Introduction
If you want to get into roles like data analyst or data scientist, then you must master this advanced MySQL interview question to meet the demands of these positions. In this blog, I have compiled the Top 50 Advanced Interview Questions with answers to help you prepare for your upcoming interview.
Top 50 Advanced MySQL Interview Questions
1. What is the difference between PostgreSQL and MySQL?
| PostgreSQL | MySQL |
|---|---|
| PostgreSQL is an object-relational database management system and supports multiple indexes. | Whereas, MySQL is a relational database management system, and it supports B-tree and R-tree indexes. |
| PostgreSQL supports data types such as numeric, character, date and time, spatial, and JSON. | MySQL supports enumerated, network addresses, arrays, ranges, XML, hstore, composite, and MySQL data types. |
2. What are the most common functions in MySQL Server?
The most used functions in MySQL servers are String functions, Numeric functions, Date and time functions, Aggregate functions, and Other functions.
- String functions consist of CONCAT(), LEFT(), RIGHT() & SUBSTRING() LEN(), LTRIM(), RTRIM() & TRIM(), REPLACE(), LOWER() and UPPER().
- Numeric functions contain ABS(), and ROUND().
- Data and time functions consist of DATEDIFF(), CURRENT_TIMESTAMP(), DATEADD(), DAY(), MONTH(), YEAR().
- Aggregate functions consist of COUNT(), SUM(), AVG(), MIN(), and MAX().
- Lastly, CAST() & CONVERT(), COALESCE(), ISNULL(), and NULLIF() comes under other functions.
3. Write the MySQL query to find the 5 highest-paid salaries of employees for each department in descending order.
Let’s assume that we have an Employee table with columns emp_id, dept_id, and salary. The following is a query to retrieve the 5 highest-paid salaries for employess in descending order:
WITH RankedEmployees AS (
SELECT
employee_id,
department_id,
salary,
ROW_NUMBER() OVER (PARTITION BY department_id ORDER BY salary DESC) AS rank
FROM employees
)
SELECT
employee_id,
department_id,
salary
FROM RankedEmployees
WHERE rank <= 5
ORDER BY department_id, rank; Must Read: What is an SQL Database?
4. Imagine there is a StudentDonationtable that contains fees paid by the students. Write a MySQL query to find out the Nth highest donation paid by the student without using TOP and LIMIT Operator.
SELECT Donation
FROM StudentDonationTable F1
WHERE N-1 = (
SELECT COUNT( DISTINCT ( F2.Donation ) )
FROM StudentDonationTable F2
WHERE F2.Donation > F1.Donation );5. What are the three reasons for using Function in MySQL?
- T§ The author
Top 50 Advanced MySQL Interview Questions
Top 50 advanced MySQL interview question with answers to help you tackle the complex question for your upcoming MySQL interview.
Filed under50 Advanced MySQL Interview QuestionsReading time6 min · 1,112 words
PublishedApril 19, 2024
Category50 Advanced MySQL Interview Questions
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