Structured Query Language or SQL is one of the most in-demand skills for Data Scientists. From Facebook to Netflix to Microsoft; all leading companies look for Data Scientists with SQL skills in their toolkit. So, if you are interviewing for a Data Scientist role, you should expect some questions on SQL.
The best way to prepare SQL concepts for a Data Scientist interview is to practice commonly asked questions. In this article, we have curated an exclusive list of the top 15 SQL questions (with answers) asked in Data Scientist interviews. With these SQL questions, you can brush up on your basics, practice, and prepare for your Data Scientist interview.
So, without further ado, let’s start practicing.
Data Science Interview Questions on SQL
This list of SQL Data Science interview questions covers concepts such as database, tables, SQL commands, and SQL queries on select. Check them out below.
1. What is the difference between SQL and MySQL?
SQL is used for manipulating structured databases. While MySQL is a relational database management system, like SQL Server, Oracle, Postgres, or IBM DB2; used to manage SQL databases.
Did you know: The correct pronunciation of SQL is “SEQUEL”
2. What are fields in a database?
In a database table, the number of columns is specified and is known as fields.
3. Explain the difference between DML and DQL commands in SQL.
The DML command stands for Data Manipulation Language. It is used to manage the data. On the other hand, DQL stands for Data Query Language. DQL commands are used to retrieve data from the database. All select queries come under DQL.
4. What is the use of DDL commands in SQL?
DDL stands for Data Definition Language. It is used to define the structure of the database
5. Write a query to create an employee table with 4 fields id, name, dept, sal in an appropriate datatype.
6. Create an employee table with a primary key as id in the salary database.
7. Write a query to select id, name from employee table.
8. Fetch the id using the alias name “empID” from the employee table.
9. Write a query to count the total number of unique dept from the employee table using the alias name “UniqueDept”.
10. Fetch minimum salary employee details from the employee table.
11. Fetch the employee’s name from the employee table after removing blank spaces (left and right).
12. Write a query to retrieve the 10th highest employee salary.
13. Write a query to find the names of employees starting with ‘V’ from the employee table.
The LIKE operator is used to get specific data by searching in the where clause.
14. When is the “BETWEEN” operator used in SQL?
The BETWEEN operator in SQL is used when you want to select rows according to value range.
15. How is IN operator different from BETWEEN operator in SQL?
To check for values in a specific set, the IN operator is used. While for choosing rows based on values or range of values, a BETWEEN operator is used.
These are some popular SQL questions often asked in Data Scientist interviews. Now that you’re interviewing for a Data Scientist role, you must wonder what the day-to-day activities of a Data Scientist are. Check out our article- A day in the life of a Data Scientist and get all your questions answered.
PinWe hope you found this article useful. In our next blog, we will be covering more in-depth SQL Data Science interview questions. Stay tuned!
