Top Google Database Interview Questions for Your SQL Interview

Google SQL and database interview questions feature all the time in data science, database management, backend engineering and SQL technical interviews at Google. Given that SQL is used widely in a variety of software jobs, you’re required to know answers to basic SQL interview questions even in software engineering interviews at Google. Most SQL and database interviews typically start off with basic SQL questions, and move medium and query interview questions.

If you’re appearing for a position that requires knowledge of SQL and database management, knowing what type of Google database interview questions are asked is important. To help you prepare, we’ve compiled a list of basic, advanced, and query interview questions.

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Let’s go ahead and look at some Google job interview questions asked at SQL, software engineering, and data-related interviews at Google.

Here’s what we’ll cover:

• Which Interviews Will Ask Google SQL Interview Questions?
• Basic Google Database Interview Questions
• Advanced Google Database Interview Questions
• SQL Query Interview Questions Asked at the Google Interview
• FAQs on Google Database Interview Questions

Which Interviews Will Ask Google SQL Interview Questions?

Google database interview questions, also called Google SQL interview questions, test one’s understanding and ability to manage large-scale databases.

Google database interview questions are typically asked in the following interviews at Google:

• Data Analyst - Data Analyst roles at Google involve working with large and heavy data sets. This means that SQL and database knowledge is extensively evaluated at these interviews.
• Data Science - Data Scientists build and design Machine Learning programs to automate data interaction and decision making. These roles involve leveraging SQL to navigate thick datasets.
• Data Engineers - Data engineering is another profession that involves working with data, naturally requiring the use of SQL and database management concepts to perform data-heavy tasks.  
• SQL developers - As an SQL developer, it is a necessary prerequisite to have strong SQL fundamentals.

Basic Google Database Interview Questions

Basic Google Database interview questions are mostly asked at junior developer and SQL technical interviews at Google.

Let’s look at some common Google database interview questions and answers that feature at these interviews.

Q1. What are Primary Keys in SQL?

Primary keys in SQL are used to identify records in a table. A primary key can be a column or a group of columns that uniquely identify each row in a table. It is important that database tables have primary keys to identify unique table values.

Q2. What are subqueries in SQL?

This is one of the most common Google database interview questions asked in technical interviews.

Subqueries in SQL are queries that are nested within any of the four major SQL statements - SELECT, DELETE, INSERT and UPDATE. Any query nested within a subquery is also considered a subquery in SQL.

Q3. What are constraints in SQL?

Constraints in SQL are a set of rules that are applied to entries in a table. These rules prevent certain data types from being included in tables. Some common SQL constraints include:

• UNIQUE - This constraint is used by the Primary key, and ensures that entries in a column are unique.
• NOT NULL - This constraint prevents null values from being entered into a table
• FOREIGN KEY - This constraint is used to identify a unique row in another table.

Q4. What is Query Optimization in SQL?

Query optimization is the process of choosing the right SQL statements while writing queries to enable quicker outputs and improve system performance.

Q5. Which are the four major subsets of SQL?

The four major subsets of SQL include:

• Data Definition Language
• Data Manipulation Language
• Data Control Language
• Transaction Control Language

Additional Basic Google Database Interview Questions for Practice

1. What are Joins in SQL?
2. What is the difference between TRUNCATE and DELETE statements in SQL?
3. Differentiate between a Relational Database Management System and a normal Database Management System.
4. What do you understand about Action Queries in SQL?
5. Explain the role of Indexes in Database management
6. What are the fundamental commands used in SQL?

Advanced Google Database Interview Questions

Advanced Google database interview questions primarily feature in interviews for data scientists, full stack developers, and data engineers.

Below are some advanced Google database interview questions to give you an idea about the type of questions to expect at your interview.

1. How do you create Indexes in SQL?
2. Explain the differences between Clustered and Non-Clustered Indexes
3. What do you understand about Collation Sensitivity?
4. How do you change the name of a column in SQL?
5. Explain the process of copying the contents of one table to another table.
6. What do you understand about aggregate functions in SQL?
7. What are Scalar functions in SQL? Which are some important Scalar functions that are used?
8. What are the different types of Normalization in SQL?
9. Explain stored procedures and the different types of stored procedures in SQL.
10. What do you understand by ACID properties in SQL?

Google Database Interview Questions on SQL Queries

SQL query interview questions are a part of the advanced Google database interview questions. These questions are commonly asked in SQL technical interviews, senior backend engineering interviews, data engineering interviews and data science interviews.

Query interview questions typically involve using SQL queries to retrieve specific information from datasets, mostly in tabular formats. Let’s look at what Google database interview questions on SQL queries look like.

SQL Query interview questions that feature in Google interviews can be classified into the following categories:

• SQL Query Interview Questions on Joins
• Questions on functions, comparison operators, DDL, and more
• SQL Query Interview Questions on Normalization and Commands

Sample Google SQL Query Interview Questions

The tables below contain employee-related information including employee name, department, gender, project type and salaries. Write SQL queries to provide outputs for the questions.

?Table 2:

Following are the Google SQL interview questions (query-related) that you can expect from the above table.

1. Fetch the salary records from the table in ascending order.
2. Write an SQL query to determine which gender has higher average salaries?
3. What query will you use to calculate the average salary of male employees from the table?
4. Write a query to identify which particular project is associated with the highest compensation.
5. Write a query to determine which employee draws the lowest salary.
6. Write a query to determine which employee draws the highest salary from the table.

Practicing these Google database interview questions will stand you in good stead for your next SQL interview at Google.

FAQs on Google Database Interview Questions

Q1. In what type of interviews are you asked Google database interview questions?

Google database interview questions are typically asked in SQL developer interviews, software developer interviews, backend interviews, data science, and data engineering interviews.

Q2. What is the average salary of a Google SQL developer in the US?

The average salary of Google SQL developers in the United States is $87,375 per year.

Q3. Do you need to be a good programmer to ace SQL interviews?

Although programming-related questions aren’t asked at SQL interviews, roles that entail SQL knowledge often demand strong programming skills as well.

Q4. What type of Google SQL interview questions are asked in Google’s technical interviews?

Google SQL interview questions asked in Google’s interviews include basic SQL interview questions, Advanced SQL interview questions, and SQL Query interview questions.

Q5. Are Google Database Interview Questions asked in Python developer interviews?

Yes, if you’re applying to backend engineering, cloud computing and data-related roles (data engineering, data science, data analyst), you can expect basic, advanced, and query SQL interview questions at Google’s technical interviews.

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