AXIS MY INDIA Data Analyst Interview Questions and Answers

Coalesce is a function used to return the first non-null value in a list of expressions.

• Coalesce function is commonly used in SQL to handle null values.

• It takes multiple arguments and returns the first non-null value.

• Example: COALESCE(column1, column2, 'default') will return the value of column1 if not null, else column2, and if both are null, it will return 'default'.

Repartition is the process of redistributing data across partitions in a distributed system.

• Repartitioning helps in balancing the workload and improving performance in distributed computing environments.

• It involves moving data between partitions based on certain criteria such as key values or hash functions.

• Repartitioning can be done in Spark using operations like repartition() or coalesce().

A non repeatable character is a character that appears only once in a given string.

• Iterate through the string and count the frequency of each character

• Identify the characters that have a frequency of 1

• Return the first non repeatable character found

Sort list without using sort method

• Create a custom sorting function using loops

• Compare each element with every other element to determine the correct order

• Swap elements based on the comparison results

Blend combines data from different data sources in a single view, while join combines data from the same data source.

• Blend is used when data comes from different data sources, join is used when data comes from the same data source

• Blend creates a relationship between data sources without actually merging the data, join merges the data based on a common field

• Blend can be used to combine data from different databases like...read more

Tableau architecture is a visual analytics platform that helps users to understand data through interactive visualizations.

• Tableau consists of three main components: Data Connection, Data Engine, and VizQL Server.

• Data Connection allows users to connect to various data sources such as databases, spreadsheets, and cloud services.

• Data Engine processes and optimizes data queries for faster performance.

• VizQL Server translat...read more

The top 10 and bottom 10 employees based on their rank need to be identified.

• Sort the employees based on their rank in ascending order.

• Select the top 10 employees from the sorted list.

• Select the bottom 10 employees from the sorted list.

Blend combines data from different data sources in a single view, while join combines data from the same data source.

• Blend is used when data comes from different data sources, join is used when data comes from the same data source

• Blend creates a relationship between data sources without actually merging the data, join merges the data based on a common field

• Blend can be used to combine data from different databases like...read more