PivotRoots Data Analyst Interview Questions and Answers

Q1. Difference between union and union all in SQL?
Ans. 
Union combines and removes duplicates, Union All combines without removing duplicates.
• Union combines result sets and removes duplicates

• Union All combines result sets without removing duplicates

• Union is slower than Union All as it involves removing duplicates

• Example: SELECT column1 FROM table1 UNION SELECT column1 FROM table2;

• Example: SELECT column1 FROM table1 UNION ALL SELECT column1 FROM table2;
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Q2. How to show top 5 in pandas?
Ans. 
To show top 5 in pandas, use the nlargest() function.
• Use the nlargest() function with the 'n' parameter set to 5 to get the top 5 values in a pandas DataFrame.

• For example: df['column_name'].nlargest(5) will return the top 5 values in the specified column.
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Q1. If we have 3 numerical columns, which chart is a better representation these column?
Ans. 
A scatter plot is a better representation for 3 numerical columns.
• Use a scatter plot to show the relationship between the numerical columns.

• Scatter plots are effective for visualizing correlations and patterns in data.

• Each point on the plot represents a data point with values from all 3 columns.
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Q1. SQL Window Functions and RANK, DENSE RANK Difference
Ans. 
SQL Window Functions like RANK and DENSE RANK are used to assign a rank to rows within a partition.
• RANK function assigns a unique rank to each distinct row within a partition.

• DENSE RANK function assigns a unique rank to each distinct row within a partition, but without any gaps.

• Both functions are used with the OVER() clause in SQL to define the partition and order of rows.
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Q2. Hadoop Default Replication Factor
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Q1. Questions on vlook up, h-look up, pivot and if else condition
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Q2. You must know how to use vlook up, h-look up and if-else condition
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Excel file was give, used sumifs, countifs , index match formulas

Q1. Difference between union and union all in SQL?
Ans. 
Union combines and removes duplicates, Union All combines without removing duplicates.
• Union combines result sets and removes duplicates

• Union All combines result sets without removing duplicates

• Union is slower than Union All as it involves removing duplicates

• Example: SELECT column1 FROM table1 UNION SELECT column1 FROM table2;

• Example: SELECT column1 FROM table1 UNION ALL SELECT column1 FROM table2;
Answered by AI
Add your answer
Q2. How to show top 5 in pandas?
Ans. 
To show top 5 in pandas, use the nlargest() function.
• Use the nlargest() function with the 'n' parameter set to 5 to get the top 5 values in a pandas DataFrame.

• For example: df['column_name'].nlargest(5) will return the top 5 values in the specified column.
Answered by AI
Add your answer

Q1. If we have 3 numerical columns, which chart is a better representation these column?
Ans. 
A scatter plot is a better representation for 3 numerical columns.
• Use a scatter plot to show the relationship between the numerical columns.

• Scatter plots are effective for visualizing correlations and patterns in data.

• Each point on the plot represents a data point with values from all 3 columns.
Answered by AI
Add your answer

Basic dsa question in python and data engineering questions ,sql

Basic dsa question in python and data engineering questions

Q1. Salary negotiation
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Q1. Majorly about previous work experience.
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Q1. Asked me to build a dashboard in Google sheet and advance Excel test
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Q1. Salary and other discussions
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