# 11 Temenos SQL Interview Questions (Updated 2024)

Updated on

March 2, 2024

At Temenos, SQL is typically used for extracting and analyzing financial data, and for generating insights into how banks use Temenos's digital banking products. That's the reason behind why Temenos asks SQL problems in interviews for Data Analytics, Data Science, and Data Engineering jobs.

Thus, to help you study for the Temenos SQL interview, here’s 11 Temenos SQL interview questions – able to answer them all?

## 11 Temenos SQL Interview Questions

### SQL Question 1: Identify High Frequency Banking Customers

The Temenos Company is a software service provider that specializes in banking and finance services. The company's information system is rich with data about the financial transactions of its customers. As part of the company's effort to provide premium service to its most active customers, your task is to write a SQL query to identify the top 'whale' customers - these customers are those who have had the largest total of financial transactions with the bank over the last month.

##### Example Input
transaction_idcustomer_idtransaction_datetransaction_amount
87614232022-09-012000.00
87629872022-09-023000.00
87634232022-09-032500.00
87644262022-09-04400.00
87654232022-09-063000.00
##### Example Output:
customer_idtotal_amount
4237500.00
9873000.00
426400.00

You can use the following SQL query to solve this problem:

This PostgreSQL query does the following:

• Selects the and the sum of for each customer from the table.
• Filters the transactions only to those that occurred in the previous month with the help of function.
• It then groups the results by and orders the result in a descending order of .
• Lastly, using the clause, it restricts the result to top 10 customers having the highest transaction totals which represents our 'whale' customers.

To solve a super-customer analysis question on DataLemur's free interactive coding environment, try this Microsoft SQL Interview problem:

### SQL Question 2: Calculate the Monthly Average Rating for Each Product

As a data analyst at Temenos, your task is to analyze the customer feedback. You have been provided with a dataset consisting of product reviews submitted by users.

The table has the following columns:

• : an integer indicating the unique ID of a review
• : an integer indicating the unique ID of the user who submitted the review
• : a date-time string indicating when the review was submitted
• : an integer indicating the unique ID of the product being rated
• : an integer indication of the number of stars given in the review (out of 5)

You need to write a SQL query which calculates the average given to each for every month. The output will be in descending order by .

##### Example Input:
review_iduser_idsubmit_dateproduct_idstars
61711232022-06-08500014
78022652022-06-10698524
52933622022-06-18500013
111922022-07-26698523
659812022-07-05698522
##### Example Output:
mthproduct_idavg_stars
6698524.00
6500013.50
7698522.50

This query will create a window for each for each month and then calculate the average number of . The answer uses PostgreSQL syntax, specific functions may vary in other SQL types. In real world the query may take a few moments to compute, especially if the database is large.

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

### SQL Question 3: What does it mean to use a UNIQUE constraint in a database?

A UNIQUE constraint ensures that all values in a column are different. It is often used in conjunction with other constraints, such as NOT NULL, to ensure that the data meets certain conditions.

For example, if you had Temenos sales leads data stored in a database, here's some constraints you'd use:

In this example, the UNIQUE constraint is applied to the "email" and "phone" fields to ensure that each Temenos lead has a unique email address and phone number. This helps to ensure the integrity of the data in the database and prevents errors that could occur if two leads had the same email address or phone number.

### SQL Question 4: Average Transaction Size for each Temenos Product

Temenos is a company that specializes in enterprise software for banks and financial services. They offer a range of different products for handling different kinds of financial transactions. For this question, assume you have a table "transactions", where each row represents a transaction done via a Temenos product.

Your task is to write a SQL query that calculates the average transaction amount for each Temenos product.

##### Example Input:
transaction_idproduct_idtransaction_datebank_idtransaction_amount
1234A108/01/2023B00150000
2345B208/02/2023B00245000
3456A108/03/2023B00155000
4567C308/04/2023B00360000
5678B208/05/2023B00250000
##### Example Output:
product_idavg_transaction_amount
A152500
B247500
C360000

This query calculates the average transaction amount for each product by grouping the table by and applying the function to the column for each group. The result is a table with each product and its corresponding average transaction amount.

To practice a very similar question try this interactive Stripe Repeated Payments Question which is similar for transaction-based data analysis or this Amazon Average Review Ratings Question which is similar for averaging grouped product data.

### SQL Question 5: What is the difference between a primary key and a foreign key?

A primary key is a column (or set of columns) in a table that uniquely identifies each row in the table. It cannot contain null values and must be unique across all rows in the table.

A foreign key is a column (or set of columns) in a table that references the primary key of another table. It is used to establish a relationship between the two tables. A foreign key can contain null values, and multiple rows in the referencing table can reference the same row in the referenced table.

For example, consider a database with two tables: and . The Temenos customers table might have a primary key column called , while the Temenos orders table might have a foreign key column called that references the column in the table. This establishes a relationship between the two tables, such that each row in the orders table corresponds to a specific Temenos customer.

### SQL Question 6: Average Balance Per Account Type

The banking software company Temenos tracks customer account information in the table with columns , , (standard, gold, platinum), and .

The task is to write a query that finds the average balance for each account type.

##### Example Input:
account_idcustomer_idaccount_typebalance
1123standard500
2265gold2000
3362standard300
4981platinum5000
5562gold2500
6302gold1900
7419standard600
8327platinum5500
##### Example Output:
account_typeavg_balance
standard466.67
gold2133.33
platinum5250.00

Here is the SQL block containing the answer:

This SQL query groups all accounts by their type and then calculates the average balance within each group. Specifically, the function computes the mean balance of all accounts of the same type.

### SQL Question 7: In SQL, are NULLs treated the same as zero's and blank spaces?

NULLs are NOT the same as zero or blank spaces in SQL. NULLs are used to represent a missing value or the abscence of a value, whereas zero and blank space are legitimate values.

It's important to handle NULLs carefully, because they can mess up your analysis very easily. For example, if you compare a NULL value using the = operator, the result will always be NULL (because just like Drake, nothing be dared compared to NULL). That's why many data analysis in SQL start with removing NULLs using the function.

### SQL Question 8: Find Customers with a Londonderry Address

Temenos runs a global banking software solution and has a significant customer base. The marketing department wishes to target customers based in Londonderry for a new product lunch. Your task is to filter down the customers whose address contains the word 'Londonderry'.

#### Example Input:

371HarryPotterhp@hogwarts.com4 Privet Drive, London
872HermioneGrangerhg@hogwarts.com19 Grimmauld Place, London
5293RonWeasleyrw@hogwarts.comThe Burrow, Ottery St Catchpole
6352HagridRubeushagrid@hogwarts.comHut on the Grounds, Londonderry

#### Example Output:

6352HagridRubeushagrid@hogwarts.comHut on the Grounds, Londonderry

You can use the PostgreSQL keyword in your clause to filter and get the addresses containing 'Londonderry'.

Your SQL code might look like this:

The wildcard matches any number of characters, including zero characters. So by putting wildcards on both sides of 'Londonderry', we can match any address that includes 'Londonderry' in any part of the string.

### SQL Question 9: Analysis of Customers' Software Usage

You are a data analyst at Temenos, a company that creates banking software. You've been asked to analyze customers' software usage patterns in relation to their customer service interactions. You need to create an SQL query that will join the 'customer' and 'customer_service_interactions' tables, group by customer_id, and find the average software log-ins along with the total number of customer service interactions for each customer. Assume there can be multiple interactions and log-ins per day.

##### Example Input:

This SQL query performs left joins on the 'customer' table with the 'software_logins' and 'customer_service_interactions' tables, based on the 'customer_id'. 'COUNT(DISTINCT s.login_date)' is used to calculate the average number of log-ins per customer, and 'COUNT(i.interaction_date)' is used to calculate the total number of interactions per customer. These are all grouped by 'customer_id' to ensure each row of output represents a unique customer.

Because join questions come up routinely during SQL interviews, take a stab at an interactive SQL join question from Spotify:

### SQL Question 10: Can you explain the meaning of database denormalization?

Denormalization is the practice of altering a database schema in a way that breaks the normalization rules (1st, 2nd, 3rd normal forms).

Denormalization is done to improve the performance of the database when it is being used for online analytics processing (OLAP), rather than online transaction processing (OLTP) use cases.

For these OLAP use cases, you're bottleneck frequently is joining multiple tables, but de-normalizing your database cuts these outs.

Denormalization can improve query performance by reducing the number of expensive joins required to retrieve data, but it comes with its own drawbacks too. By adding redundant columns, you incur more data storage costs, and there's need for more complex update and delete operations in order to maintain data integrity across all the duplicated data. Thus, it's important to carefully consider the trade-offs involved before implementing denormalization.

### SQL Question 11: Calculate the Growth Rate

You are given a table of sales data for Temenos company. The data consists of sales amounts for different products, in different months, in different regions. Your task is to write an SQL Query which calculates the month-over-month growth rate for each product in each region. The growth rate should be rounded up to 2 decimal places.

##### Example Input:
sale_idproduct_idregion_idamountmonth
2001111150002021-01
2002111145002021-02
2003111150002021-03
2101222265002021-01
2102222266002021-02
2103222265002021-03
2201333350002021-01
2202333351002021-02
2203333352002021-03
##### Expected Output:
monthproduct_idregion_idgrowth_rate
2021-021111-0.10
2021-0311110.11
2021-0222220.02
2021-032222-0.02
2021-0233330.02
2021-0333330.02

You can calculate the month-over-month growth rate using the window function to compare amounts in each month to the amount in the previous month. Here's how you can do it:

In the above query, the table has the total sales for each product in each region, for each month. The table adds a column for the previous month's total sales. Finally, the growth rate is calculated as (total sales of this month - total_sales of previous_month)/total sales of this month. ROUND function is used to limit the growth rate to 2 decimal places.

To practice a very similar question try this interactive Wayfair Y-on-Y Growth Rate Question which is similar for calculating growth rate using SQL or this Microsoft Teams Power Users Question which is similar for dealing with amounts and identifying top performers.

### Temenos SQL Interview Tips

The best way to prepare for a SQL interview, besides making sure you have strong SQL fundamentals, is to practice a ton of real SQL questions that were asked in recent job interviews. Besides solving the above Temenos SQL interview questions, you should also solve the 200+ DataLemur SQL Interview Questions which come from companies like Microsoft, Google, and Facebook.

Each problem on DataLemur has hints to guide you, full answers and crucially, there is an interactive SQL code editor so you can easily right in the browser your query and have it executed.

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

But if your SQL coding skills are weak, forget about going right into solving questions – improve your SQL foundations with this interactive SQL tutorial.

This tutorial covers SQL concepts such as math functions like CEIL()/FLOOR() and rank window functions – both of these come up often during SQL interviews at Temenos.

### Temenos Data Science Interview Tips

#### What Do Temenos Data Science Interviews Cover?

Besides SQL interview questions, the other types of questions to practice for the Temenos Data Science Interview are:

#### How To Prepare for Temenos Data Science Interviews?

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

• 201 interview questions taken from companies like Google, Tesla, & Goldman Sachs
• a refresher on Python, SQL & ML
• over 900+ reviews on Amazon & 4.5-star rating