# 10 Brunswick Corporation SQL Interview Questions (Updated 2024)

Updated on

June 30, 2024

[Brunswick Corporation](https://www.Brunswick Corporation.com) employees use SQL often for analyzing customer boat usage trends and optimizing inventory based on sales data. That's the reason behind why Brunswick Corporation almost always asks SQL questions in interviews for Data Science, Analytics, and & Data Engineering jobs.

Thus, to help you practice, we've curated 10 Brunswick Corporation SQL interview questions – can you solve them?

## 10 Brunswick Corporation SQL Interview Questions

### SQL Question 1: Identify Top Product Purchasing Customers for Brunswick Corporation

Brunswick Corporation is a leading global designer, manufacturer and marketer of recreation products including marine engines, boats, fitness equipment, and billiards. They are interested in identifying their "whale" customers, or the customers who frequently purchase their products. They would like to know who are the top 10 customers who made the highest total purchases in the past year.

For this purpose, they have two main tables: and .

The table contains information about each customer. Here's some sample data:

The table contains information about each purchase made by the customers. Here's some sample data:

Using this data, write a SQL query that sorts customers by the total amount of purchases they have made in the past year (from today's date), and returns the top 10 customers with the highest total purchases. Please consider only direct purchases made by the customers for this analysis, i.e., discard any indirect purchases made through any third parties.

This query joins the and tables on the column, sums up the total amount of purchases made by each customer in the past year, and then sorts the customers by their total purchases in descending order. Finally, it returns the top 10 customers.

To practice a similar power-user data analysis problem question on DataLemur's free interactive coding environment, try this recently asked Microsoft SQL interview question:

### SQL Question 2: 2nd Largest Salary

Given a table of Brunswick Corporation employee salary information, write a SQL query to find the 2nd highest salary at the company.

#### Brunswick Corporation Example Input:

employee_idsalary
12500
2800
31000
41200

#### Example Output:

second_highest_salary
1200

Write a SQL query for this problem and run your code right in the browser:

You can find a step-by-step solution here: 2nd Highest Salary.

### SQL Question 3: What's the difference between a unique and non-unique index?

While both types of indexes improve the performance of SQL queries by providing a faster way to lookup rows of data, a unique index enforces the uniqueness of the indexed columns, meaning that no duplicate values are allowed in the indexed columns. On the other hand, a non-unique index allows duplicate values in the indexed columns.

Here is an example of a unique index on the column of a table of Brunswick Corporation employees:

This index would ensure that no two Brunswick Corporation employees have the same , which could be used as a unique identifier for each employee.

Here is an example of a non-unique index on the column of the same table:

This index would not enforce uniqueness, but it could be used to improve the performance of queries that filter or sort the data based on the column. For example, if you want to retrieve all employees who were Data Analysts, the database can use the index to quickly locate and retrieve the desired records without having to search through all the employees.

### SQL Question 4: Calculate the Average Monthly Sales of Each Boat Model

Brunswick Corporation is an American corporation that has been active in a variety of fields. Though they are known for their bowling products, one of their major revenue sources is the marine sector. Suppose you are given a dataset for Brunswick Corporation's monthly boat sales analysis. The dataset includes the model of the boat, the month the boat was sold, and the revenue generated from that sale. Write a SQL query using PostgreSQL that calculates the average sales per month for each model of boat.

##### Example Input:
sale_idmodel_idsell_daterevenue
10011000012022-01-156000
10021000022022-02-088000
10031000012022-01-285500
10041000022022-03-158500
10051000032022-02-187000
10061000012022-03-226200
10071000032022-01-107500

This query first uses the function to get the month from the field. Then it uses the window function to calculate the average revenue for each boat model per month. The clause is used to specify how the window will be divided for the calculation - in this case, it's divided by boat model and month. Finally, The clause is used to order the result first by month and then by model. This makes it easier to follow the average monthly sales for each boat model.

To solve another window function question on DataLemur's free interactive coding environment, try this Google SQL Interview Question:

### SQL Question 5: What is a foreign key?

A foreign key is a field in a database table that links to the primary key of another table, establishing a connection between the two tables. For example, let's analyze Brunswick Corporation's Google Ads campaigns data:

:

+------------+------------+------------+------------+ | ad_id | campaign_id| keyword | click_count| +------------+------------+------------+------------+ | 1 | 201 | Brunswick Corporation reviews | 120 | | 2 | 202 | Brunswick Corporation pricing | 150 | | 3 | 101 | buy Brunswick Corporation | 65 | | 4 | 101 | Brunswick Corporation alternatives | 135 | +------------+------------+------------+------------+

is a foreign key that connects to the of the corresponding Google Ads campaign. This establishes a relationship between the ads and their campaigns, enabling easy querying to find which ads belong to a specific campaign or which campaigns a specific ad belongs to.

The table may also have multiple foreign keys that reference primary keys in other tables. For example, and foreign keys could be used to link each ad to its ad group and the Google Ads account that the campaigns belong to, respectively.

### SQL Question 6: Calculate the Average Production Time for Different Boat Models

Brunswick Corporation is a global manufacturer in the leisure boating industry. In order to keep optimizing its production process, the production department wants to track how long it takes on average to build different types of boats. Create a SQL query to find the average production time for each boat model in their production line.

Please make use of the tables 'Production' and 'BoatModels':

##### Example Input:
production_idboat_model_idstart_dateend_date
1A12022-01-012022-01-15
2B12022-01-062022-01-21
3A12022-01-162022-02-01
4C12022-01-202022-02-02
5B12022-01-222022-02-05
##### Example Input:
boat_model_idboat_model_name
A1Luxury Yacht
B1Speedboat
C1Family Cruiser
##### Example Output:
boat_model_nameaverage_production_time
Luxury Yacht15.5
Speedboat15.0
Family Cruiser13.0

This query joins the 'Production' and 'BoatModels' tables on the 'boat_model_id' field. It then groups the joined tables by the name of the boat model. For each group, it calculates the average production time in days by subtracting the start date from the end date and averaging over all records in the group.

To practice a very similar question try this interactive Tesla Unfinished Parts Question which is similar for calculating production metrics or this Amazon Server Utilization Time Question which is similar for Calculating average time per product.

### SQL Question 7: How does and differ?

The clause works similarly to the clause, but it is used to filter the groups of rows created by the clause rather than the rows of the table themselves.

For example, say you were analyzing Brunswick Corporation sales data:

This query retrieves the total sales for all products in each region, and uses the clause to only sales made after January 1, 2023. The rows are then grouped by region and the clause filters the groups to include only those with total sales greater than \$500k.

### SQL Question 8: Click-through Rate for Brunswick Corporation's Digital Ads

As a Data Analyst at Brunswick Corporation, you're tasked to analyze the effectiveness of online advertising campaigns. Specifically, the marketing team wants to know the click-through rate (CTR) for every ad campaign over the past month, defined as the number of users who clicked on an ad divided by the number of times the ad was shown. Given the data on ad impressions and ad clicks, write a SQL query to solve this problem.

Sample data:

##### Example Input:
1A06/02/2022 00:05:00
2B06/02/2022 00:10:00
3A06/04/2022 00:15:00
4A06/04/2022 00:20:00
5C06/04/2022 00:25:00
##### Example Input:
1A06/02/2022 00:06:00
2B06/02/2022 00:11:00
3A06/04/2022 00:16:00
4B06/04/2022 00:21:00

This SQL query basically joins the and tables on through a LEFT JOIN operation. By doing this, the query ensures that all the ad ids from (even those for which there were no clicks) are included in the final dataset.

Then, it groups the joined tables by , essentially creating subsets of the data for each ad. Within these subsets, it calculates the click-through rate as the number of clicks for each ad divided by the number of impressions for the same ad. The CAST() function is used to convert the integer result of the count operation to float which allows one to perform the division and get a decimal value for the click-through rate.

To solve a similar problem on DataLemur's free interactive SQL code editor, try this Meta SQL interview question:

Take a look at Brunswick Corporation's annual reports and see how they have performed over the years.

### SQL Question 9: Find the Average Selling Price per Category

Brunswick Corporation deals in lifestyle brands that include the manufacture of boats, marine engines, fitness equipment, active recreation products. For this question, imagine you're working with a database table that tracks all of the Corporation's sales.

#### Here's the problem:

Determine the average selling price of each category of the products for the year 2022.

The table has six columns:

• (the unique identifier of each sale)
• (the unique identifier of each product)
• (the category of each product: boat, engine, fitness equipment, or active recreation)
• (the date of sale, stored as a TIMESTAMP)
• (the price of a single product unit)
• (the number of units per sale)

The table might look like this:

##### Example Input:
sale_idproduct_idcategorysale_dateunit_pricequantity
1012001Boat01/15/2022 00:00:00150002
1023001Engine02/18/2022 00:00:0045001
1034001Fitness Equipment03/10/2022 00:00:0025003
1045001Active Recreation04/20/2022 00:00:0010005
1052002Boat05/15/2022 00:00:00165001

#### Your goal is to write a SQL query that returns a table with two columns:

For example, the output might look something like this:

##### Example Output:
categoryaverage_sale_price
Boat15750
Engine4500
Fitness Equipment2500
Active Recreation1000

Benefitting from PostgreSQL, we can write the SQL for this question like so:

In this query, EXTRACT function is used to get the year from the sale_date column. Then we needed to average the unit_price for each product category, which can be done using the AVG function from SQL, grouped by category. This query outputs a single row for each category, with the corresponding average selling price for 2022.

### SQL Question 10: Could you provide a list of the join types in SQL and explain what each one does?

In SQL, a join is used to combine rows from different tables based on a shared key or set of keys, resulting in a single merged table of data.

There are four distinct types of JOINs: , , , and .

(INNER) JOIN: Retrieves records that have matching values in both tables involved in the join.

LEFT (OUTER) JOIN: Retrieves all the records/rows from the left and the matched records/rows from the right table.

RIGHT (OUTER) JOIN: Retrieves all the records/rows from the right and the matched records/rows from the left table.

FULL (OUTER) JOIN: Retrieves all the records where there is a match in either the left or right table.

### How To Prepare for the Brunswick Corporation SQL Interview

The best way to prepare for a Brunswick Corporation SQL interview is to practice, practice, practice. Besides solving the above Brunswick Corporation SQL interview questions, you should also solve the 200+ DataLemur SQL Interview Questions which come from companies like FAANG and tech startups.

Each SQL question has hints to guide you, detailed solutions and most importantly, there is an online SQL code editor so you can right in the browser run your SQL query and have it executed.

To prep for the Brunswick Corporation SQL interview you can also be a great idea to practice SQL questions from other automotive companies like:

In case your SQL coding skills are weak, forget about diving straight into solving questions – strengthen your SQL foundations with this free SQL tutorial.

This tutorial covers things like LEAD/LAG and filtering groups with HAVING – both of these come up routinely in SQL interviews at Brunswick Corporation.

### Brunswick Corporation Data Science Interview Tips

#### What Do Brunswick Corporation Data Science Interviews Cover?

In addition to SQL query questions, the other types of problems to practice for the Brunswick Corporation Data Science Interview are:

• Statistics and Probability Questions
• Python or R Programming Questions
• Data Case Study Questions
• Machine Learning and Predictive Modeling Questions
• Behavioral Based Interview Questions

#### How To Prepare for Brunswick Corporation Data Science Interviews?

I'm sort of biased, but I believe the optimal way to prepare for Brunswick Corporation Data Science interviews is to read the book Ace the Data Science Interview.

The book has 201 interview questions sourced from FAANG tech companies. It also has a crash course covering SQL, Product-Sense & ML. And finally it's vouched for by the data community, which is why it's got over 1000+ 5-star reviews on Amazon.