PySpark interview question [2026]
Vishal Jadhav Top 50 recently asked Pyspark Interview Questions Big Data
Vishal Jadhav
Surrogate key
Surrogate keys are artificially generated primary keys, typically integers, used to uniquely identify records. In data warehouse you may have same record with multiple entries(this records columns value may change…
SQL Aggregate Functions – COUNT, MIN, MAX, AVG, SUM with Examples
SQL also supports the use of aggregate expressions (or functions) that allow you to summarize information about a group of rows of data. SELECT AGG_FUNC(column_or_expression) AS aggregate_description, … FROM mytable…
SQL Joins Explained: Inner, Left, Right, Full, Anti, Self & Natural Joins
A JOIN clause is used to query and access data from multiple tables by using logical relationships between them. Join syntax SELECT column, another_column, … FROM mytable INNER/LEFT/RIGHT/FULL JOIN another_table…
How to delete duplicates from a table
To delete duplicates from a table, you’ll need to identify the duplicate rows first and then delete them using SQL. The approach varies slightly depending on whether you’re working with…
How to find duplicates in a table
Identify duplicates criteria The first step is to define your criteria for a duplicate row. Do you need a combination of two columns to be unique together, or are you…
SQL LIMIT & OFFSET – SELECT ROW
SQL LIMIT and OFFSET LIMIT: Limits the number of rows returned by a query OFFSET: Specifies how many rows to skip before returning the results Here’s an example of using…
Pyspark Zero to Expert Tutorial
Pyspak complete tutorial from scratch Shuffle: when data persists and is shared with other executors.whenever shuffle happens job is get divided into stages Driver Executor in the following diagram, the…
partition and clustering – BigQuery
Table of Contents Toggle Limitations can you create a partition without clustering? Limitations maximum 8000 partitions possible on a single table and upto 4 columns can be used for clustering…
Time travel – BigQuery
Table of Contents Toggle what is time travel in bigquery? Big query time travel – query for extracting data for last 24 hour. what is time travel in bigquery? Using…