Tableau Interview Questions with Answers Part-5 ✅📊

41. What are the different file types in Tableau (.twb,.twbx,.tds)?
⦁ .twb — Tableau Workbook (XML containing viz instructions, no data)
⦁ .twbx — Packaged Workbook (twb + data + images compressed)
⦁ .tds — Tableau Data Source (metadata about connections and calculations, no data)

42. How do you embed a Tableau dashboard into a web page?
You can generate an embed code (iframe) from Tableau Server/Online or Tableau Public and insert it into your web page’s HTML for seamless embedding.

43. What is the difference between Tableau Public and Tableau Desktop?
Tableau Desktop is the full-featured paid software for building dashboards privately; Tableau Public is a free version where workbooks and data are stored publicly.

44. What are extensions in Tableau?
Extensions are add-ons that enhance Tableau dashboards with custom features, such as input forms or integration with other applications, available via Tableau Extension Gallery.

45. How do you handle large datasets in Tableau?
Use extracts, aggregates, filters, context filters, minimize marks, optimize data sources, and leverage Tableau’s Hyper engine for better performance.

46. Explain the use of context filters.
Context filters create a temporary subset of data that other filters depend on, improving performance with large data sets and enabling dependent filtering.

47. What are data source filters?
Filters applied at the data source level to restrict the data available for all users and workbooks using that source.

48. What are the latest features of Tableau?
Features like improved AI-powered Ask Data, dynamic parameters, accelerated data prep with Tableau Prep improvements, and better data governance and collaboration tools (2025 updates).

49. How do you use Tableau with cloud data sources?
Connect directly to cloud databases (AWS Redshift, Snowflake, Google BigQuery, Azure SQL), use live connections or extracts, and leverage Tableau’s native cloud integrations.

50. How do you troubleshoot common Tableau errors?
Check data source connectivity, review calculated fields for syntax errors, verify filters and actions, optimize performance, and consult Tableau logs for detailed error info.

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Top 10 SQL interview questions with solutions by @sqlspecialist

1. What is the difference between WHERE and HAVING?

Solution:

WHERE filters rows before aggregation.

HAVING filters rows after aggregation.

SELECT department, AVG(salary)
FROM employees
WHERE salary > 3000
GROUP BY department
HAVING AVG(salary) > 5000;

2. Write a query to find the second-highest salary.

Solution:

SELECT MAX(salary) AS second_highest_salary
FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);

3. How do you fetch the first 5 rows of a table?

Solution:

SELECT * FROM employees
LIMIT 5; -- (MySQL/PostgreSQL)

For SQL Server:

SELECT TOP 5 * FROM employees;

4. Write a query to find duplicate records in a table.

Solution:

SELECT column1, column2, COUNT(*)
FROM table_name
GROUP BY column1, column2
HAVING COUNT(*) > 1;

5. How do you find employees who don’t belong to any department?

Solution:

SELECT * 
FROM employees
WHERE department_id IS NULL;

6. What is a JOIN, and write a query to fetch data using INNER JOIN.

Solution:
A JOIN combines rows from two or more tables based on a related column.

SELECT e.name, d.department_name
FROM employees e
INNER JOIN departments d ON e.department_id = d.id;

7. Write a query to find the total number of employees in each department.

Solution:

SELECT department_id, COUNT(*) AS total_employees
FROM employees
GROUP BY department_id;

8. How do you fetch the current date in SQL?

Solution:

SELECT CURRENT_DATE; -- MySQL/PostgreSQL
SELECT GETDATE();    -- SQL Server

9. Write a query to delete duplicate rows but keep one.

Solution:

WITH CTE AS (
  SELECT *, ROW_NUMBER() OVER (PARTITION BY column1, column2 ORDER BY id) AS rn
  FROM table_name
)
DELETE FROM CTE WHERE rn > 1;

10. What is a Common Table Expression (CTE), and how do you use it?

Solution:
A CTE is a temporary result set defined within a query.

WITH EmployeeCTE AS (
  SELECT department_id, COUNT(*) AS total_employees
  FROM employees
  GROUP BY department_id
)
SELECT * FROM EmployeeCTE WHERE total_employees > 10;

Hope it helps :)

#sql #dataanalysts

✅ Top 10 SQL Interview Questions

1️⃣ What is SQL and its types? 
SQL (Structured Query Language) is used to manage and manipulate databases. 
Types: DDL, DML, DCL, TCL 
Example: CREATE, SELECT, GRANT, COMMIT

2️⃣ Explain SQL constraints. 
Constraints ensure data integrity:
⦁ PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, CHECK

3️⃣ What is normalization? 
It's organizing data to reduce redundancy and improve integrity (1NF, 2NF, 3NF…).

4️⃣ Explain different types of JOINs with example.
⦁ INNER JOIN: Returns matching rows
⦁ LEFT JOIN: All from left + matching right rows
⦁ RIGHT JOIN: All from right + matching left rows
⦁ FULL JOIN: All rows from both tables

5️⃣ What is a subquery? Give example. 
A query inside another query:

SELECT name FROM employees
WHERE department_id = (SELECT id FROM departments WHERE name='Sales');

6️⃣ How to optimize slow queries? 
Use indexes, avoid SELECT *, use joins wisely, reduce nested queries.

7️⃣ What are aggregate functions? List examples. 
Functions that perform a calculation on a set of values: 
SUM(), COUNT(), AVG(), MIN(), MAX()

8️⃣ Explain SQL injection and prevention. 
A security vulnerability to manipulate queries. Prevent via parameterized queries, input validation.

9️⃣ How to find Nth highest salary without TOP/LIMIT?

SELECT DISTINCT salary FROM employees e1
WHERE N-1 = (SELECT COUNT(DISTINCT salary) FROM employees e2 WHERE e2.salary > e1.salary);

🔟 What is a stored procedure? 
A precompiled SQL program that can be executed to perform operations repeatedly.

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SQL Command Essentials: DDL, DML, DCL, TCL 🚀

● DDL (Data Definition Language) 
– CREATE: Make new tables/databases 
– ALTER: Modify table structure 
– DROP: Delete tables/databases 
– TRUNCATE: Remove all data, keep structure

● DML (Data Manipulation Language) 
– SELECT: Retrieve data 
– INSERT: Add data 
– UPDATE: Change data 
– DELETE: Remove data

● DCL (Data Control Language) 
– GRANT: Give access rights 
– REVOKE: Remove access rights

● TCL (Transaction Control Language) 
– COMMIT: Save changes 
– ROLLBACK: Undo changes 
– SAVEPOINT: Mark save point to rollback 
– BEGIN/END TRANSACTION: Start/end transactions

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Data Analytics project ideas to build your portfolio in 2025:

1. Sales Data Analysis Dashboard

Analyze sales trends, seasonal patterns, and product performance.

Use Power BI, Tableau, or Python (Dash/Plotly) for visualization.



2. Customer Segmentation

Use clustering (K-means, hierarchical) on customer data to identify groups.

Provide actionable marketing insights.



3. Social Media Sentiment Analysis

Analyze tweets or reviews using NLP to gauge public sentiment.

Visualize positive, negative, and neutral trends over time.



4. Churn Prediction Model

Analyze customer data to predict who might leave a service.

Use logistic regression, decision trees, or random forest.



5. Financial Data Analysis

Study stock prices, moving averages, and volatility.

Create an interactive dashboard with key metrics.



6. Healthcare Analytics

Analyze patient data for disease trends or hospital resource usage.

Use visualization to highlight key findings.



7. Website Traffic Analysis

Use Google Analytics data to identify user behavior patterns.

Suggest improvements for user engagement and conversion.



8. Employee Attrition Analysis

Analyze HR data to find factors leading to employee turnover.

Use statistical tests and visualization.


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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 😊