Celebal Technologies Associate Data Engineer Interview Questions and Answers

Q1. What is the SQL query used to remove duplicates from a dataset?
Ans. 
Use the DISTINCT keyword in a SELECT query to remove duplicates from a dataset.
• Use the SELECT DISTINCT statement to retrieve unique rows from a table

• Example: SELECT DISTINCT column1, column2 FROM table_name;

• Another way is to use the GROUP BY clause with aggregate functions like COUNT() or SUM() to remove duplicates
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Q2. What is the SQL query to find the third highest salary in a table?
Ans. 
Use a subquery to find the third highest salary in a table using SQL.
• Use the ORDER BY clause to sort the salaries in descending order.

• Use the LIMIT clause to limit the results to the third row.

• Use a subquery to select the third highest salary from the sorted list.
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Q1. What are the different roles in Power BI?
Ans. 
Different roles in Power BI include Power BI Developer, Power BI Analyst, Power BI Administrator, and Power BI User.
• Power BI Developer - responsible for creating and maintaining Power BI reports and dashboards

• Power BI Analyst - analyzes data using Power BI to provide insights and recommendations

• Power BI Administrator - manages security, access, and data sources in Power BI

• Power BI User - consumes reports and dashboards
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Q2. SQL - basicand advanced questions
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It was well designed

Q1. Basic Questions about data warehousing
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Q2. Dbt Scenarios
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Q1. Basicn details to check for qualifications
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Q1. About my projects
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Q1. More details about ML models
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Q1. Cache vs persist
Ans. 
Cache is used for temporary storage of data in memory, while persist is used for saving data to disk for long-term storage.
• Cache is typically faster as it stores data in memory for quick access.

• Persist saves data to disk for durability and long-term storage.

• Cache is often used for temporary data that can be recomputed if lost, while persist is used for important data that needs to be retained.

• Examples: Using cache for ...read more
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Q2. Broadcast join and other optimization techniques
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Q1. Sql window function
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Q2. Spark architecture, dataframe vs rdd
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Q3. Python reverse sentence
Ans. 
Reverse a sentence using Python
• Split the sentence into words using split() method

• Reverse the list of words using list slicing

• Join the reversed list of words back into a sentence using join() method
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Q4. Join based on nulls in sql
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Q1. Tell me about your self?
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Q2. What technology & tools u know ? And basic questions regarding that topics ?
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Q1. Job culture and job responsibilities ?
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Q2. Some questions on an analytical tools like power BI ?
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It contain both Aptitude and Coding about base models and Deep learning too

Q1. What different models technique ?
Ans. 
Different models techniques include linear regression, decision trees, random forests, support vector machines, and neural networks.
• Linear regression is used for predicting continuous values.

• Decision trees are used for classification and regression tasks.

• Random forests are an ensemble method based on decision trees.

• Support vector machines are used for classification tasks.

• Neural networks are used for complex pattern re
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Q2. What are performance metric where to use what?
Ans. 
Different performance metrics are used for different types of machine learning models to evaluate their effectiveness.
• For classification models, metrics like accuracy, precision, recall, F1 score, and ROC-AUC are commonly used.

• For regression models, metrics like mean squared error (MSE), mean absolute error (MAE), and R-squared are commonly used.

• For clustering models, metrics like silhouette score and Davies-Bouldin in...read more
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Q1. Explain about Project
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Q2. What are problems faced in that project?
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Highly interactive and technical

1 hr test with focus on math and analytical thinking