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Meesho PySpark Interview Questions for Data Engineers in 2025

Meesho PySpark Interview Questions for Data Engineers in 2025 Preparing for a PySpark interview? Let’s tackle some commonly asked questions, along with practical answers and insights to ace your next Data Engineering interview at Meesho or any top-tier tech company. 1. Explain how caching and persistence work in PySpark. When would you use cache() versus persist() and what are their performance implications? Answer : Caching : Stores data in memory (default) for faster retrieval. Use cache() when you need to reuse a DataFrame or RDD multiple times in a session without specifying storage levels. Example: python df.cache() df.count() # Triggers caching Persistence : Allows you to specify storage levels (e.g., memory, disk, or a combination). Use persist() when memory is limited, and you want a fallback to disk storage. Example: python from pyspark import StorageLevel df.persist(StorageLevel.MEMORY_AND_DISK) df.count() # Triggers persistence Performance Implications : cache() is ...

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UST Data Analyst Interview First-Round Questions

Cracking the UST Data Analyst Interview: First-Round Questions

If you’re gearing up for a data analyst interview at UST, you’ll need more than just technical know-how; clarity in explaining concepts is equally critical. Here’s how I tackled the first-round questions and prepared to ace the challenge!



📋 Top Questions and My Approach

1️⃣ Self-Introduction

Your introduction sets the tone for the interview. Here’s my strategy:

  • Start with a brief overview of your educational background.
  • Highlight your relevant experience, focusing on roles where you leveraged data analysis, SQL, or Power BI.
  • End with a mention of key projects, tools you’re proficient in, and what excites you about the role.

Example:
"Hi, I’m [Your Name], a data analyst with 3+ years of experience in leveraging SQL, Power BI, and Python to drive data-driven decisions. In my recent role, I designed dashboards to monitor KPIs, optimized queries for better performance, and collaborated with cross-functional teams to deliver actionable insights. I’m passionate about turning complex datasets into meaningful stories and am excited to bring this expertise to UST."


2️⃣ Which Data Sources Have You Used in Your Projects?

I’ve worked with a variety of data sources, including:

  • Relational Databases: SQL Server, MySQL, PostgreSQL
  • Cloud Data Warehouses: Snowflake, Google BigQuery
  • Files: Excel, CSV, JSON
  • APIs: REST APIs to fetch real-time data
  • Other Tools: SharePoint and flat files

Tip: Emphasize the versatility of your experience and provide examples.


3️⃣ What is DAX? Explain in Detail.

DAX (Data Analysis Expressions) is a formula language used in Power BI, Excel, and Analysis Services to perform calculations on data models.

Key points to include:

  • DAX is a functional language designed for creating measures, calculated columns, and custom tables.
  • It’s optimized for relational data models and works with columnar databases.
  • Common use cases: aggregations (SUM, AVG), time intelligence functions (YTD, MTD), and filtering.

Example Function:

DAX

SalesLastYear = CALCULATE(SUM(Sales[Amount]), SAMEPERIODLASTYEAR(Sales[Date]))

4️⃣ Difference Between a Dimension and a Measure in Power BI

  • Dimension: Represents qualitative data (e.g., categories, products, regions). Used to slice and filter data.
  • Measure: Represents quantitative, aggregated data (e.g., sum of sales, average profit). Calculated dynamically based on dimensions.

Analogy: Dimensions are like the “labels,” while measures are the “numbers” you analyze.


5️⃣ Types of DAX Functions You’ve Used

Some common DAX functions I’ve utilized:

  • Aggregate: SUM, AVERAGE, COUNT
  • Filter: CALCULATE, FILTER
  • Time Intelligence: YTD, QTD, SAMEPERIODLASTYEAR
  • Logical: IF, SWITCH

6️⃣ Difference Between MAX and MAXX Aggregate Functions

  • MAX: Returns the maximum value in a column.
    Example: MAX(Sales[Amount])
  • MAXX: Evaluates an expression for each row in a table and returns the maximum result.
    Example: MAXX(Sales, Sales[Quantity] * Sales[Price])

7️⃣ How Does the SUM Function Differ From SUMX in Power BI?

  • SUM: Performs a straightforward addition of all values in a column.
    Example: SUM(Sales[Amount])
  • SUMX: Iterates through a table, evaluating an expression for each row and then sums up the results.
    Example: SUMX(Sales, Sales[Quantity] * Sales[Price])

8️⃣ Finding Sales for Category A From a Table With Multiple Categories

DAX Solution:

DAX

SalesCategoryA = CALCULATE(SUM(Sales[Amount]), Sales[Category] = "A")

Alternatively, use a Power BI filter or slicer to display only Category A.


9️⃣ How Would a Matrix Visual Appear With Multiple Columns and Countries?

The matrix visual would display:

  • Rows: Hierarchies such as Product -> Subcategory.
  • Columns: Categories like Region -> Country.
  • Values: Aggregated metrics such as sales or revenue.

The visual creates a drill-down experience, allowing users to explore data interactively.


🔟 Write a SQL Query to Retrieve Specific Details

Example Question: Retrieve total sales and average sales per category for the last year.
Solution:

sql

SELECT
Category, SUM(SalesAmount) AS TotalSales, AVG(SalesAmount) AS AvgSales FROM Sales WHERE SaleDate >= DATEADD(YEAR, -1, GETDATE()) GROUP BY Category;

✨ Pro Tips for Preparation

  1. Practice Explaining: Be ready to explain your thought process for each question.
  2. Hands-On Practice: Use tools like Power BI and SQL databases to practice real-world scenarios.
  3. Mock Interviews: Simulate the interview environment to improve confidence.

📣 Let’s Learn Together!

These questions provide a strong foundation for UST’s Data Analyst role. If you’ve faced similar challenges or have tips, share them in the comments below!

Found this helpful? Give it a like and share it with your network to help others ace their interviews.

Hashtags:
#DataAnalyst #InterviewPreparation #

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