# 8 Colgate-Palmolive SQL Interview Questions (Updated 2024)

Updated on

August 11, 2024

Colgate-Palmolive employees write SQL queries for analyzing sales data to predict trends and seasonality, as well as efficiently managing inventory to minimize waste and ensure timely restocking of best-selling products. For this reason, Colgate-Palmolive frequently asks SQL questions during interviews for Data Analyst, Data Science, and BI jobs.

So, to help you study, we've collected 8 Colgate-Palmolive SQL interview questions – able to solve them?

## 8 Colgate-Palmolive SQL Interview Questions

### SQL Question 1: Analyzing Product Ratings Over Time

You are working as a Data Analyst at Colgate-Palmolive. The marketing team needs your help to analyze the customers' reactions to the company's products. They want to know the average number of stars each product receives per month.

You need to write a PostgreSQL query. The query should return the average number of stars for each product per month and should order the result by month and product ID. Assume you have the following table that customers fill out after purchasing a product:

##### Example:
review_iduser_idsubmit_dateproduct_idstars
1465801/04/2021354
2984601/25/2021215
3245802/11/2021353
4638502/22/2021212
5894703/14/2021355
6362504/09/2021211
7243605/13/2021354
8495806/18/2021213
9374207/24/2021352
1086858/29/2021214

This SQL query first extracts the month from the using the function, gets the and calculates the average of users gave for every product monthly. The clause is used to divided data into groups that share the same values in specified columns here month and . Finally the result is ordered by month and product_id.

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

### SQL Question 2: 2nd Largest Salary

Assume you had a table of Colgate-Palmolive employee salary data. Write a SQL query to find the 2nd highest salary amongst all the .

#### Colgate-Palmolive Example Input:

employee_idsalary
12500
2800
31000
41200

#### Example Output:

second_highest_salary
1200

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

You can find a detailed solution here: 2nd Highest Salary.

### SQL Question 3: What are the various forms of normalization?

Normalization is the process of organizing fields and tables of a database to minimize redundancy and dependency. While there are technically 5 levels (normal forms), the 3 most important normal forms you need to know about for SQL interviews at Colgate-Palmolive are:

1. First Normal Form (1NF): This should fix remove a table's duplicate columns. Also, each column should contain only a single value (no lists or containers of data), and finally each row of table should have a unique identifier as well.

2. Second Normal Form (2NF): A table is in its second normal form if it meets all requirements of the first normal form and places the subsets of columns in separate tables. The relationships between tables are created using primary/foreign keys.

3. Third Normal Form (3NF): The table should be in the second normal form. There should be no dependency on another non-key attribute (meaning a primary key should be the only thing required to identify the row).

### SQL Question 4: Analyzing Product Sales and Customer Feedback

The Colgate-Palmolive company is interested in understanding the relationship between their product sales and customer reviews. Your task is to design a database that can capture this information and then write a query that can calculate the total sales and average review rating for each product within a given month.

Consider the following tables are in the Colgate-Palmolive company's database:

##### Example Input:
sale_idproduct_idsale_datequantity
1015000106/05/2022150
2026985206/10/2022300
3035000106/15/2022250
4046985207/20/2022500
5055500007/25/2022200
##### Example Input:
review_idsubmit_dateproduct_idstars
617106/08/2022 00:00:00500014
780206/10/2022 00:00:00698524
529306/18/2022 00:00:00500013
635207/26/2022 00:00:00698523
451707/05/2022 00:00:00550002

This query extracts the month from the sales date and review submission date, then groups the sales and reviews by the month and product id. It calculates the total quantity of each product sold and the average review rating for each product within each month. The results can help Colgate-Palmolive understand how product sales and customer reviews are related.

### SQL Question 5: Why would it make sense to denormalize a database?

Database denormalization is when you add redundancy to a database, and break typical normalization rules (specified by 1st, 2nd, 3rd normal forms). There's a few reasons to denormalize a database:

• Improved performance: Denormalization often reduces the the number of costly join operations that are needed to retrieve data. This is helpful when the database is being used for OLAP (Online Analytical Processing) use cases, as joins can be expensive and slow.

• Simplification: Denormalization can also be used to simplify the design of a database by reducing the number of tables and relationships that need to be managed. This can make it easier to understand and maintain the database.

• Ease of use: Denormalization can also make it easier for users to work with a database by providing them with a more intuitive and straightforward data model.

While denormalization can be a useful tool for improving performance and scalability, it's important to keep in mind that it can make update and delete operations more complex. This is because denormalization can create data duplicates, which can make it harder to maintain data integrity. So, to avoid any headaches, it's a good idea to start with a well-normalized database design and then consider denormalization only if it's absolutely necessary for your specific performance and scalability needs. In other words, denormalization can be a bit of a wild card, so it's best to handle it with care!

### SQL Question 6: Find the Average of Monthly Sales Volume for A Specific Product of Colgate-Palmolive

As a data analyst at Colgate-Palmolive, you are tasked to track the monthly sales volume of product items. You are specifically interested in knowing the average sales volume of Colgate toothpaste per month for the year 2022.

##### Example Input:
sales_idproduct_namesales_datequantity
1209Colgate Toothpaste01/15/2022 00:00:00400
1011Colgate Toothpaste01/30/2022 00:00:00340
1730Colgate Toothpaste02/14/2022 00:00:00560
1098Colgate Toothpaste02/26/2022 00:00:00680
2019Colgate Toothpaste03/13/2022 00:00:00320
1928Palmolive Dish Soap01/14/2022 00:00:00330
1702Palmolive Dish Soap01/30/2022 00:00:00290
##### Example Output:
monthproduct_nameavg_sales_volume
1Colgate Toothpaste370
2Colgate Toothpaste620
3Colgate Toothpaste320

This query extracts the month from the sale date, groups by this month and the product name, averages the quantity (which represents the sales volume), and filters for only 'Colgate Toothpaste'. The results are then ordered by month for easy viewing.

To practice a very similar question try this interactive Facebook Active User Retention Question which is similar for tracking monthly data or this Amazon Average Review Ratings Question which is similar for calculating average on monthly basis.

### SQL Question 7: What are the similarities and differences between a clustered and non-clustered index?

Here's an example of a clustered index on the column of a table of Colgate-Palmolive payments table:

This creates a clustered index on the column, which will determine the physical order of the data rows in the table.

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

This will create a non-clustered index on the column, which will not affect the physical order of the data rows in the table.

In terms of query performance, a clustered index is usually faster for searches that return a large number of records, while a non-clustered index is faster for searches that return a small number of records. However, updates to a clustered index are slower, as they require the data rows to be physically rearranged, while updates to a non-clustered index are faster, as they only require the index data structure to be updated. Sure, let's begin with defining a SQL click-through rate problem:

### SQL Question 8: Analyzing Click-through Rates for Colgate-Palmolive's Marketing Campaigns

Your job is to analyze the performance of Colgate-Palmolive's marketing campaigns, specifically looking at the click-through rates of their digital ads. You're given two datasets: one contains information about each ad campaign (an table) and the other contains data each user's interaction with the ad (a table).

For this task, your aim is to calculate the click-through-rate (CTR) for each ad campaign, which is defined as the total number of clicks that an ad receives divided by the total number viewers of that ad (all multiplied by 100 to get a percentage).

Here are sample tables for the and datasets:

##### Example Input:
111Fresh Breath18-2420000
222Bright Smile35-4418000
333Glowing Skin25-3415000
##### Example Input:
123456111user107/01/2022 12:00:00
987654222user207/01/2022 12:01:00
234567111user307/01/2022 12:02:00
876543333user107/01/2022 12:03:00
345678111user407/01/2022 12:04:00

You can solve this problem using a subquery to count the amount of clicks for each ad, and then joining this with the table to get the final click-through rates. Here's one way to write the SQL query in PostgreSQL:

This would output the , the , the total amount of clicks for each ad, the total amount of views, and the calculated click-through rate. is used to ensure that ads with no clicks have their total clicks set to zero instead of NULL.

To practice a similar SQL interview question on DataLemur's free online SQL code editor, attempt this Meta SQL interview question:

### Colgate-Palmolive SQL Interview Tips

Assuming that you've already got basic SQL skills, the next best tip we have to prepare for the Colgate-Palmolive SQL interview is to solve as many practice SQL interview questions as you can! Besides solving the above Colgate-Palmolive SQL interview questions, you should also solve the 200+ SQL questions from real Data Science & Analytics interviews which come from companies like tech companies and consumer good companies like Colgate-Palmolive.

Each SQL question has hints to guide you, full answers and crucially, there's an interactive coding environment so you can right in the browser run your SQL query answer and have it checked.

To prep for the Colgate-Palmolive SQL interview it is also useful to practice SQL problems from other consumer good companies like:

In case your SQL foundations are weak, don't worry about jumping right into solving questions – go learn SQL with this DataLemur SQL Tutorial.

This tutorial covers SQL topics like filtering data with boolean operators and filtering data with WHERE – both of these come up often during SQL job interviews at Colgate-Palmolive.

### Colgate-Palmolive Data Science Interview Tips

#### What Do Colgate-Palmolive Data Science Interviews Cover?

In addition to SQL interview questions, the other topics to prepare for the Colgate-Palmolive Data Science Interview are:

#### How To Prepare for Colgate-Palmolive Data Science Interviews?

To prepare for the Colgate-Palmolive Data Science interview make sure you have a deep understanding of the company's values and mission – this will be important for acing the behavioral interview. For technical interviews prepare by reading Ace the Data Science Interview. The book's got: