Top 25 Amazon SQL Interview Questions and Answers in 2022

The Amazon SQL interview questions cover a broad spectrum of SQL principles. However, some emerge more frequently. Before we begin, it is crucial to know that SQL interview questions at Amazon are not always difficult. Instead, they are aimed at assessing your ability to think critically. It is not simple to ace the Amazon interview. This article will walk you through the top 25 Amazon SQL interview questions.

1. Why Would You Like To Work At Amazon?

Amazon is the largest e-commerce corporation in the world; I have always desired to work there. I have always believed that the sky is the limit, and I have always pushed myself to achieve more than I thought possible. I believe that a job at Amazon will expose me to new challenges and processes that will benefit my career. I would also like to meet your present team of professionals with whom I can exchange ideas and learn. I am confident that Amazon will provide me with the job experience I am currently seeking.

2. What Distinguishes You From Other Applicants For This Job At Amazon?

I have over five years of expertise using SQL in various programs, which gives me confidence in my ability to do the duties competently. In addition to my significant database knowledge, I also hold certifications in data encryption and the SQL programming language. It means I can assist your firm in maintaining its data security while continuing to use it for business purposes.

3. How Do You Acquire The Trust Of Your Coworkers When Starting A New Job Position?

I believe establishing trust is the cornerstone of all personal or professional relationships. I enjoy getting to know my coworkers better when beginning a new position. I believe learning about a coworker’s family demonstrates care and thoughtfulness. I establish credibility by keeping my word and carrying out my commitments. I am dependable and do not bring stress to my team by calling in ill or being late to work. I never speak negatively about others behind their backs and do not engage in nasty office gossip. I believe you may easily acquire someone’s trust by being trustworthy and courteous.

4. How Do You Maintain Your Drive In This Field?

I am intrinsically motivated at all times. External or internal, I am inspired to improve and surpass limitations. A feature that has kept me driven for years is my enjoyment of exceeding my expectations. A component adding to my motivation in this sector is that I comprehend my position in team situations and cannot let my team down. I am confident that working at Amazon will inspire me to work harder.

5. How Well Do You Work When You’Re Part Of A Team?

I realize you value teamwork at Amazon. I want to affirm that I have worked in multiple teams in the past and, as a result, have been able to get along with others and contribute effectively in team settings. I can respect limits, inspire my teammates to achieve their best, and contribute to the team’s overall performance. Thanks to my interpersonal and people abilities, which have served me well throughout my career, I am convinced I will get along with your team.

6. What Is The SQL Language?

SQL is the abbreviation for Structured Query Language. It is the standard language for maintaining relational databases and performing various data manipulation tasks. It is a database language used for creating, deleting, retrieving, and updating database rows, etc. It can also manage structured data consisting of entities (variables) and relations between them.

7. What Exactly Is Amazon’s Database?

Amazon database is one of Amazon Web Services and is a wholly managed petabyte-scale data warehouse service. The database is a relational one. Relational databases are unsuitable for various use cases, particularly those seeking extremely high performance or dynamic scalability. Non-relational databases, or NoSQL, disrupt the paradigm of storing data in tables with columns and rows, allowing for more efficient data distribution and processing. NoSQL manages massive numbers of unstructured or semi-structured data, also known as “big data.” Amazon Database Services such as DynamoDB, RDS, ElastiCache, and RedShift are available.

8. What Is DynamoDB’s Auto-Scaling Feature?

Amazon DynamoDB is a fully managed database utilized by developers and database managers for over a decade. It provides low-latency performance at any scale and simplifies database capacity management significantly. DynamoDB auto scaling only alters provided throughput settings if the demand is elevated (or reduced) for several minutes. Long-term, the Application Auto Scaling goal tracking mechanism aims to maintain target utilization at or around your specified value.

9. Which Of The Four AWS Services For Gathering And Processing E-Commerce Data For Real-Time Analysis Would You Choose?

We may perform real-time analysis on the collected data from our e-commerce transactions by utilizing various Amazon Web Services (AWS) services. I prefer to use DynamoDB to collect and analyze data related to e-commerce for real-time analysis. It is a fully managed NoSQL database service used for any unstructured data and the data acquired from e-commerce websites.

10. What Is A SQL Full OUTER JOIN?

A full outer join is a method for merging tables in which the result contains data from both tables that do not match. Use a FULL OUTER JOIN clause when joining two tables, and you want the result set to include unmatched rows from both tables. The join condition determines matching. If a column in the result table does not include a value, that column contains the null value. The join condition for a full outer join must be either a simple search condition comparing two columns or invocating a cast function with a column name as an argument.

11. What Is The Distinction Between INNER JOIN And OUTER JOIN?

An INNER JOIN is a form of join that returns all rows from both tables when the critical records of one table match the essential records of the other table. This sort of join needed a comparison operator to match rows from the participating tables based on a field or column shared by both tables. Whereas the OUTER JOIN returns all rows from the participating tables that satisfy the criterion, this operation returns rows that do not satisfy the requirement.

12. Could You Please Explain What A View Is?

A view can be considered a subset of a table that is logically kept in a database. It is structured similarly to a real table, with rows and columns. The view contains fields derived from one or more of the underlying real tables. The views themselves do not include any data of their own. They serve two purposes: they can restrict access to the database and disguise the intricacy of the data.

13. What Exactly Is Subquery?

A Subquery is a query that is contained within another query. A subquery is incorporated into a more powerful query. Subqueries are also known as INNER QUERY and NESTED QUERY. They supply the main query, parent or outer query, with data. A subquery is essentially an embedded SELECT statement within the clause of another SQL statement. We can insert subqueries into the SELECT clause, the FROM clause, the WHERE clause, and the HAVING clause of the parent or outer query. The inner query is conducted once before its parent query to convey the inner query’s results to the outer query.

14. What Are SQL Pseudo Columns?

Pseudo Columns are columns that can be recovered by queries but do not exist physically on the table. These are alternative types of variables in high-level programming languages. Here, we can call various bogus columns, and the system will return the desired response. Additionally, we may compare the Pseudo column to functions with no arguments. We must ensure that update, remove, and insert queries cannot be performed on these columns when using pseudo columns. Among the essential Pseudo, Columns are ROWNUM, ROWID, and USER.

15. What Is The Difference Between A Leader Node And A Computer Node?

When a query references user-created tables or system tables, the leader node distributes SQL to compute nodes. A query that refers only to catalog tables (tables with a PG prefix, such as PG TABLE DEF) or no tables executes on the leader node only. The methods designated in the pioneer hub are carried out in a computer node, and data is transmitted. The result is then transmitted back to the pioneer hub before being transmitted to the customer application.

16. Describe The Amazon Relational Database.

Amazon’s relational database is a service that assists users with the operation, alignment, and scalability of an online database within the cloud. It automates administrative operations such as data configuration, hardware provisioning, backups, and maintenance. Amazon’s relational database offers scalable and cost-effective functionality. Automating tasks saves time and allows the user to focus on applications, providing them with high availability, quick performance, compatibility, and security. Several AWS RDS engines are available, including MySQL, Oracle, PostgreSQL, SQL Server, MariaDB, and Amazon Aurora.

17. What Exactly Are The Benefits Of Using SQL Functions?

There are many different applications for SQL functions, including the following:

  • To translate the other forms of data
  • To exert influence over the outcome
  • To perform various computations based on the data.
  • To change individual data items
  • To format numerical values and dates

18. Describe The Benefits And Drawbacks Of The Stores Procedure.

It is possible to utilize Stored Procedures as modular programming, which means that once we generate a procedure, we may save it and recall it at any time. It is one of the primary advantages of using Stored Procedures. It allows for speedier execution, minimizes the network’s traffic, and provides enhanced protection for the data. The primary drawback is that it can only be processed within the database and requires memory space for storage on the database server. It is the only place where we can use it.

19. Describe The Distinction Between SQL And MySQL

There are some distinctions between the two:

  • MySQL AB created MySQL, which is currently owned and managed by the ORACLE Corporation. Unlike SQL, which Microsoft develops
  • SQL is a computer language used chiefly for database management and data retrieval. MySQL, on the other hand, is a SQL-based sound database system.
  • SQL supports multiple languages. However, MySQL is exclusively available in English.
  • MySQL does not support user-defined functions, unlike SQL. SQL is more flexible in this regard than MySQL.
  • SQL requires far less time to restore significant volumes of data than MySQL does for the same amount of data.

20. Identify And Describe The Various SQL Join Types

In SQL, there are four types of Join clauses:

  • Inner Join: It is the most prevalent Join type. It can choose and aggregate all rows from several tables. In the field that is shared, the value will be identical.
  • Right, Join: We utilize it to collect information from the right table and the corresponding rows or columns from the left table. It returns NULL if neither table contains any rows or columns that match.
  • Left Join: Is used to retrieve information from the left table and the corresponding rows or columns from the right table. It returns NULL if neither table contains any rows or columns that match.
  • Full Outer Join: Also known as a Full Outer Join. It is the combined output of Right Join and Left Join. The joined tables yield all records from both tables, and if there are no matches, they will insert NULL.

21. Describe The Many Approaches To The Normalization Process.

There are different distinct normalization form types. They include:

  • 1NF or First Normal Form: We use 1NF to overcome the atomicity problem. It assures that each column contains a unique value and that no cell contains multiple values.
  • 2NF or Second Normal Form: The initial prerequisite for 2NF is to meet all of the requirements in 1NF. Additionally, the table should prevent partial dependency. It is accomplished by separating subsets of data into different tables and establishing primary key-based associations between them.
  • 3NF, or Third Normal Form: 3NF is comparable to 2NF in that the first requirement is to meet the needs of 2NF. The following criteria are that the non-primary characteristics should not have transitive dependencies. In other words, non-prime attributes in a given table should not depend on other non-prime qualities.

22. What Is The Primary Distinction Between DELETE And TRUNCATE?

There are some distinctions between DELETE and TRUNCATE. They include the following:

  • The TRUNCATE command removes all rows in a table, while the DELETE command deletes individual rows.
  • The user can undo a DELETE operation but not a TRUNCATE operation.
  • The DELETE command is quicker than TRUNCATE.

23. What Are SQL Constraints?

Constraints are representations of a table’s data. Column-level constraints and table-level constraints are the two levels of Constraints in SQL. It can be implemented using the ALTER TABLE command during or after table creation. Among the SQL Constraints are the following:

  • The primary key identifies each record in a table.
  • Foreign Key: Preserves the referential integrity of another table’s record.
  • Unique: Ensures that unique values are entered into the field
  • This field facilitates faster data retrieval via the index.
  • If no value has been provided to the field, this property assures that a default value is assigned.
  • It verifies that the values in a field satisfy all of the specified conditions.
  • It prohibits NULL values from being entered into the column.

24. Describe All The Different Forms Of SQL Queries.

Describe the many forms of SQL queries.

  • The four distinct kinds of SQL queries are as follows:
  • Data Control Language, or DCL, is used to grant and revoke rights.
  • Transaction Control Language, or TCL, is used to save and restore database changes.
  • DDL stands for Data Definition Language and is utilized to build objects.
  • Data manipulation is performed using DML, or Data Manipulation Language.

25. Mention Several Advantages Of Adopting Amazon DynamoDB.

Amazon DynamoDB is a NoSQL service that offers numerous advantages to its consumers. Among the advantages of AWS DynamoDB are –

  • As a self-managed service, DynamoDB does not require the assistance of professionals for setup, installation, cluster, etc.
  • It offers inevitable and accelerated performance.
  • It is highly scalable, accessible, and long-lasting.
  • It offers an exceptionally high throughput and low latency.
  • It is pretty economical.
  • It supports and permits building dynamic tables with multi-value attributes, demonstrating its adaptability.

Conclusion

SQL is a typical component in Amazon interviews, regardless of position. From simple searches to sophisticated questions and sub-queries, it is best to be familiar with the syntax. This discussion section could determine whether a candidate is offered the position or asked to look elsewhere. Many people find the interview process to be lengthy and daunting. But it does not have to be that way! We provide the necessary sample responses to help you ace your interview with less anxiety and begin your ideal job.