20 Most Essential SQL Query Interview Questions & Answers
Table of Contents
- jaro education
- 21, October 2024
- 6:00 pm
SQL, or Structured Query Language, is the go-to programming language for managing and interacting with relational databases. It’s widely recognized across various fields, including data analytics, software development, and business operations, as a powerful tool for communicating with databases and extracting valuable insights from data.
Mastering SQL goes beyond just understanding its syntax—it’s about applying it in real-world situations. During the interview practical experience with SQL can showcase your ability to handle data efficiently. Whether you’re analyzing trends, optimizing queries, or managing databases, SQL proficiency can make you stand out in numerous tech-related roles.
When preparing for SQL interviews, expect to encounter questions that test not only your theoretical knowledge but also your problem-solving abilities in practical scenarios. To prepare for that we have created a list of the most asked SQL queries interview questions with practical examples that you can practice and gain deeper insight.
*vtricks.in
20 most asked SQL Queries Interview Questions
To start with SQL queries interview questions, We’ve designed three sample tables: the Student Table, Program Table, and Scholarship Table. These tables will serve as the foundation for demonstrating a variety of query operations.
Student Table
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 301 | Aarav | Mehta | 8.9 | 2024-01-15 9:00:00 | Data Science |
| 302 | Diya | Kapoor | 8.75 | 2024-01-15 8:45:00 | Mathematics |
| 303 | Siddharth | Joshi | 7.2 | 024-01-15 10:15:00 | Biology |
| 304 | Priya | Verma | 9.45 | 2024-01-15 11:00:00 | Chemistry |
| 305 | Aarohi | Sharma | 8.5 | 2024-01-15 9:30:00 | Physics |
| 306 | Vikram | Rao | 9.8 | 2024-01-15 10:45:00 | History |
| 307 | Riya | Patel | 9.6 | 2024-01-15 14:30:00 | English |
| 308 | Manav | Gupta | 7.85 | 2024-01-15 7:15:00 | Mathematics |
Program Table
| STUDENT_REF_ID | PROGRAM_NAME | PROGRAM_START_DATE |
|---|---|---|
| 301 | Data Science | 2024-01-15 0:00:00 |
| 302 | Mathematics | 2024-01-15 0:00:00 |
| 308 | Mathematics | 2024-01-15 0:00:00 |
| 305 | Physics | 2024-01-15 0:00:00 |
| 304 | Chemistry | 2024-01-15 0:00:00 |
| 307 | Psychology | 2024-01-15 0:00:00 |
| 306 | History | 2024-01-15 0:00:00 |
| 303 | Biology | 2024-01-15 0:00:00 |
Scholarship Table
| STUDENT_REF_ID | SCHOLARSHIP_AMOUNT | Scholarship Table |
|---|---|---|
| 301 | 5500 | 2022-02-10 0:00:00 |
| 302 | 4800 | 2022-03-18 0:00:00 |
| 303 | 3200 | 2022-05-25 0:00:00 |
| 304 | 4600 | 2022-06-15 0:00:00 |
| 305 | 5200 | 2022-04-20 0:00:00 |
| 306 | 6000 | 2022-07-10 0:00:00 |
| 307 | 5300 | 2022-08-18 0:00:00 |
| 308 | 4000 | 2022-09-25 0:00:00 |
1. Create a SQL query to retrieve "FIRST_NAME" from the Student table in uppercase, and utilize the ALIAS name as STUDENT_NAME.
You can use the SQL query below to answer this SQL query interview question that retrieves the “FIRST_NAME” from the “Student” table, converts it to upper case using the UPPER() function, and assigns it an alias name “STUDENT_NAME” for clarity in the result. This makes the output column name “STUDENT_NAME” instead of “FIRST_NAME”.
SQL query:Â
SELECT UPPER(FIRST_NAME) AS STUDENT_NAME
FROM Student;
Output:Â
| STUDENT_NAME |
|---|
| Aarav |
| DIYA |
| SIDDHARTH |
| PRIYA |
| AAROHI |
| VIKRAM |
| RIYA |
| MANAV |
2. Write a SQL query that prints the first three characters of FIRST_NAME from the Student table.
When the interviewer wants to know if you are aware of the SUBSTRING function, he might ask these types of SQL queries interview questions. Here is an explanation SQL query with output to answer these types of SQL queries interview questions:
The SQL query below selects the first three characters of the FIRST_NAME column from the “Student” table using the SUBSTRING function. This function is used to extract a substring starting from the first character of the name up to three characters.
SQL query
SELECT SUBSTRING(FIRST_NAME, 1, 3) AS First_Three_Chars
FROM Student;
Output:
| First_Three_Chars |
|---|
| Aar |
| Diy |
| Sid |
| Pri |
| Aar |
| Vik |
| Riy |
| Man |
3. Write a SQL query to find the location of the alphabet ('a') in the first name column 'Arav' of the Student table.
To find the position of the letter ‘a’ in the first name column of the Student table, we can use the SQL function INSTR (or POSITION in some databases). That is how you can showcase your expertise with the INSTR function to resolve this SQL queries interview question. This function returns the position of the first occurrence of the specified character in a string. Below is the SQL query for finding the location of ‘a’ in the first name ‘Aarav’ from the Student table.
SELECT STUDENT_ID, FIRST_NAME, INSTR(FIRST_NAME, ‘a’) AS Position_of_a
FROM Student
WHERE FIRST_NAME = ‘Aarav’;
Output:
| STUDENT_ID | FIRST_NAME | Table Position_of_aHeader |
|---|---|---|
| 301 | Aarav | 1 |
4. Develop an SQL query to retrieve the unique values of MAJOR Subjects from the Student table and report their length.
To solve this SQL queries interview quesiton, we need to retrieve the unique values of the MAJOR column from the Student Table and determine the length of each major’s name. We can use the DISTINCT keyword to get unique values and the LENGTH() function to calculate the length of each major’s name.
SQL query:Â
SELECT DISTINCT MAJOR, LENGTH(MAJOR) AS MAJOR_LENGTH
FROM Student_Table;
Output
| MAJOR | MAJOR_LENGTH |
|---|---|
| Data Science | 12 |
| Mathematics | 11 |
| Biology | 7 |
| Chemistry | 9 |
| Physics | 7 |
| History | 7 |
| Data Science | 7 |
5. Create a SQL query that prints FIRST_NAME from the Student table, replacing 'a' with 'A'.
The SQL query below selects the FIRST_NAME from the “Student Table” and replaces all occurrences of the letter ‘a’ with ‘A’ using the REPLACE() function. This ensures that every ‘a’ in the first names is converted to ‘A’ in the output. Use SQL query given below to resolve these interview questions.
SQL query:Â
SELECT REPLACE(FIRST_NAME, ‘a’, ‘A’) AS FIRST_NAME
FROM Student;
Output:
| FIRST_NAME |
|---|
| AArAv |
| DiyA |
| SiddhArth |
| PriyA |
| Aarohi |
| VikrAm |
| RiyA |
| MAnAv |
6. Create a SQL query to print information about students whose FIRST_NAME ends with 'a' and contains six alphabets.
To find students whose FIRST_NAME ends with the letter ‘a’ and contains exactly six alphabets, we can use the WHERE clause in SQL query with string functions such as LIKE and LENGTH and resolve this interview quesiton. The LIKE operator will help us filter names that end with ‘a’, and the LENGTH function will ensure the name has six characters.
SQL query:Â
SELECT STUDENT_ID, FIRST_NAME, LAST_NAME, GPA, ENROLLMENT_DATE, MAJOR
FROM Student_Table
WHERE FIRST_NAME LIKE ‘_____a’
AND LENGTH(FIRST_NAME) = 6;
Output will be none.Â
7. Build a SQL query to print information about students with GPAs between 9.00 and 9.99.
The SQL query below returns information on students with GPAs between 9.00 and 9.99. It picks appropriate columns from the “Student Table” depending on the GPA requirement. This will exclude students with GPAs within the stated range.
SQL query:Â
SELECT STUDENT_ID, FIRST_NAME, LAST_NAME, GPA, ENROLLMENT_DATE, MAJOR
FROM StudentTable
WHERE GPA BETWEEN 9.00 AND 9.99;
Output
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 304 | Priya | Verma | 9.45 | 2024-01-15 11:00:00 | Chemistry |
| 306 | Vikram | Rao | 9.8 | 2024-01-15 10:45:00 | History |
| 307 | Riya | Patel | 9.6 | 2024-01-15 | English |
8. Create a query to retrieve the last record from the Scholarship table.
To resolve SQL queries interview questions like retrieving the last data we can order the records by the SCHOLARSHIP_DATE in descending order and then limit the result to just one row, ensuring we get the most recent entry.Â
SQL query:Â
SELECT *
FROM ScholarshipTable
ORDER BY SCHOLARSHIP_DATE DESC
LIMIT 1;
Output
| 308 | 4000 | 2022-09-25 0:00:00 |
9. Write an SQL query to retrieve the second-highest value of an integer field from the student table.
To get the second-highest value of an integer field from a table, we can use the SQL query with the MAX function and a subquery and answer this interview quesiton. The subquery will exclude the maximum value, allowing us to get the second-highest value. For example, to find the second-highest GPA from the Student Table, we will use the following query:
SELECT MAX(GPA) AS second_highest_gpa
FROM StudentTable
WHERE GPA < (SELECT MAX(GPA) FROM StudentTable);
Output:
| second_highest_gpa |
|---|
| 9.6 |
10. Use the WHERE clause to create a query to view a specific record from the table
In SQL, the WHERE clause is used to filter records that meet specific conditions. We will apply the WHERE clause to resolve this interview question for SQL queries and you can retrieve a particular record from a table based on criteria such as student ID, GPA, or name.
Here is an SQL query that retrieves the record of a student whose STUDENT_ID is 301 from the Student Table:
SELECT *
FROM Student_Table
WHERE STUDENT_ID = 301;
Output:
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 301 | Aarav | Mehta | 8.9 | 2024-01-15 9:00:00 | Data Science |
11. Create a SQL query to retrieve the number of students with the Major Subject 'Mathematics’
To count the number of students who have “Mathematics” as their major, we can use a SELECT query with the WHERE condition to filter by the major. The COUNT() function will then give the number of students matching the condition and can answer these SQL query interview questions.Â
SQL query:Â
SELECT COUNT(*) AS number_of_students
FROM Student_Table
WHERE MAJOR = ‘Mathematics’;
Output will be 2.Â
12. Create a SQL query to retrieve students' full names with GPA >= 8.5 and <= 9.5.
The SQL query below retrieves the full names (first and last names) of students who have a GPA between 8.5 and 9.5 (inclusive). This condition filters students within the specified GPA range from the “Student Table.”
SQL query:
| FIRST_NAME | LAST_NAME |
|---|---|
| Aarav | Mehta |
| Diya | Kapoor |
| Priya | Verma |
| Aarohi | Sharma |
SQL query:Â
WITH NumberedRows AS (
    SELECT STUDENT_ID, FIRST_NAME, LAST_NAME, GPA, ENROLLMENT_DATE, MAJOR,
           ROW_NUMBER() OVER (ORDER BY STUDENT_ID) AS RowNum
    FROM Student
)
SELECT STUDENT_ID, FIRST_NAME, LAST_NAME, GPA, ENROLLMENT_DATE, MAJOR
FROM NumberedRows
WHERE RowNum % 2 = 1;
If you have good experience and applied for an interview you might be asked sql interview queries for experienced professionals. Here is the explanation and output:
- The ROW_NUMBER() function assigns sequential row numbers to each record based on STUDENT_ID ordering.
- We then filter the rows where the RowNum is odd (RowNum % 2 = 1).
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 301 | Aarav | Mehta | 8.9 | 2024-01-15 9:00:00 | Data Science |
| 303 | Siddharth | Joshi | 7.2 | 024-01-15 10:15:00 | Biology |
| 305 | Aarohi | Sharma | 8.5 | 2024-01-15 9:30:00 | Physics |
| 307 | Riya | Patel | 9.6 | 2024-01-15 14:30:00 | English |
14. Create an SQL query to display only odd rows from the Student table.
SQL query:Â
SELECT *Â
FROM StudentÂ
WHERE MOD(STUDENT_ID, 2) = 0;
Here is an explanation to answer these types of SQL queries interview questions:
-
- The MOD(STUDENT_ID, 2) function returns the remainder when the STUDENT_ID is divided by 2.
- The query selects all rows where the STUDENT_ID is even (i.e., the remainder is 0).
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 302 | Diya | Kapoor | 8.75 | 2024-01-15 8:45:00 | Mathematics |
| 304 | Priya | Verma | 9.45 | 2024-01-15 11:00:00 | Chemistry |
| 306 | Vikram | Rao | 9.8 | 2024-01-15 10:45:00 | History |
| 308 | Manav | Gupta | 7.85 | 2024-01-15 7:15:00 | Mathematics |
15. Create a SQL query to find the nth (say, n=5) highest GPA in a table.
SQL query:Â
SELECT GPA
FROM (
    SELECT GPA, DENSE_RANK() OVER (ORDER BY GPA DESC) AS rank
    FROM Student_Table
) AS Ranked_GPA
WHERE rank = 5;
Here is an explanation to answer these types of SQL queries interview questions:
-
- The query uses the DENSE_RANK() function to assign a rank to each unique GPA in descending order (highest to lowest).
- Then, we filter the results to return the GPA with a rank of 5, which corresponds to the 5th highest GPA in the table.
16. Create a SQL query to find the fifth highest GPA without using the LIMIT keyword.
SQL query:Â
SELECT GPA
FROM Student_Table s1
WHERE 4 = (SELECT COUNT(DISTINCT s2.GPA)
           FROM Student_Table s2
           WHERE s2.GPA > s1.GPA);
Here is an explanation to answer these types of SQL queries interview questions:
-
- The query compares each GPA with other distinct GPA values in a subquery. The subquery counts how many distinct GPAs are greater than the current row’s GPA.
- By ensuring that exactly four GPAs are greater, the outer query returns the fifth-highest GPA. This avoids the use of LIMIT.
17. Create a SQL statement that uses a subquery to display the second highest GPA from a Student table.
SQL query:Â
SELECT MAX(GPA) AS Second_Highest_GPA
FROM Student
WHERE GPA < (SELECT MAX(GPA) FROM Student);
Here is an explanation to answer these types of SQL queries interview questions:
-
- The sub-query (SELECT MAX(GPA) FROM Student) fetches the highest GPA from the Student table.
- The outer query then retrieves the maximum GPA that is less than the highest GPA, which gives the second-highest GPA.
18. Write a SQL query to retrieve the MAJOR subjects with fewer than four persons.
SQL query:Â
SELECT MAJOR, COUNT(STUDENT_ID) AS Student_Count
FROM StudentTable
GROUP BY MAJOR
HAVING COUNT(STUDENT_ID) < 4;
Here is an explanation to answer these types of SQL queries interview questions:
-
- The query groups the students by their MAJOR and counts how many students are enrolled in each subject using the COUNT function.
- The HAVING clause filters the result to only show MAJOR subjects where the count of students is fewer than four.
| MAJOR | Student_Count |
|---|---|
| Data Science | 1 |
| Biology | 1 |
| Chemistry | 1 |
| Physics | 1 |
| History | 1 |
| English | 1 |
19. Create an SQL query to display the last record in a table
SQL query:Â
SELECT *
FROM StudentTable
ORDER BY STUDENT_ID DESC
LIMIT 1;
Here is an explanation to answer these types of SQL queries interview questions:
-
- The ORDER BY STUDENT_ID DESC ensures the records are sorted in descending order by the STUDENT_ID column, making the last record appear first.
- LIMIT 1 ensures that only the first record from the sorted result is returned, which is effectively the last record of the original table.
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 308 | Manav | Gupta | 7.85 | 2024-01-15 7:15:00 | Mathematics |
20. Create a SQL query to retrieve the last five records from a table.
SQL query:Â
SELECT *
FROM Student_Table
ORDER BY STUDENT_ID DESC
LIMIT 5;
Here is an explanation to answer these types of SQL queries interview questions:
-
- This query selects all columns from the “Student Table” and orders the records by STUDENT_ID in descending order (from highest to lowest).
- The LIMIT 5 clause restricts the result to the last five records based on the descending order, showing the most recent entries.
| STUDENT_ID | FIRST_NAME | LAST_NAME | GPA | ENROLLMENT_DATE | MAJOR |
|---|---|---|---|---|---|
| 308 | Manav | Gupta | 7.85 | 2024-01-15 7:15:00 | Mathematics |
| 307 | Riya | Patel | 9.6 | 2024-01-15 14:30:00 | English |
| 306 | Vikram | Rao | 9.8 | 2024-01-15 10:45:00 | History |
| 305 | Aarohi | Sharma | 8.5 | 2024-01-15 9:30:00 | Physics |
| 304 | Priya | Verma | 9.45 | 2024-01-15 11:00:00 | Chemistry |
Final Thoughts
Anyone interested in working as a data analyst, data engineer, or business analyst must be able to answer SQL queries interview questions well. This resource includes a thorough set of SQL queries interview questions and answers, giving you the tools you need to succeed in your interviews. To learn further Jaro Education offers comprehensive, industry-relevant courses such as Executive Programme in Full Stack Web Development that simplify learning SQL queries, helping you build practical skills through hands-on experience. With expert guidance, you’ll master SQL techniques essential for excelling in data-driven roles.
You may confidently demonstrate your SQL proficiency—a key ability that facilitates data processing, analysis, and decision-making across tech-driven industries—by becoming familiar with and practicing these queries. With proper preparation, you will be well-equipped to stand out in your interview and land your chosen position.
Frequently Asked Questions
Related Program
Trending Blogs
