This covers one of the most popular Spark interview questions of adding new columns to Spark Dataframes. Most non-trivial Spark jobs will have additional columns added to an existing Dataframe. These columns can be derived from existing columns in a Dataframe.
Q01. What are the different ways in which you can add new columns to a Dataframe?
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This extends Spark interview Q&As with coding examples in Scala – part 10: adding new columns. Q01. How will you add a new column with a fixed value? A01. Using the lit(..) & typedlit(..) functions in “org.apache.spark.sql.functions” … Read more ›...
Join operations are frequently used in big data analytics to merge two data sets, represented as tables, DataSets or DataFrames via on a matching key. Being aware of these join strategies is important as they can significantly impact the performance and efficiency of your Spark applications. Q1. … Read more...
This extends 15 Apache Spark best practices & performance tuning interview FAQs to delve into DAGs, Stages, Tasks, Partitions and Shuffling in Spark. If you can’t read Spark Event Timelines & DAGs, you will be running blind as to how efficient your code is. … Read more ›...
Q01 What is the difference between SQL stored Procedures & Functions?
A01 Stored procedure does not have a RETURNS clause, but you can use the OUT or INOUT parameter. Stored procedures are transactional whereas functions are not.
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Q1. What is a temporal table? A1. Temporal tables store and maintain information with respect to time. This tracks data changes, and enables us to maintain and manage the history of the data in a table. … Read more ›...
This question can reveal a lot about your ability to write SQL queries as different approaches can be used and there will be drill down on pros and cons of each approach. Q1. Given the following SQL, how do you retrieve the latest records by updated date for each user?...
Large mission critical applications use Straight Through Processing, and these systems need to be highly scalable. So, when you apply for these high paying jobs, it really pays to prepare for your job interviews with the following questions and answers.
Q. What is Straight Through Processing (STP)?
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In addition to the Data Analysts, the Data Engineers & Data Scientists must have the below know-hows.
Zookeeper solves challenges in a distributed system. This extends Apache Zookeeper interview Q&As and Getting started with Zookeeper tutorial. In this Zookeeper tutorial let’s use Docker. Zookeeper image in Docker Hub Step 1: Zookeeper image can be found at Docker Hub. … Read more ›...
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