8 SAIC SQL Interview Questions (Updated 2024)

At SAIC, SQL is frequently used for analyzing complex defense and intelligence datasets, including geospatial data and surveillance footage. It is also used for managing large-scale data storage within the government contracting sector, such as storing and retrieving classified documents. That is why SAIC often asks SQL questions during interviews for Data Science, Analytics, and & Data Engineering jobs.

So, to help you practice for the SAIC SQL interview, here’s 8 SAIC SQL interview questions in this article.

8 SAIC SQL Interview Questions

SQL Question 1: Identify Top Spending Customers in SAIC

SAIC, a leading technology integrator, keeps track of all the purchases made by its customers. Every purchase includes details such as customer id, purchase id, purchase amount, and purchase date. Your task is to write a SQL query to identify the top 5 customers who have made the highest total purchases in the current year.

Assume we have the following table, .

Example Input:

Answer:

This query first filters the records for the current year using WHERE clause. Then it groups the records by customer_id and sums the purchase_amt for each customer. After calculating the total purchase_amt for each customer, it orders the records in descending order of the total_purchase_amt, and limits the result to the top 5 records. This gives us the top 5 customers who have made the highest total purchases in the current year.

To solve a related customer analytics question on DataLemur's free interactive SQL code editor, try this Microsoft Azure Cloud SQL Interview Question:

SQL Question 2: Employee Salaries Higher Than Their Manager

Suppose there was a table of SAIC employee salary data. Write a SQL query to find the employees who earn more than their own manager.

SAIC Example Input:

Example Output:

This is the output because Olivia Smith earns $8,000, surpassing her manager, William Davis who earns 7,800.

Try this question and run your code right in DataLemur's online SQL environment:

Answer:

First, we perform a SELF-JOIN where we treat the first table () as the managers' table and the second table () as the employees' table. Then we use a clause to filter the results, ensuring we only get employees whose salaries are higher than their manager's salary.

If the code above is confusing, you can find a step-by-step solution with hints here: Employees Earning More Than Managers.

SQL Question 3: What are the three different normal forms?

Normal forms are guidelines that are used to help design a relational database in a way that minimizes redundancy and ensures the integrity of the data. The 3 most commonly use normal forms are the 1st, 2nd, and 3rd normal forms. Here's a brief explanation of each:

• 1st Normal Form (1NF) is all about keeping it simple - each column should only have one value and there should be no repeating groups of data.

• 2nd Normal Form (2NF) is about organization - your database should already be in 1NF and all the non-key columns should depend on the primary key. This means that each non-key column should be completely dependent on the entire primary key, not just part of it.

• 3rd Normal Form (3NF) is about independence - if your database is already in 2NF, then all the non-key columns should not depend on each other. They should be self-sufficient and not rely on other non-key columns.

SQL Question 4: Analyze Average Ratings of Products by Month

Given the table with columns , , , and , write a SQL query to find the average rating for each product every month. Keep in mind that is a datetime field and 'stars' is the rating given by the user to the product.

Example Input:

Example Output:

Answer:

This query first extracts the month from the using the EXTRACT function and groups the data by extracted month and product id. It then averages the for each group to give the monthly average rating for each product.

For more window function practice, solve this Uber SQL Interview Question on DataLemur's interactive coding environment:

SQL Question 5: How would you speed up a slow SQL query?

Here's some strategies that can generally speed up a slow SQL query:

• Only query the columns you actually need
• Index the columns used in the query
• Use the right kind of JOIN (be explicit about inner vs. outer joins)
• Use the right data types (for example INT vs BIGINT can save you disk space and memory)

While there's an entire industry dedicated to database performance tuning , for Data Analyst and Data Science interviews at SAIC, knowing the above basics should be more than enough to ace the SQL interview! Data Engineers on the other hand should know more about the command and understand a bit more about a query-execution plan.

SQL Question 6: Filtering Customer Records

As an SAIC database manager, we have a SQL table and we would like to filter data from our customers' databases based on various conditions. Write an SQL query that returns the customer name, address, and total number of purchased products for customers who live in 'California' and have purchased more than 10 products.

Example Input:

Example Input:

Answer:

This query first joins the and tables on the column. It then applies a filter to only include customers living in 'California'. The results are grouped by customer's first and last name, and the total quantity of their purchased products is calculated. The clause then filters out the customers who purchased less than or equal to 10 products.

SQL Question 7: What are database views, and when would you use them?

A database view is a virtual table that is created based on the results of a SELECT statement, and provides you a customized, read-only version of your data that you can query just like a regular table.

You'd want to use a view for a few reasons:

• views allow you to create a simpler versions of your data based on whose running the query (such as hiding un-important columns/rows from business analysts if they're just random noisy artifricats of your Data Infrastructure pipelines)
• views can help you comply with information security requirements by hiding sensitive data from certain users (important for regulated industries like govermnet and healthcare!)
• views often improve performance for complicated queries by pre-computing the results and saving them in a view (which is often faster than re-executing the original query)... just be careful since static views don't update if the underlying data changes!

SQL Question 8: Customer Order Analysis

Your task is to write a SQL query that calculates the total order amounts for different product categories sold to customers in the department of "Defense & Space" in the last quarter of 2020. You should show the output to the nearest two decimal points.

Below are the sample tables, and :

Table Example:

Table Example:

Answer:

This query joins the and tables on the and filters rows in the table where the order date falls within the last quarter of 2020 and the corresponding department in the table is 'Defense & Space'. It then groups the rows by and calculates the total order amount for each group (here, product category) with a precision of two decimal points.

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

SAIC 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. Beyond just solving the above SAIC SQL interview questions, you should also solve the 200+ SQL exercises on DataLemur which come from companies like Microsoft, Google, and Meta.

Each SQL question has multiple hints, full answers and most importantly, there's an interactive coding environment so you can right in the browser run your query and have it graded.

To prep for the SAIC SQL interview it is also helpful to practice SQL problems from other consulting and professional service companies like:

• Booz Allen SQL questions
• Insight Enterprises SQL questions
• FTI Consulting SQL questions
• Maximus SQL questions

Discover how SAIC is leveraging data and AI to stay ahead of the curve and deliver innovative solutions for their clients!

In case your SQL foundations are weak, don't worry about jumping right into solving questions – improve your SQL foundations with this SQL tutorial for Data Scientists & Analysts.

This tutorial covers topics including CASE/WHEN/ELSE statements and Union vs. UNION ALL – both of these come up often during SQL interviews at SAIC.

SAIC Data Science Interview Tips

What Do SAIC Data Science Interviews Cover?

In addition to SQL interview questions, the other types of questions to practice for the SAIC Data Science Interview include:

• Probability & Statistics Questions
• Coding Questions in Python or R
• Product Metrics Interview Questions
• Machine Learning Questions
• Behavioral Questions based on SAIC cultural values

How To Prepare for SAIC Data Science Interviews?

To prepare for SAIC 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 SQL, Product-Sense & ML
• over 1000+ 5-star reviews on Amazon

Don't forget about the behavioral interview – prepare for that using this guide on acing behavioral interviews.