Blackbuck Insights Data Engineer Interview Questions and Answers

3 SQL and 2 Python questions were asked, SQL was moderate, Python was tough

It was a written test where theoretical SQL questions were asked like primary key, foreign key, set operators and some queries

Q1. All SQL Concepts like Join, normalization, trigger, stored procedure, keys, drop truncate del difference, where having difference, Aggregate scaler window functions, fetch duplicate records query, acid pro...read more
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Q1. Describe your workflow of the last project
Ans. 
Developed ETL pipeline to ingest, clean, and analyze customer data for personalized marketing campaigns
• Gathered requirements from stakeholders to understand data sources and business objectives

• Designed data model to store customer information and campaign performance metrics

• Implemented ETL process using Python and Apache Spark to extract, transform, and load data

• Performed data quality checks and created visualizations ...read more
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Q2. What are the different transformations you have used
Ans. 
I have used various transformations such as filtering, joining, aggregating, and pivoting in my data engineering projects.
• Filtering data based on certain conditions

• Joining multiple datasets together

• Aggregating data to summarize information

• Pivoting data from rows to columns or vice versa
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Q1. Ranking code in sql
Ans. 
Ranking code in SQL
• Use the RANK() function to assign a rank to each row based on a specified column

• Use the ORDER BY clause to determine the order of ranking

• Handle ties in ranking using the DENSE_RANK() function

• Use the ROW_NUMBER() function to assign a unique number to each row
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Q2. Read a file using python
Ans. 
To read a file using Python, use the open() function and specify the file path and mode.
• Use the open() function to open the file

• Specify the file path and mode (e.g., 'r' for reading)

• Read the contents of the file using the read() method

• Close the file using the close() method
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Q3. Reverse a array string using python
Ans. 
Reverses an array of strings using Python.
• Use the reverse() method to reverse the array in-place.

• Alternatively, use slicing with a step of -1 to create a new reversed array.

• Remember to convert the array to a list before reversing if necessary.
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