Data Analyst Cheatsheet 💪

Advanced Skills to Elevate Your Data Analytics Career

1️⃣ SQL Optimization & Performance Tuning

🚀 Learn indexing, query optimization, and execution plans to handle large datasets efficiently.

2️⃣ Machine Learning Basics

🤖 Understand supervised and unsupervised learning, feature engineering, and model evaluation to enhance analytical capabilities.

3️⃣ Big Data Technologies

🏗️ Explore Spark, Hadoop, and cloud platforms like AWS, Azure, or Google Cloud for large-scale data processing.

4️⃣ Data Engineering Skills

⚙️ Learn ETL pipelines, data warehousing, and workflow automation to streamline data processing.

5️⃣ Advanced Python for Analytics

🐍 Master libraries like Scikit-Learn, TensorFlow, and Statsmodels for predictive analytics and automation.

6️⃣ A/B Testing & Experimentation

🎯 Design and analyze controlled experiments to drive data-driven decision-making.

7️⃣ Dashboard Design & UX

🎨 Build interactive dashboards with Power BI, Tableau, or Looker that enhance user experience.

8️⃣ Cloud Data Analytics

☁️ Work with cloud databases like BigQuery, Snowflake, and Redshift for scalable analytics.

9️⃣ Domain Expertise

💼 Gain industry-specific knowledge (e.g., finance, healthcare, e-commerce) to provide more relevant insights.

🔟 Soft Skills & Leadership

💡 Develop stakeholder management, storytelling, and mentorship skills to advance in your career.

Hope it helps :)

#dataanalytics

Data Analyst Interview Questions & Preparation Tips

Be prepared with a mix of technical, analytical, and business-oriented interview questions.

1. Technical Questions (Data Analysis & Reporting)

SQL Questions:

How do you write a query to fetch the top 5 highest revenue-generating customers?

Explain the difference between INNER JOIN, LEFT JOIN, and FULL OUTER JOIN.

How would you optimize a slow-running query?

What are CTEs and when would you use them?

Data Visualization (Power BI / Tableau / Excel)

How would you create a dashboard to track key performance metrics?

Explain the difference between measures and calculated columns in Power BI.

How do you handle missing data in Tableau?

What are DAX functions, and can you give an example?

ETL & Data Processing (Alteryx, Power BI, Excel)

What is ETL, and how does it relate to BI?

Have you used Alteryx for data transformation? Explain a complex workflow you built.

How do you automate reporting using Power Query in Excel?


2. Business and Analytical Questions

How do you define KPIs for a business process?

Give an example of how you used data to drive a business decision.

How would you identify cost-saving opportunities in a reporting process?

Explain a time when your report uncovered a hidden business insight.


3. Scenario-Based & Behavioral Questions

Stakeholder Management:

How do you handle a situation where different business units have conflicting reporting requirements?

How do you explain complex data insights to non-technical stakeholders?

Problem-Solving & Debugging:

What would you do if your report is showing incorrect numbers?

How do you ensure the accuracy of a new KPI you introduced?

Project Management & Process Improvement:

Have you led a project to automate or improve a reporting process?

What steps do you take to ensure the timely delivery of reports?


4. Industry-Specific Questions (Credit Reporting & Financial Services)

What are some key credit risk metrics used in financial services?

How would you analyze trends in customer credit behavior?

How do you ensure compliance and data security in reporting?


5. General HR Questions

Why do you want to work at this company?

Tell me about a challenging project and how you handled it.

What are your strengths and weaknesses?

Where do you see yourself in five years?

How to Prepare?

Brush up on SQL, Power BI, and ETL tools (especially Alteryx).

Learn about key financial and credit reporting metrics.(varies company to company)

Practice explaining data-driven insights in a business-friendly manner.

Be ready to showcase problem-solving skills with real-world examples.

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Junior-level Data Analyst interview questions:

Introduction and Background

1. Can you tell me about your background and how you became interested in data analysis?
2. What do you know about our company/organization?
3. Why do you want to work as a data analyst?

Data Analysis and Interpretation

1. What is your experience with data analysis tools like Excel, SQL, or Tableau?
2. How would you approach analyzing a large dataset to identify trends and patterns?
3. Can you explain the concept of correlation versus causation?
4. How do you handle missing or incomplete data?
5. Can you walk me through a time when you had to interpret complex data results?

Technical Skills

1. Write a SQL query to extract data from a database.
2. How do you create a pivot table in Excel?
3. Can you explain the difference between a histogram and a box plot?
4. How do you perform data visualization using Tableau or Power BI?
5. Can you write a simple Python or R noscript to manipulate data?

Statistics and Math

1. What is the difference between mean, median, and mode?
2. Can you explain the concept of standard deviation and variance?
3. How do you calculate probability and confidence intervals?
4. Can you describe a time when you applied statistical concepts to a real-world problem?
5. How do you approach hypothesis testing?

Communication and Storytelling

1. Can you explain a complex data concept to a non-technical person?
2. How do you present data insights to stakeholders?
3. Can you walk me through a time when you had to communicate data results to a team?
4. How do you create effective data visualizations?
5. Can you tell a story using data?

Case Studies and Scenarios

1. You are given a dataset with customer purchase history. How would you analyze it to identify trends?
2. A company wants to increase sales. How would you use data to inform marketing strategies?
3. You notice a discrepancy in sales data. How would you investigate and resolve the issue?
4. Can you describe a time when you had to work with a stakeholder to understand their data needs?
5. How would you prioritize data projects with limited resources?

Behavioral Questions

1. Can you describe a time when you overcame a difficult data analysis challenge?
2. How do you handle tight deadlines and multiple projects?
3. Can you tell me about a project you worked on and your role in it?
4. How do you stay up-to-date with new data tools and technologies?
5. Can you describe a time when you received feedback on your data analysis work?

Final Questions

1. Do you have any questions about the company or role?
2. What do you think sets you apart from other candidates?
3. Can you summarize your experience and qualifications?
4. What are your long-term career goals?

Hope this helps you 😊

Quick Recap of SQL Concepts

1️⃣ FROM clause: Specifies the tables from which data will be retrieved.
2️⃣ WHERE clause: Filters rows based on specified conditions.
3️⃣ GROUP BY clause: Groups rows that have the same values into summary rows.
4️⃣ HAVING clause: Filters groups based on specified conditions.
5️⃣ SELECT clause: Specifies the columns to be retrieved.
6️⃣ WINDOW functions: Functions that perform calculations across a set of table rows.
7️⃣ AGGREGATE functions: Functions like COUNT, SUM, AVG that perform calculations on a set of values.
8️⃣ UNION / UNION ALL: Combines the result sets of multiple SELECT statements.
9️⃣ ORDER BY clause: Sorts the result set based on specified columns.
🔟 LIMIT / OFFSET (or FETCH / OFFSET in some databases): Controls the number of rows returned and starting point for retrieval.

𝐇𝐨𝐰 𝐭𝐨 𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐞 𝐘𝐨𝐮𝐫𝐬𝐞𝐥𝐟 𝐢𝐧 𝐚 𝐏𝐡𝐨𝐧𝐞 𝐈𝐧𝐭𝐞𝐫𝐯𝐢𝐞𝐰? [ Part-1]

𝐇𝐑: Hello, am I speaking with [Your Name]?

[Your Name]: Yes, this is [Your Name] speaking.

[Your Name]: May I know who is calling, please?

𝐇𝐑: Hi [Your Name], this is [HR's Name] from XYZ Company.

𝐇𝐑: I'm calling because you applied for the Data Analyst role at our company.

[Your Name]: Yes, that's correct. Thank you for reaching out.

𝐇𝐑: [Your Name], could you tell me a bit about yourself?

[Your Name]: Sure! I recently graduated with a bachelor's degree in [Your Degree] from [Your University]. During my studies, I developed a strong interest in data analytics, particularly in how data can drive decision-making and improve business outcomes.

In college, I took courses in statistics, data visualization, and programming, which gave me a solid foundation in data analytics concepts. I also completed an internship at [Internship Company], where I worked on [specific project or task], honing my skills in data analysis and gaining hands-on experience with tools like Excel, SQL, and Python.

Now, I'm eager to apply my knowledge and skills in a professional setting and contribute to XYZ Company's success. I'm particularly drawn to your company's innovative approach to [specific area related to the company's work] and believe that my background and enthusiasm for data analytics would make me a valuable addition to your team.

𝐇𝐑: That sounds great, [Your Name]! Thank you for sharing.

[Your Name]: Thank you for giving me the opportunity!

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Complete Power BI Topics for Data Analysts 👇👇

1. Introduction to Power BI
- Overview and architecture
- Installation and setup

2. Loading and Transforming Data
- Connecting to various data sources
- Data loading techniques
- Data cleaning and transformation using Power Query

3. Data Modeling
- Creating relationships between tables
- DAX (Data Analysis Expressions) basics
- Calculated columns and measures

4. Data Visualization
- Building reports and dashboards
- Visualization best practices
- Custom visuals and formatting options

5. Advanced DAX
- Time intelligence functions
- Advanced DAX functions and scenarios
- Row context vs. filter context

6. Power BI Service
- Publishing and sharing reports
- Power BI workspaces and apps
- Power BI mobile app

7. Power BI Integration
- Integrating Power BI with other Microsoft tools (Excel, SharePoint, Teams)
- Embedding Power BI reports in websites and applications

8. Power BI Security
- Row-level security
- Data source permissions
- Power BI service security features

9. Power BI Governance
- Monitoring and managing usage
- Best practices for deployment
- Version control and deployment pipelines

10. Advanced Visualizations
- Drillthrough and bookmarks
- Hierarchies and custom visuals
- Geo-spatial visualizations

11. Power BI Tips and Tricks
- Productivity shortcuts
- Data exploration techniques
- Troubleshooting common issues

12. Power BI and AI Integration
- AI-powered features in Power BI
- Azure Machine Learning integration
- Advanced analytics in Power BI

13. Power BI Report Server
- On-premises deployment
- Managing and securing on-premises reports
- Power BI Report Server vs. Power BI Service

14. Real-world Use Cases
- Case studies and examples
- Industry-specific applications
- Practical scenarios and solutions

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Most Asked SQL Interview Questions at MAANG Companies🔥🔥

Preparing for an SQL Interview at MAANG Companies? Here are some crucial SQL Questions you should be ready to tackle:

1. How do you retrieve all columns from a table?

SELECT * FROM table_name;

2. What SQL statement is used to filter records?

SELECT * FROM table_name
WHERE condition;

The WHERE clause is used to filter records based on a specified condition.

3. How can you join multiple tables? Describe different types of JOINs.

SELECT columns
FROM table1
JOIN table2 ON table1.column = table2.column
JOIN table3 ON table2.column = table3.column;

Types of JOINs:

1. INNER JOIN: Returns records with matching values in both tables

SELECT * FROM table1
INNER JOIN table2 ON table1.column = table2.column;

2. LEFT JOIN: Returns all records from the left table & matched records from the right table. Unmatched records will have NULL values.

SELECT * FROM table1
LEFT JOIN table2 ON table1.column = table2.column;

3. RIGHT JOIN: Returns all records from the right table & matched records from the left table. Unmatched records will have NULL values.

SELECT * FROM table1
RIGHT JOIN table2 ON table1.column = table2.column;

4. FULL JOIN: Returns records when there is a match in either left or right table. Unmatched records will have NULL values.

SELECT * FROM table1
FULL JOIN table2 ON table1.column = table2.column;

4. What is the difference between WHERE & HAVING clauses?

WHERE: Filters records before any groupings are made.

SELECT * FROM table_name
WHERE condition;

HAVING: Filters records after groupings are made.

SELECT column, COUNT(*)
FROM table_name
GROUP BY column
HAVING COUNT(*) > value;

5. How do you calculate average, sum, minimum & maximum values in a column?

Average: SELECT AVG(column_name) FROM table_name;

Sum: SELECT SUM(column_name) FROM table_name;

Minimum: SELECT MIN(column_name) FROM table_name;

Maximum: SELECT MAX(column_name) FROM table_name;

Here you can find essential SQL Interview Resources👇
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1. List the different types of relationships in SQL.

One-to-One - This can be defined as the relationship between two tables where each record in one table is associated with the maximum of one record in the other table.
One-to-Many & Many-to-One - This is the most commonly used relationship where a record in a table is associated with multiple records in the other table.
Many-to-Many - This is used in cases when multiple instances on both sides are needed for defining a relationship.
Self-Referencing Relationships - This is used when a table needs to define a relationship with itself.

2. What are the different views available in Power BI Desktop?

There are three different views in Power BI, each of which serves another purpose:
Report View - In this view, users can add visualizations and additional report pages and publish the same on the portal.
Data View - In this view, data shaping can be performed using Query Editor tools.
Model View - In this view, users can manage relationships between complex datasets.


3. What are macros in Excel?

Excel allows you to automate the tasks you do regularly by recording them into macros. So, a macro is an action or a set of them that you can perform n number of times. For example, if you have to record the sales of each item at the end of the day, you can create a macro that will automatically calculate the sales, profits, loss, etc and use the same for the future instead of manually calculating it every day.

Here's Part 3 of the phone interview series for data analysts:

𝐃𝐞𝐬𝐜𝐫𝐢𝐛𝐞 𝐲𝐨𝐮𝐫 𝐩𝐫𝐨𝐜𝐞𝐬𝐬 𝐟𝐨𝐫 𝐬𝐨𝐥𝐯𝐢𝐧𝐠 𝐚 𝐝𝐚𝐭𝐚 𝐚𝐧𝐚𝐥𝐲𝐬𝐢𝐬 𝐩𝐫𝐨𝐛𝐥𝐞𝐦.

𝐇𝐑: [Your Name], can you describe your process for solving a data analysis problem?

[Your Name]: Certainly! When approaching a data analysis problem, I typically follow a structured process that involves several key steps:

1. Understanding the Problem: The first step is to clearly understand the problem at hand. I make sure to define the objectives and identify the key questions that need to be answered. This often involves communicating with stakeholders to ensure we're aligned on the goals.

2. Data Collection: Once the problem is defined, I gather the necessary data. This could involve extracting data from databases, collecting data from various sources, or working with existing datasets. Ensuring data quality is crucial at this stage.

3. Data Cleaning: Data often comes with inconsistencies, missing values, or errors. I spend time cleaning the data to ensure it's accurate and reliable. This step involves handling missing data, removing duplicates, and correcting errors.

4. Exploratory Data Analysis (EDA): After cleaning the data, I perform exploratory data analysis to uncover initial insights and patterns. This involves visualizing the data, calculating summary statistics, and identifying any outliers or trends.

5. Data Modeling: Depending on the problem, I might apply statistical models or machine learning algorithms to analyze the data. This step involves selecting the appropriate model, training it on the data, and evaluating its performance.

6. Interpretation and Presentation: Once the analysis is complete, I interpret the results and draw meaningful conclusions. I create visualizations and reports to present the findings in a clear and concise manner, making sure to tailor the presentation to the audience.

7. Recommendations and Actionable Insights: Finally, I provide recommendations based on the analysis. The goal is to offer actionable insights that can help the stakeholders make informed decisions.

𝐇𝐑: That's a comprehensive process. Can you give me an example of a project where you applied this process?

[Your Name]: Sure! During my internship at [Internship Company], I worked on a project to analyze customer purchase behavior. We aimed to identify patterns and trends to help the marketing team develop targeted campaigns.

𝐇𝐑: Can you walk me through how you applied each step to that project?

[Your Name]: Absolutely. First, I met with the marketing team to understand their objectives and the specific questions they had. We defined our goals as identifying key customer segments and their purchasing habits.

Next, I collected data from the company's CRM and sales databases. The data was then cleaned to remove duplicates and correct any inconsistencies.

During the exploratory data analysis, I used visualizations to identify initial trends and patterns. For example, I discovered that certain customer segments had distinct purchasing patterns during different seasons.

I then applied clustering algorithms to segment the customers based on their behavior. This helped us identify distinct groups with unique characteristics.

The results were presented to the marketing team using dashboards and visualizations created in Tableau. I highlighted the key findings and provided actionable recommendations for targeted marketing campaigns.

𝐇𝐑: That's an excellent example. It sounds like you have a solid approach to tackling data analysis problems.

[Your Name]: Thank you! I believe a structured process is essential to ensure thorough and accurate analysis.

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Netflix Analytics Engineer Interview Question (SQL) 🚀
---

### Scenario Overview
Netflix wants to analyze user engagement with their platform. Imagine you have a table called netflix_data with the following columns:
- user_id: Unique identifier for each user
- subnoscription_plan: Type of subnoscription (e.g., Basic, Standard, Premium)
- genre: Genre of the content the user watched (e.g., Drama, Comedy, Action)
- timestamp: Date and time when the user watched a show
- watch_duration: Length of time (in minutes) a user spent watching
- country: User’s country

The main objective is to figure out how to get insights into user behavior, such as which genres are most popular or how watch duration varies across subnoscription plans.

---

### Typical Interview Question

> “Using the netflix_data table, find the top 3 genres by average watch duration in each subnoscription plan, and return both the genre and the average watch duration.”

This question tests your ability to:
1. Filter or group data by subnoscription plan.
2. Calculate average watch duration within each group.
3. Sort results to find the “top 3” within each group.
4. Handle tie situations or edge cases (e.g., if there are fewer than 3 genres).

---

### Step-by-Step Approach

1. Group and Aggregate
Use the GROUP BY clause to group by subnoscription_plan and genre. Then, use an aggregate function like AVG(watch_duration) to get the average watch time for each combination.

2. Rank Genres
You can utilize a window function—commonly ROW_NUMBER() or RANK()—to assign a ranking to each genre within its subnoscription plan, based on the average watch duration. For example:

   AVG(watch_duration) OVER (PARTITION BY subnoscription_plan ORDER BY AVG(watch_duration) DESC)
   

(Note that in many SQL dialects, you’ll need a subquery because you can’t directly apply an aggregate in the ORDER BY of a window function.)

3. Select Top 3
After ranking rows in each partition (i.e., subnoscription plan), pick only the top 3 by watch duration. This could look like:

   SELECT subnoscription_plan,
          genre,
          avg_watch_duration
   FROM (
       SELECT subnoscription_plan,
              genre,
              AVG(watch_duration) AS avg_watch_duration,
              ROW_NUMBER() OVER (
                  PARTITION BY subnoscription_plan 
                  ORDER BY AVG(watch_duration) DESC
              ) AS rn
       FROM netflix_data
       GROUP BY subnoscription_plan, genre
   ) ranked
   WHERE rn <= 3;
   

4. Validate Results
- Make sure each subnoscription plan returns up to 3 genres.
- Check for potential ties. Depending on the question, you might use RANK() or DENSE_RANK() to handle ties differently.
- Confirm the data type and units for watch_duration (minutes, seconds, etc.).

---

### Key Takeaways
- Window Functions: Essential for ranking or partitioning data.
- Aggregations & Grouping: A foundational concept for Analytics Engineers.
- Data Validation: Always confirm you’re interpreting columns (like watch_duration) correctly.

By mastering these techniques, you’ll be better prepared for SQL interview questions that delve into real-world scenarios—especially at a data-driven company like Netflix.

Quick Power BI Dax Revision

1. Measures: Measures in DAX are calculations that are used in Power BI to perform aggregations, calculations, and comparisons on data. They are defined using the DEFINE MEASURE or CALCULATE functions.

2. Calculated Columns: Calculated columns are columns that are created in a table by using DAX expressions. They are calculated row by row when the data is loaded into the model.

3. DAX Functions: DAX provides a wide range of functions for data manipulation and calculation. Some common functions include SUM, AVERAGE, COUNT, FILTER, CALCULATE, RELATED, ALL, ALLEXCEPT, and many more.

4. Context: DAX calculations are performed within a context, which can be row context or filter context. Understanding how context works is crucial for writing accurate DAX expressions.

5. Relationships: Power BI data models are built on relationships between tables. DAX expressions can leverage these relationships to perform calculations across related tables.

6. Time Intelligence Functions: DAX includes a set of time intelligence functions that enable you to perform calculations based on dates and time periods. Examples include TOTALYTD, SAMEPERIODLASTYEAR, DATESBETWEEN, etc.

7. Variables: DAX allows you to declare and use variables within expressions to improve readability and performance of complex calculations.

8. Aggregation Functions: DAX provides aggregation functions like SUMX, AVERAGEX, COUNTX that allow you to iterate over a table and perform aggregations based on specified conditions.

9. Logical Functions: DAX includes logical functions such as IF, AND, OR, SWITCH that help in implementing conditional logic within calculations.

10. Error Handling: DAX provides functions like ISBLANK, IFERROR, BLANK, etc., for handling errors and missing data in calculations.

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Power BI Resources: https://whatsapp.com/channel/0029Vai1xKf1dAvuk6s1v22c

Complete SQL Topics for Data Analysts 😄👇

1. Introduction to SQL:
- Basic syntax and structure
- Understanding databases and tables

2. Querying Data:
- SELECT statement
- Filtering data using WHERE clause
- Sorting data with ORDER BY

3. Joins:
- INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN
- Combining data from multiple tables

4. Aggregation Functions:
- GROUP BY
- Aggregate functions like COUNT, SUM, AVG, MAX, MIN

5. Subqueries:
- Using subqueries in SELECT, WHERE, and HAVING clauses

6. Data Modification:
- INSERT, UPDATE, DELETE statements
- Transactions and Rollback

7. Data Types and Constraints:
- Understanding various data types (e.g., INT, VARCHAR)
- Using constraints (e.g., PRIMARY KEY, FOREIGN KEY)

8. Indexes:
- Creating and managing indexes for performance optimization

9. Views:
- Creating and using views for simplified querying

10. Stored Procedures and Functions:
- Writing and executing stored procedures
- Creating and using functions

11. Normalization:
- Understanding database normalization concepts

12. Data Import and Export:
- Importing and exporting data using SQL

13. Window Functions:
- ROW_NUMBER(), RANK(), DENSE_RANK(), and others

14. Advanced Filtering:
- Using CASE statements for conditional logic

15. Advanced Join Techniques:
- Self-joins and other advanced join scenarios

16. Analytical Functions:
- LAG(), LEAD(), OVER() for advanced analytics

17. Working with Dates and Times:
- Date and time functions and formatting

18. Performance Tuning:
- Query optimization strategies

19. Security:
- Understanding SQL injection and best practices for security

20. Handling NULL Values:
- Dealing with NULL values in queries

Ensure hands-on practice on these topics to strengthen your SQL skills.

Since SQL is one of the most essential skill for data analysts, I have decided to teach each topic daily in this channel for free. Like this post if you want me to continue this SQL series 👍♥️

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