11 NetApp SQL Interview Questions (Updated 2024)

At NetApp, SQL is used day-to-day for analyzing complex data to optimize storage solutions and managing large-scale databases to enhance cloud data services. They also provide services to store Microsoft SQL server databases. Because of this, NetApp often tests SQL problems during interviews for Data Analytics, Data Science, and Data Engineering jobs.

To help you practice for the NetApp SQL interview, this blog covers 11 NetApp SQL interview questions – able to answer them all?

11 NetApp SQL Interview Questions

SQL Question 1: Analyze Monthly Average Rating per Product

Write a SQL query to find out the monthly average rating for each NetApp product. We want the result to include a separate row for each month when at least one rating was submitted for a given product. The months should be represented as integers (1-12).

Our database has a table named with the following format:

Example Input:

The desired output of this query is a table similar to the following one:

Example Output:

Answer:

The PostgreSQL statement above uses the clause, along with the aggregate function to group the rows by month and product_id, then calculate the average rating for each group. The function is used to extract the month from the date of the review. The result is the monthly average rating for each product.

p.s. Window functions show up super frequently during SQL interviews, so practice the 27+ window function questions on DataLemur

SQL Question 2: Filteration of 'customers' based on specific conditions

You are a data analyst at NetApp. Your task is to identify the customers who are using a certain storage solution (say 'FlexPod'), and have a data usage more than the average.

We want to see the output in the form of a simple customer list which shows customers' names, their storage solution types and data usage, but only for those customers who match the said conditions.

Example Input:

Example Input:

Example Output:

Answer:

In the SQL query above, we are using a SELECT statement combined with WHERE to filter out the relevant customers. We are using a join here to get the average value from a different table. We're looking at all customers('c') who use the 'FlexPod' service and their data usage is greater than the average('a').

SQL Question 3: What does / SQL commands do?

The / operator is used to remove to return all rows from the first SELECT statement that are not returned by the second SELECT statement.

Note that is available in PostgreSQL and SQL Server, while MINUS is available in MySQL and Oracle (but don't worry about knowing which DBMS supports which exact commands since NetApp interviewers aren't trying to trip you up on memorizing SQL syntax).

For a tangible example of in PostgreSQL, suppose you were doing an HR Analytics project for NetApp, and had access to NetApp's contractors and employees data. Assume that some employees were previously contractors, and vice versa, and thus would show up in both tables.

You could use operator to find all contractors who never were a employee using this query:

SQL Question 4: Calculate the Average Storage Space Used Per User

As a data analyst at NetApp, a global cloud-led, data-centric software company. You have been asked to determine the average amount of storage space used per user. NetApp wants this information to understand the storage consumption patterns and may utilize the insights to optimize their storage offerings. You are provided with two tables named and , where the table stores information about the users and the table stores information about the storage space used by each user on a particular date.

Example Input:

Example Input:

Answer:

In the provided SQL query, we are calculating the average of storage used for each user. This is achieved by joining the ‘users’ and ‘storage’ tables on and then grouping by . The average function is then used on to get the average storage used by each user in GB.

To practice a very similar question try this interactive Amazon Maximize Prime Item Inventory Question which is similar for calculating average resource utilization or this Amazon Server Utilization Time Question which is similar for calculating total resource usage.

SQL Question 5: What is a self-join?

A self-join is a type of JOIN where a table is joined to itself. To execute a self-join, you must include the table name twice in the FROM clause and assign a different alias to each instance. You can then join the two copies of the table using a JOIN clause, and use a WHERE clause to specify the relationship between the rows.

For example, say you had website visitor data for NetApp, exported from the company's Google Analytics account. In support of the web-dev team, you had to analyze pairs of pages for UX or navigational issues. As part of that analysis, you wanted to generate all pairs of URLs, but needed to avoid pairs where both the URLs were the same since that's not a valid pair.

The self-join query would like the following:

This query returns the url of each page () along with the url of the page that referred to it (). The self-join is performed using the field, which specifies the id of the page that referred the visitor to the current page, and avoids any pages that referred themself (aka data anomalies).

SQL Question 6: Average Sales Per Customer

NetApp, a company that provides hybrid cloud data services and data management, has a table named 'sales'. Each row in the sales table represents a purchase made by a customer. NetApp wants to know the average sales amount for each customer.

The 'sales' table has the following schema:

Example Input:

NetApp would like to see this information as a table with the customer_ids and their corresponding average sales amount.

Example Output:

Answer:

In this query, we are using the AVG aggregate function to calculate the average sale_amount for each customer. We group by customer_id to get the desired average for each individual customer. If a customer made more than one purchase, this will calculate their average spent amount.

SQL Question 7: What are the ACID properties in a DBMS?

A DBMS (database management system), in order to ensure transactions are relaible and correct, tries to mantain the following ACID properties: Atomicity, Consistency, Isolation, and Durability

Here is what each of the ACID properties stands for:

Atomicity: ensures that a transaction is either completed in its entirety, or not completed at all. If a transaction fails halfway, the database does a rollback on the commit.

Consistency: ensures that a transaction will only be completed if adheres to the constraints defined in the database of the DB.

Isolation: ensures that concurrent transactions are isolated from each one another, so that the changes made by one transaction cannot be seen by a 2nd transaction until the 1st transaction is done.

**Durability: ** ensures that once a transaction has been committed, the database permanently stores the results in the DB.

As you can see, it's pretty important for NetApp's data systems to be ACID compliant, else they'll be a big problem for their customers!

SQL Question 8: Customer Email Pattern Search

As a key player in the data management and cloud storage industry, NetApp often needs to target customers based on their email providers. Assume you are given a customer table, , which consists of various fields including customer's name, and email. Your task is to write a SQL query that would help NetApp to filter and find out all customers who have an email provided by 'gmail.com'.

Here's an example of the tables for this problem:

Example Input:

Expected Output:

Answer:

The following PostgreSQL query will solve the problem:

In this query, we are selecting all columns from the table with the clause that filters the records which have 'gmail.com' in their field. The percent symbol used in the query is a wildcard character which matches any sequence of characters.

Remember that SQL is case insensitive but some database systems like PostgreSQL are case sensitive depending on the specific configuration. If case sensitivity is an issue, you might need to convert all data to lower case using the function before comparing. The updated query would look something like this:

SQL Question 9: Average Revenue Per Customer

For NetApp, a company that specializes in data storage and management, one important question could be to determine the average revenue per customer. The task is to generate a report that gives the average purchase price per customer. Join two tables: that records all customer information and which gives details about all purchases.

Example Input:

Example Input:

Answer:

Here's a PostgreSQL query for the problem:

Explanation:

This query joins the and tables on the field which is common to both. The function is used to calculate the average price of all purchases by each customer. The clause is used to break down the result for each customer.

Because joins come up so often during SQL interviews, try an interactive SQL join question from Spotify:

SQL Question 10: How does a cross join differ from a natural join?

A cross join is a type of JOIN operation in SQL that creates a new table by combining each row from the first table with every row from the second table. It is also known as a cartesian join.

For example, say you worked on the Marketing Analytics team at NetApp, and needed to understand what advertising copy (text) goes best with what advertising creative (the photo that gets posted with the advertisement copy).

Here is an example of a cross-join between a table of ad_copy and a table of ad_creative:

A natural join, on the other hand, is a type of JOIN that combines rows from two or more tables based on their common columns. It is called a "natural" join because it is based on the natural relationship that exists between the common columns in the tables being joined.

For an example of each one, say you had sales data exported from NetApp's Salesforce CRM stored in a datawarehouse which had two tables: and .

An (which is a type of natural join) combines the two tables on the common

This query will return rows from the sales and tables that have matching customer id values. Only rows with matching values will be included in the results.

One main difference between cross joins and natural joins is that cross joins do not require any common columns between the tables being joined, while natural joins do. Another difference is that cross joins can create very large tables if the input tables have a large number of rows, while natural joins will only return a table with the number of rows equal to the number of matching rows in the input tables.

SQL Question 11: Evaluate Company Sales Performance

Given the table, write a PostgreSQL query to calculate the average sales amount per product, rounded to the nearest whole number. Additionally, calculate the square root of total sales for each product, and compute the modulus of total sales with the product_id. The table contains the following data:

Example Input:

Here's the SQL query needed:

Answer:

This query first groups the data by using the clause. Then for each group, it calculates the average sales amount () and rounds it to the nearest whole number using . It also calculates the square root of total sales amount for each product using . Lastly, it computes the modulus with sum of sales and the using the function.

To practice a very similar question try this interactive Amazon Highest-Grossing Items Question which is similar for calculating metrics on product sales or this Alibaba Compressed Mean Question which is similar for applying mathematical operations on sales data.

NetApp SQL Interview Tips

Assuming that you've already got basic SQL skills, the next best tip we have to prepare for the NetApp SQL interview is to solve as many practice SQL interview questions as you can! Besides solving the above NetApp SQL interview questions, you should also solve the 200+ SQL exercises on DataLemur which come from companies like Google, Facebook, Microsoft and Amazon.

Each exercise has hints to guide you, full answers and most importantly, there's an interactive SQL code editor so you can instantly run your query and have it executed.

To prep for the NetApp SQL interview it is also wise to solve SQL questions from other tech companies like:

• Pure Storage SQL questions

• Dell SQL questions

• HPE SQL questions

• IBM SQL questions

However, if your SQL skills are weak, don't worry about going right into solving questions – improve your SQL foundations with this DataLemur SQL tutorial.

This tutorial covers SQL concepts such as UNION vs. joins and creating pairs via SELF-JOINs – both of these pop up routinely in NetApp SQL assessments.

NetApp Data Science Interview Tips

What Do NetApp Data Science Interviews Cover?

Beyond writing SQL queries, the other types of problems to practice for the NetApp Data Science Interview are:

• Probability & Statistics Questions
• Python or R Programming Questions
• Open-Ended Data Case Studies
• ML Modelling Questions
• Behavioral Interview Questions

How To Prepare for NetApp Data Science Interviews?

To prepare for NetApp Data Science interviews read the book Ace the Data Science Interview because it's got:

• 201 interview questions sourced from FAANG, tech startups, and Wall Street
• a crash course on Python, SQL & ML
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