5 most asked SQL Interview Questions for Data Engineer jobs.

𝟭. 𝗙𝗶𝗻𝗱 𝘁𝗵𝗲 𝗦𝗲𝗰𝗼𝗻𝗱 𝗛𝗶𝗴𝗵𝗲𝘀𝘁 𝗦𝗮𝗹𝗮𝗿𝘆 𝗶𝗻 𝗮 𝗧𝗮𝗯𝗹𝗲

SELECT MAX(salary) AS SecondHighestSalary
FROM Employee
WHERE salary < (SELECT MAX(salary) FROM Employee);

𝟮 . 𝗙𝗶𝗻𝗱 𝗼𝘂𝘁 𝗲𝗺𝗽𝗹𝗼𝘆𝗲𝗲𝘀 𝗲𝗮𝗿𝗻𝗶𝗻𝗴 𝗺𝗼𝗿𝗲 𝘁𝗵𝗮𝗻 𝘁𝗵𝗲𝗶𝗿 𝗺𝗮𝗻𝗮𝗴𝗲𝗿𝘀

SELECT e2.name as Employee
FROM employee e1
INNER JOIN employee e2
ON e1.id = e2.managerID
WHERE e1.salary < e2.salary

𝟯. 𝗙𝗶𝗻𝗱 𝗰𝘂𝘀𝘁𝗼𝗺𝗲𝗿𝘀 𝘄𝗵𝗼 𝗻𝗲𝘃𝗲𝗿 𝗼𝗿𝗱𝗲𝗿

SELECT name as Customers
FROM Customers
WHERE id not in (
SELECT customerId
FROM Orders);

𝟰. 𝗗𝗲𝗹𝗲𝘁𝗲 𝗱𝘂𝗽𝗹𝗶𝗰𝗮𝘁𝗲 𝗲𝗺𝗮𝗶𝗹𝘀

DELETE p1
FROM Person p1, Person p2
WHERE p1.Email = p2.Email AND
p1.Id > p2.Id

𝟱. 𝗖𝗼𝘂𝗻𝘁 𝘁𝗵𝗲 𝗻𝘂𝗺𝗯𝗲𝗿 𝗼𝗳 𝗼𝗿𝗱𝗲𝗿𝘀 𝗽𝗹𝗮𝗰𝗲𝗱 𝗶𝗻 𝘁𝗵𝗲 𝗽𝗿𝗲𝘃𝗶𝗼𝘂𝘀 𝘆𝗲𝗮𝗿 𝗮𝗻𝗱 𝗺𝗼𝗻𝘁𝗵.

SELECT COUNT(*) AS order_count
FROM orders WHERE EXTRACT(YEAR_MONTH FROM order_date) = EXTRACT(YEAR_MONTH FROM CURDATE() - INTERVAL 1 MONTH);

💡 Note: SQL interview questions vary widely based on the specific role and company. So you also need to practice questions your target companies ask.

Data Engineering Interview Preparation Resources: https://whatsapp.com/channel/0029Vaovs0ZKbYMKXvKRYi3C

All the best 👍👍