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Home » 10 SQL Interview Coding Questions for Data Analysts and Data Scientists by SQL Fundamentals Aug, 2023

10 SQL Interview Coding Questions for Data Analysts and Data Scientists by SQL Fundamentals Aug, 2023

Data analysts use SQL to communicate with relational databases to access, clean, and analyze data. At the time of writing, more than 10,200 jobs in Canada on LinkedIn included SQL in the listing [1]. BAs play very important roles in organizations by helping them make better decisions. However, being a great business business analyst also requires technological skills, one of which is SQL.

sql interview questions and answers for data analyst

If there’s a more efficient way you could have written your code—using subqueries for example—explain that. Most commonly, candidates are provided a dataset and asked to write a SQL query to return the desired data. Data analyst SQL interviews aim to quickly evaluate your ability to extract metrics and work with data using SQL. You’ll usually need to write SQL queries on a whiteboard or in a code editor. Create a SQL query that only returns even rows from the table. This second category of questions gives you an SQL query and asks you a question about it.

What is a primary key?

A correlated subquery, on the other hand, uses values from the outer query and therefore depends on the outer query. Such a subquery executes repeatedly, once for each row that is selected by the outer query. A subquery is, as the name suggests, a query within another query. The outer query is called the main query, while the inner query is the subquery. A subquery is always executed first, and its result is then passed on to the main query. All the combined sheets or tables contain a common set of dimensions and measures.

Map out what are the smaller building blocks that are needed for the final solution. To see PostgreSQL date/time operators in action, let’s solve this TikTok SQL Assessment Question called 2nd-day confirmation which gives you a table of text message and email signup data. You’re asked to write a query to display the ids of the users who confirmed their phone number via text message on the day AFTER they signed up (aka their 2nd day on Tik-Tok). Similarly, if you wanted to count the total number of rows, you could use the aggregate function .

Data Analyst SQL Interview Question #2: How to Aggregate Distinct Data Values

To do that, you need to create a named range using the offset function and base the pivot table using a named range constructed in the first step. If you think a career as a data analyst could be a good fit, start building the skills you need for an entry-level role with a Professional Certificate on Coursera. A potential employer will want to see that you know the process and why it’s crucial. If you get asked the negative version of a question (least successful or most challenging project), be honest as you focus your answer on lessons learned.

sql interview questions and answers for data analyst

Hiring me would bring a dedicated data analyst who is poised to make a positive impact on your organization.” Data analytics is widely used in every sector in the 21st century. A career in the field of data analytics is highly lucrative in today’s times, with its career potential increasing by the day. Out of the many job roles in this field, a data analyst’s job role is widely popular globally.

Top Amazon/AWS Business Analyst Interview Questions (Updated

I recommend creating a study plan that allots oodles of time to practice the concepts too if you want to crack the SQL interview. Relational databases are the most common type of database, and they are used by most businesses because they are easy to use and easy to scale. A relational database is a database that stores data in tables. Tables are similar to folders in a file system, where each table stores data about a particular subject. For example, a customer orders table might store data about customer orders, and a product table might store data about products.

  • If the two are used together, the WHERE clause is applied first to filter rows; only after grouping finishes is the HAVING clause applied.
  • If you’re looking for more SQL interview prep, here are some free resources where you can practice writing queries.
  • For example the window function ranks selected rows in ascending order, but resets the ranks for each window.
  • Finally, we’ll ORDER BY a descending count of the sum of beds.
  • Subqueries are often used to find data that satisfies certain conditions; for example, you could use a subquery to find all customers who live in the same city as a particular customer.
  • The Except operator returns the uncommon records that are the results of 2 or more SELECT statements.
  • Suppose a company has created a search algorithm that will scan through user comments and display the search results to the user.

As a data analyst, you’ll likely have to use SQL and a statistical programming language like R or Python. Interested in becoming a data analyst but concerned about the data analyst interview questions and answers. Database design and data modeling interview questions test you on how well you understand the inner-workings of databases, along with how to design your data warehouse. If you’re preparing for a Data Engineering or Analytics Engineering interview, this section is just as important as being able to write SQL queries. A SQL aggregate function is a function that performs a calculation on a set of values and returns a single value. Aggregate functions are often used with the GROUP BY clause to return one result per group; for example, you could use the COUNT() function to find the number of customers in each city.

What are the various steps involved in any analytics project?

Inner joins return rows from both tables that have matching values in the specified columns, while outer joins return all rows from both tables, including rows with no matching values. Self-joins are used to join a table to itself; for example, you could use a self-join to find all customers who live in the same city as another customer. SQL is a powerful programming language that is widely used for managing and analyzing data.

sql interview questions and answers for data analyst

Often you might get a long SQL word problem, where you’ll have lots of extra details and it might not be clear what the interviewer is specifically asking you to query. So understanding and clarifying what specifically needs to be done is the best first step https://wizardsdev.com/en/vacancy/sql-and-data-analyst-bi-analyst/ to take. For example, SQL Server and MySQL have a function, but PostgreSQL uses the keyword to get the same results. While PostgreSQL technically has dozens of aggregate functions, 99% of the time you’ll just be using the big five functions covered below.

Q16. Mention the various user-defined functions.

The stored procedure is an SQL script that is used to run a task several times. Answer all of the given differences when this data analyst interview question is asked, and also give out the syntax for each to prove your thorough knowledge to the interviewer. Most entry-level data analyst roles will require at least a basic competency in statistics and an understanding of how statistical analysis ties into business goals. List the statistical calculations you’ve used and what business insights those calculations yielded. If you’re like many people, the job interview can be one of the most intimidating parts of the job search process. With some preparation, you can enter your data analyst interview feeling calm and confident.

sql interview questions and answers for data analyst

Because the SQL versions are pretty similar, most data job interviews don’t require you to use a specific version of SQL during the interview. This is a common SQL interview question that is designed to assess your real-world experience with the language. When answering this question, be sure to describe a specific problem that you were able to solve using SQL.

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