Top 100 SQL Interview Questions & Answers

#SQL #InterviewQuestions #DataAnalysis #Database #SQLQueries

Part 1: Basic Queries & DML/DDL (Q1-20)

#1. Select all columns and rows from a table named products.
A: Use SELECT * to retrieve all columns.

SELECT *
FROM products;

Output: All data from the 'products' table.

#2. Select only the product_name and price columns from the products table.
A: List the desired column names.

SELECT product_name, price
FROM products;

Output: A table with two columns: 'product_name' and 'price'.

#3. Find all products with a price greater than 50.
A: Use the WHERE clause with a comparison operator.

SELECT product_name, price
FROM products
WHERE price > 50;

Output: Products whose price is more than 50.

#4. Find all products that are red or have a price less than 20.
A: Use WHERE with OR to combine conditions.

SELECT product_name, color, price
FROM products
WHERE color = 'Red' OR price < 20;

Output: Products that are red OR cheaper than 20.

#5. Find all products that are red AND have a price greater than 100.
A: Use WHERE with AND to combine conditions.

SELECT product_name, color, price
FROM products
WHERE color = 'Red' AND price > 100;

Output: Products that are red AND more expensive than 100.

#6. Select all unique category values from the products table.
A: Use the DISTINCT keyword.

SELECT DISTINCT category
FROM products;

Output: A list of unique categories (e.g., 'Electronics', 'Books').

#7. Count the total number of products in the products table.
A: Use the COUNT(*) aggregate function.

SELECT COUNT(*) AS total_products
FROM products;

Output: A single number representing the total count.

#8. Find the average price of all products.
A: Use the AVG() aggregate function.

SELECT AVG(price) AS average_price
FROM products;

Output: A single number representing the average price.

#9. Find the highest and lowest price among all products.
A: Use the MAX() and MIN() aggregate functions.

SELECT MAX(price) AS highest_price, MIN(price) AS lowest_price
FROM products;

Output: Two numbers: the maximum and minimum price.

#10. Sort products by price in ascending order.
A: Use ORDER BY with ASC (or omit ASC as it's the default).

SELECT product_name, price
FROM products
ORDER BY price ASC;

Output: Products listed from cheapest to most expensive.

#11. Sort products by price in descending order.
A: Use ORDER BY with DESC.

SELECT product_name, price
FROM products
ORDER BY price DESC;

Output: Products listed from most expensive to cheapest.

#12. Sort products by category (ascending), then by price (descending).
A: Specify multiple columns in ORDER BY.

SELECT product_name, category, price
FROM products
ORDER BY category ASC, price DESC;

Output: Products grouped by category, then sorted by price within each category.

300 Real Time SQL Interview practical Questions Asked at multiple companies
••••••••••••••••••••••••••••••••••••••••••••••••••••••

Anyone who's preparing for an interview just reading theoretical concept will not help definitely you need to have practical hands on in #sql so create table with some data and try this queries running by your self so can help you to understand the logic of similar kind of queries

If you're preparing for an interview this doc will help a lot in the perpetration If you're experienced also freshers can also get hands on by practicing these queries and get confidence.

https://t.iss.one/DataScienceQ