Technical interview questions

This section will address technical interview questions specifically focused on SQL for data engineers. These questions will help you demonstrate your SQL proficiency and problem-solving abilities. Let’s explore a combination of primary and advanced SQL interview questions and the best methods to approach and answer them, as follows:

• Question 1: What is the difference between the WHERE and HAVING clauses?

  Answer: The WHERE clause filters data based on conditions applied to individual rows, while the HAVING clause filters data based on grouped results. Use WHERE for filtering before aggregating data and HAVING for filtering after aggregating data.

• Question 2: How do you eliminate duplicate records from a result set?

  Answer: Use the DISTINCT keyword in the SELECT statement to eliminate duplicate records and retrieve unique values from a column or combination of columns.

• Question 3: What are primary keys and foreign keys in SQL?

  Answer...