# 11 Teledyne SQL Interview Questions (Updated 2024)

Updated on

December 7, 2023

At Teledyne Technologies, SQL is used often for analyzing large datasets from aerospace and defense industries, and managing sensor-derived data acquired through oceanographic monitoring equipment. Unsurprisingly this is why Teledyne almost always evaluates jobseekers on SQL problems during interviews for Data Science, Analytics, and & Data Engineering jobs.

So, if you want to ace the SQL Interview, we've curated 11 Teledyne Technologies SQL interview questions – how many can you solve?

## 11 Teledyne Technologies SQL Interview Questions

### SQL Question 1: Sales and Commissions Analysis

As an analyst at Teledyne Technologies, you have been given a task to analyze the sales data in order to compute total sales value and find out top performing salespeople based on commissions earned.

Teledyne has numerous departments that manufacture different industrial, instrumentation, aerospace and defense electronics. Employees earn different commissions on products depending upon the departments.

Given the sales department level data (each record represents a transaction - an employee selling a product), you are to generate a SQL query to compute the total revenue and commissions earned by each employee.

The sales dataset looks like this:

##### Example Input:
transaction_idemployee_idproduct_idquantitysale_pricecommission_rate
1500110055000.05
2500210132000.07
3500110075000.05
4500310223000.10
5500210112000.07

Using a SQL window function, write a query to compute the total sales value (quantity * sale price) and the total commission (total sales value * commission_rate) for each employee.

##### Example Output:
employee_idsales_valuecommission
50016000300
500280056
500360060

#### Answer:

With this SQL query, the total sales value and total commission earned by each employee are calculated using the SUM window function by partitioning over each employee_id. The result is a list of employees along with the total sales value and commissions they've earned.

To solve a related window function SQL problem on DataLemur's free interactive coding environment, solve this Amazon BI Engineer interview question:

### SQL Question 2: Analyzing Sales and Inventory for Teledyne

Teledyne is a large provider of sophisticated electronic components, instruments, and communication products. They often need to track the status of their sales and inventory. They store their data in two tables - and .

The table includes information on all the products they have, with columns for product ID (), product name (), and the quantity of the product in stock ().

The table tracks all sales made, with columns for the transaction ID (), the product ID of the item sold (), the quantity sold (), and the date of the sale ().

Write a SQL query to find the names of products () that were sold more than the quantity present in the inventory on any given day. For simplicity, we are not handling inventory restocks.

##### Example Input:
prod_idprod_namequantity
101Component A100
102Instrument B50
103Product C75
##### Example Input:
trans_idprod_idquantitysale_date
20011015006/10/2022
20021026006/10/2022
20031016006/11/2022
20041032006/12/2022
20051021006/12/2022

#### Answer:

This query first aggregates the table to find the total quantity sold for each product. It then joins this with the table on , and selects the product names where the total quantity sold is greater than the quantity in the inventory.

### SQL QUESTION 3: Can you describe a cross-join and its purpose?

A cross-join, also referred to as a cartesian join, is a type of JOIN that returns the cross-product of two tables. In a cross-join, each row from the first table is paired with every row from the second table, resulting in a new table with a row for each possible combination of rows from the two input tables.

For example, say you worked on the Marketing Analytics team at Teledyne, and were tasked to understand what advertising copy (text) goes best with what advertising creative (the photo that gets used along with the text copy).

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

You could this query to generate all possible combinations of ad copy and ad creative to help you create more effective ads for Teledyne. Just be careful: if you had 1,000 rows of ad copy and 1,000 different image creatives, the resulting cross-join would have 1 million rows! As a result, it's important to use cross-joins judiciously, and make sure that you're not generating more data than you need to.

### SQL Question 4: Filter Customer Equipment Purchases

Write a SQL query that will filter the customer records and list out all those customers who have purchased more than 2 pieces of equipment and spent more than \$10,000 in total on their purchases. Assume that the price of each item is the same across every purchase.

Here is the sample input data in markdown-formatted tables:

##### Example Input:
customer_idfirst_namelast_name
1001JohnDoe
1002JaneSmith
1003JimBrown
1004JillJohnson
##### Example Input:
purchase_idcustomer_idpurchase_dateequipment_idprice
8001100101/08/202220001\$5000
8002100105/10/202220002\$5000
8003100120/09/202220003\$5000
8004100207/10/202220002\$4000
8005100230/11/202220003\$4000
8006100301/08/202220001\$2500
8007100305/10/202220002\$2500
8008100320/12/202220003\$2500
8009100420/12/202220003\$4000

#### Answer:

This query joins the and tables on the field. It groups the results by , , and (which ensures that each group represents a unique customer) and uses the clause to filter out the groups (i.e., customers) who have made more than 2 equipment purchases and spent more than \$10,000 in total.

### SQL QUESTION 5: 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.

### SQL Question 6: Average Cost of Teledyne's Contracts

Imagine that you have been hired as a Data Analyst at Teledyne and your first task is to find the average contract cost per sector for the year 2021.

#### The table is structured as follows:

contract_idsectorcontract_datecost
101Defense01/05/202120000
102Space01/14/202135000
103Defense01/27/202115000
104Marine02/10/202140000
105Space02/22/202131000

sectoravg_cost
Defense17500
Space33000
Marine40000

#### Answer:

This query will return the average cost () for each sector. The clause is used to filter only those contracts that were signed in the year 2021. The statement will then group these records by sector. Finally, the function is used to calculate the average cost of the contracts in each sector.

To practice a very similar question try this interactive Amazon Highest-Grossing Items Question which is similar for requiring calculations per category or this Amazon Average Review Ratings Question which is similar for needing average calculations for a timespan.

### SQL QUESTION 7: What do foreign key's do?

A foreign key is a column or group of columns in a table that refers to the primary key in another table. The foreign key constraint helps maintain referential integrity between the two tables. The table with the foreign key is called the child table, while the table with the candidate key is called the parent or referenced table.

For example, consider a database with two tables: and customer_idcustomer_idcustomer_id` column in Teledyne customers table.

### SQL Question 8: Clickthrough Conversion Rates for Teledyne

Teledyne usese digital marketing in order to market their products.

Assume that they want to understand the clickthrough rates from their electronic products catalog pages to the "add to cart" action. Teledyne tracks both product views and "add to cart" actions.

Consider the following tables:

Example Input:

view_iduser_idview_dateproduct_id
731252106/08/2022 00:00:0050001
864261206/10/2022 00:00:0069852
862554706/18/2022 00:00:0050001
730551207/26/2022 00:00:0069852
892059807/05/2022 00:00:0069852

Example Input:

action_iduser_idaction_dateproduct_id
220552106/08/2022 00:00:0050001
375261206/10/2022 00:00:0069852
392059807/05/2022 00:00:0069852

Write a SQL query that returns a table indicating the clickthrough conversion rate overall for Teledyne, from product page views to the "add to cart" action.

#### Answer:

This query takes both the page views and add to cart actions. It joins those two tables on the user ID, product ID, and making sure that the product view happened before or at the same time as the add to cart action. Then, it takes the count of successful "add to cart" actions (where there's a matching product page view beforehand) divided by the total product page views to get the clickthrough rate per product. The resulting table is ordered by the highest clickthrough rate.

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

### SQL Question 9: Filter Customer Records with Specific Pattern

You are given access to a database table named representing Teledyne customer data.

Your task is to write a SQL query that can filter all records where the field contains 'gmail' as the domain.

The table is represented as:

##### Example Input:
idfirst_namelast_nameemail
1JohnDoejohn.doe@gmail.com
2JaneSmithjane.smith@yahoo.com
3JimBrownjim.brown@hotmail.com
4JillJohnsonjill.johnson@gmail.com
5JoeDavisjoe.davis@teledyne.com
##### Example Output:
idfirst_namelast_nameemail
1JohnDoejohn.doe@gmail.com
4JillJohnsonjill.johnson@gmail.com

#### Answer:

The SQL query to solve this problem could look like this:

This query uses the SQL keyword to filter all records where the field ends with 'gmail.com'. The '%' character is a wildcard that can match any sequence of characters, so '%gmail.com' matches any string that ends with 'gmail.com'.

### SQL QUESTION 10: What are SQL constraints, and can you give some examples?

In a database, constraints are rules that the DBMS (database management system) follows when performing operations such as inserting, updating, or deleting data.

For example, consider a table of employee records at Teledyne. Some constraints that you might want to implement include:

• NOT NULL: This constraint ensures that certain columns, such as the employee's first and last name, cannot be NULL.
• UNIQUE: This constraint ensures that each employee has a unique employee ID.
• PRIMARY KEY: This constraint combines the NOT NULL and UNIQUE constraints to create a primary key for the employee table. The primary key is a column or set of columns that uniquely identifies each row in the table.
• FOREIGN KEY: This constraint establishes a relationship between the employee table and other tables in the database. For example, you could use a foreign key to link the employee ID to the department ID in a department table to track which department each employee belongs to.
• DEFAULT: This constraint specifies a default value for a column in case no value is specified when a new row is inserted into the table.

### SQL Question 11: Calculate The Products' Weight Differences and Ratios

Teledyne produces specific tech products which have varying weights at different stages of production. The weights are recorded at the beginning and end of the production line. Your task is to create an SQL query that will calculate the absolute difference and ratios of the recorded weights of each product at both stages.

##### Example Input:
production_idproduct_idstart_weightend_weight
0011001500.00505.30
00210021000.00975.10
0031003450.00445.75
00410042000.001999.95
0051005350.00349.65
##### Example Input:
product_idproduct_name
1001Smart Camera
1002AI Processor
1003Wifi Module
1004Secure Router
1005Bluetooth Adapter

#### Answer:

This query joins the table and table together by . Then it calculates the absolute difference and ratio of the and for each product.

Absolute difference is calculated using function and is calculated by dividing by rounded to two decimal places using function.

To practice a very similar question try this interactive Tesla Unfinished Parts Question which is similar for tracking production progress.

p.s. in case this question was tricky, strengthen your SQL foundations with this free SQL tutorial which has 30+ lessons including one on SQL math functions.

### Preparing For The Teledyne SQL Interview

Assuming that you've already got basic SQL skills, the next best tip we have to prepare for the Teledyne SQL interview is to solve as many practice SQL interview questions as you can!

In addition to solving the above Teledyne SQL interview questions, you should also solve the 200+ SQL exercises on DataLemur which come from companies like Microsoft, Google, Amazon, and tech startups.

Each SQL question has multiple hints, full answers and crucially, there is an interactive SQL code editor so you can right in the browser run your SQL query answer and have it checked.

To prep for the Teledyne SQL interview you can also be helpful to practice interview questions from other defense & aerospace contractors like:

However, if your SQL coding skills are weak, don't worry about jumping right into solving questions – strengthen your SQL foundations with this SQL interview tutorial.

This tutorial covers topics including how window functions work and filtering with LIKE – both of which show up routinely during Teledyne SQL interviews.

### Teledyne Technologies Data Science Interview Tips

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

For the Teledyne Data Science Interview, in addition to SQL query questions, the other types of questions which are covered:

• Statistics and Probability Questions
• Python or R Programming Questions
• Product Analytics Questions
• Machine Learning and Predictive Modeling Questions
• Behavioral Interview Questions

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

The best way to prepare for Teledyne Data Science interviews is by reading Ace the Data Science Interview. The book's got:

• 201 Interview Questions from Google, Microsoft & tech startups
• A Crash Course on Stats, ML, & Data Case Studies
• Amazing Reviews (900+ reviews, 4.5-star rating)