Hiring DEV Talent: SQL Interview Questions

With SQL taking its place among the most popular developing languages for the management of data, as per this 2021 report by Statista, SQL is pretty much the most popular language, and hiring developers for the same is a smart move to make.  This is why it is quite important for companies to take interest in it and to further make use of it

Organizations can use this language for data analysis, management, and much more. This is exactly why you want to make sure you find the right SQL coding developer for your organization.

Technical recruitment can be quite challenging but there are things you can do apart from just asking the same old questions for an effective interview process. Hiring developer needn’t be difficult at all, want to know how? Keep on reading

How Technical Recruiters Can Step Up Their Game

Given how the landscape of technical recruitment looks right now, especially post pandemic, it is imperative that recruiters level up their game.

Asking the same old SQL interview questions will not work as great as before, as a recruiter apart from looking for developers, you must also look for ways to render your recruitment game much more efficient. From learning new skills to being more inclusive in your approach, there are a ton of things you can do to keep pace with the ever-growing world of tech recruitment.

Set Clear Expectations

Setting clear expectations is something that should be among the top priorities in your recruitment process.

You can only assess the candidate thoroughly when the candidate understands what is expected of him/her. During the very first interview process, setting clear objectives is important. This also means that you will be offering your candidates a realistic preview of the job.

When you talk about objectives and expectations, you should get the candidate excited about the role. With clear objectives in mind, it will be easier for the candidate to understand what they must do to secure their position and they will also know what to expect from the job as well.

Use Real-World Problems

Hiring a skilled developer sounds good but know that just developing skills aren’t enough. Having adept problem-solving skills can go a long way, it can also improve their developing skills. Problem-solving is an indicator of a great employee.

To assess their problem-solving skills, you ought to use real-world problems. Using real-world scenarios will also give you a good idea about their skills, being able to solve real-world problems also showcases:

• Adaptability
• Creative thinking
• Analytical thinking

So by bringing this method to the table, you are not only hiring developers who know the language, but you are also hiring someone who will take initiative and try to bring out the best in themselves.

Look Beyond Technical Skills

As a follow-up to the point above, looking beyond technical skills and problem-solving skills definitely pays off.

It doesn’t matter how good the candidate is unless he is the right fit for the organization. You need to look for open-minded individuals who can be great team players as well. You need people who will stick around for a long period of time, someone who is befitting to the work environment the organization has to offer.

Use Tools

There are several platforms for hiring developers that take the process of screening and interviewing to a whole new level.

Gone are the days where you had to take an interview and then ask the candidate to write a code on paper. With interview and screening tools, you can request the candidate to work on a code right then and there, after which you can use assessment tools to give your candidate feedback immediately.

Also Read: 6 things to look for in your coding assessment tool

Online Tech Forums and Communities

Online Tech Forums and Communities is one of the best places to find developers. This concept is relatively new, but engaging with developers and coders through these forums will give you several options and also this is a way of sourcing candidates even before a job vacancy pops up.

SQL skills required for developers

SQL, or Structured Query Language, is the backbone of many modern data operations. But when hiring SQL developers, it’s essential to remember that you’re not just looking for someone who knows how to write a query. You’re searching for a multifaceted individual with a blend of technical knowledge and other attributes that make them an invaluable asset.

Here are the skills to look for:

Strong foundation in SQL: At its core, an SQL developer should possess a robust understanding of SQL syntax and structures. This includes crafting complex queries, understanding JOIN operations, and implementing sub-queries and triggers.

Database design and normalization: Proficiency in designing databases is crucial. A skilled developer should understand normalization principles to ensure data integrity and efficiency.

Knowledge of RDBMS: Familiarity with popular Relational Database Management Systems, like MySQL, PostgreSQL, Oracle, or SQL Server, is essential. Each system has its nuances, so knowledge of your specific platform is a plus.

Performance tuning: Writing an SQL query is one thing; optimizing it for performance is another. Candidates should know how to analyze query performance and make necessary adjustments.

Understanding of indexing: Knowing how and when to use indexes to optimize queries is a hallmark of an experienced SQL developer.

Stored procedures and functions: The ability to create and modify stored procedures and functions allows for more complex operations and can help with performance.

Integration skills: Often, SQL databases don’t stand alone. Your developer might need to integrate them with other systems, so familiarity with integration tools and methodologies is a plus.

Backup and recovery: An understanding of backup techniques, and secure methods, such as air gap backups,, as well as the ability to restore data in case of failures, is crucial.

ETL processes: For businesses that rely on data warehousing, knowledge of ETL (Extract, Transform, Load) processes can be invaluable.

Soft skills: Beyond the technical, effective communication is vital. SQL developers often need to collaborate with other teams, gather requirements, and sometimes explain complex data concepts in layman’s terms.

Problem-solving and analytical thinking: Databases often present intricate challenges. A sharp analytical mind, combined with a problem-solving attitude, can set a great SQL developer apart.

The tech world evolves rapidly. Along with these skills, a top SQL developer should also demonstrate a commitment to continuous learning, staying updated with the latest in database technologies and best practices. With increasing concerns about data breaches, an understanding of security protocols and best practices is also crucial.

Sample SQL Interview Questions

Here are a few sample questions you can refer to:

1. List out the standard SQL commands.
2. Explain the different subsets of SQL
3. Explain what Relational Database Management Is
4. List out the differences between outer join and inner join
5. How does data normalization work and what is its purpose?
6. What Is Union?
7. What is a UNIQUE constraint? Explain.
8. How do you copy one table to another?
9. How do you insert a row for identity column implicity?
10. Explain the difference between multiple-row functions and single-row functions
11. What would be the output of the below-mentioned query of an employee table with 10 records?

1. What is an execution plan? How do you view it and use it?
2. Given below is customer table with data for which you must write one SQL statement link and sequence customer names in the following single semicolon-separated string

Sebastian V; Akshay Varma; Manoj Kumar; Shrishti Singh; Abhay

1. Explain the difference between varchar2 and char?
2. What is the NVL function in SQL? How is it different from NVL2?
3. Give the SQL statement for the below
4. In the below mentioned table

Write a query to list out people who attended class more than once in a single day. Let the order start from the most recent and group it by the user and lesson attended.

These are some of the questions you can ask when you’re in the process of interviewing and a hiring developer, but remember that a well-planned recruitment strategy always pays off in a great manner.

Moreover, technology has the answer for all the above, there are multiple tools available through which you can elevate your recruitment strategy. Like HackerEarth’s live interview tool which allows real-time code editing, similarly, there are other tools.

So don’t wait too long to make your recruitment game strong.

Sonaksh Singh Author 12 Blogs