Data Analyst Interview Cheat Sheet: Confidently Answer SQL, Python & Power BI Questions in 2025

Preparing for a Data Analyst interview? It’s not just about memorizing answers—it’s about understanding how pros think, analyze, and communicate data insights clearly. This cheat sheet combines key topics in SQL, Python, and Power BI to help you sound structured, confident, and job-ready.

Key SQL Interview Questions & Tips

Joins: Understand INNER, LEFT, RIGHT, and FULL JOIN. Be ready to explain and write queries using these.
Aggregations: Practice GROUP BY, HAVING, and aggregate functions like COUNT, SUM, AVG.
Data Handling: Know how to handle NULLs, find duplicates, and optimize slow queries.
Window Functions: Learn ROW_NUMBER, RANK, DENSE_RANK usage with OVER clause.
Sample Query: Get top 5 products by sales, find second-highest salary, or find missing data records.

Example:

𝐏𝐚𝐲 𝐀𝐟𝐭𝐞𝐫 𝐏𝐥𝐚𝐜𝐞𝐦𝐞𝐧𝐭 𝐓𝐫𝐚𝐢𝐧𝐢𝐧𝐠 𝐏𝐫𝐨𝐠𝐫𝐚𝐦- 𝐆𝐞𝐭 𝐏𝐥𝐚𝐜𝐞𝐝 𝐈𝐧 𝐓𝐨𝐩 𝐌𝐍𝐂'𝐬

sqlSELECT product_id, SUM(sales) AS total_sales  
FROM Sales  
GROUP BY product_id  
ORDER BY total_sales DESC  
LIMIT 5;

Must-Know Python Questions & Practices

Data Structures: Differentiate list, set, tuple, and dictionary.
Pandas: Master DataFrame operations like filtering, grouping, merging, handling missing data.
Data Cleaning: Write functions to remove duplicates, fill missing values, and rename columns.
Analysis: Use groupby() for aggregation, apply() and map() for transformations.
Sample Code: Calculate mean, median, mode of a dataset.

Example:

pythonimport pandas as pd  

df = pd.read_csv('data.csv')  
print(df['column'].mean())

Power BI Interview Focus Areas

Desktop vs Service: Know the difference between Power BI Desktop and Power BI Service.
DAX Functions: Be familiar with CALCULATE, FILTER, RELATED, and how to write Measures vs Calculated Columns.
Data Modeling: Handle relationships, hierarchies, and different types of joins in Power Query.
Security & Sharing: Explain Row-Level Security (RLS) and how to share dashboards securely.
Performance: Suggest ways to optimize reports and refresh data faster.

Soft Tips for Interview Success

Clearly explain your thought process when answering.
Use structured frameworks (e.g., STAR) to showcase problem-solving.
When stuck, ask clarifying questions or explain how you’d approach finding a solution.
Prepare to discuss past projects or practical experience using these tools.

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