause is valid. SQL evaluates the expression directly

Example — run it and see

SELECT
    product_id,
    name,
    price
FROM products
ORDER BY price DESC
LIMIT 5;

Practice Questions

Return a text value using SELECT

💡 No FROM needed. Just SELECT the text directly as a string literal.

SOLUTION

SELECT 'Hello, SQL!'

Calculate a simple arithmetic expression

💡 Write the expression inside SELECT and alias the output as result.

SOLUTION

SELECT 25 * 100 AS result

Return multiple expressions in one query

SOLUTION

SELECT 'SQLround' AS site, 100 AS score, 50 * 2 AS calculated

Fetch all rows and columns from the products table

💡 Use * to select all columns. No WHERE, no ORDER BY needed.

SOLUTION

SELECT * FROM products

Fetch all rows and columns from the customers table

SOLUTION

SELECT * FROM customers

Select specific columns from the orders table

💡 Name only the two required columns. Avoid SELECT * here.

SOLUTION

SELECT order_id, order_date FROM orders