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Data science interview questions ๐Ÿ‘‡

๐—ฆ๐—ค๐—Ÿ
- How do you write a query to fetch the top 5 highest salaries in each department?
- Whatโ€™s the difference between the HAVING and WHERE clauses in SQL?
- How do you handle NULL values in SQL, and how do they affect aggregate functions?

๐—ฃ๐˜†๐˜๐—ต๐—ผ๐—ป
- How do you handle large datasets in Python, and which libraries would you use for performance?
- What are context managers in Python, and how do they help with resource management?
- How do you manage and log errors in Python-based ETL pipelines?

๐— ๐—ฎ๐—ฐ๐—ต๐—ถ๐—ป๐—ฒ ๐—Ÿ๐—ฒ๐—ฎ๐—ฟ๐—ป๐—ถ๐—ป๐—ด
- Explain the difference between bias and variance in a machine learning model. How do you balance them?
- What is cross-validation, and how does it improve the performance of machine learning models?
- How do you deal with class imbalance in classification tasks, and what techniques would you apply?

๐——๐—ฒ๐—ฒ๐—ฝ ๐—Ÿ๐—ฒ๐—ฎ๐—ฟ๐—ป๐—ถ๐—ป๐—ด
- What is the vanishing gradient problem in deep learning, and how can it be mitigated?
- Explain how a convolutional neural network (CNN) works and when you would use it.
- What is dropout in neural networks, and how does it help prevent overfitting?

๐——๐—ฎ๐˜๐—ฎ ๐—ช๐—ฟ๐—ฎ๐—ป๐—ด๐—น๐—ถ๐—ป๐—ด
- How would you handle outliers in a dataset, and when is it appropriate to remove or keep them?
- Explain how to merge two datasets in Python, and how would you handle duplicate or missing entries in the merged data?
- What is data normalization, and when should you apply it to your dataset?

๐——๐—ฎ๐˜๐—ฎ ๐—ฉ๐—ถ๐˜€๐˜‚๐—ฎ๐—น๐—ถ๐˜‡๐—ฎ๐˜๐—ถ๐—ผ๐—ป - ๐—ง๐—ฎ๐—ฏ๐—น๐—ฒ๐—ฎ๐˜‚
- How do you create a dual-axis chart in Tableau, and when would you use it?
- How would you filter data in Tableau to create a dynamic dashboard that updates based on user input?
- What are calculated fields in Tableau, and how would you use them to create a custom metric?

#datascience #interview
Learning Python has never been this engaging! ๐Ÿ”๐ŸŸ๐Ÿง‹

๐Ÿ‘‰ Learn Python ZERO TO HERO
๐Ÿ”ฅ 7000+ Free Courses | Free Access:
๐Ÿ”— https://freecoderzone.blogspot.com/2025/01/7000-free-courses.html

๐Ÿ“˜ Top Python Learning Resources:

1๏ธโƒฃ Python for Everybody Specialization
๐Ÿ”— https://www.coursera.org/specializations/python

2๏ธโƒฃ Crash Course on Python
๐Ÿ”— https://www.coursera.org/learn/python-crash-course

3๏ธโƒฃ Get Started with Python
๐Ÿ”— https://developer.mozilla.org/en-US/docs/Learn/Server-side/Python/Introduction

4๏ธโƒฃ Python for Data Science, AI & Development
๐Ÿ”— https://www.edx.org/course/python-for-data-science-ai-development

5๏ธโƒฃ Google Data Analytics
๐Ÿ”— https://www.coursera.org/professional-certificates/google-data-analytics

6๏ธโƒฃ Google Advanced Data Analytics
๐Ÿ”— https://www.coursera.org/professional-certificates/google-advanced-data-analytics

7๏ธโƒฃ IBM Data Science Professional Certificate
๐Ÿ”— https://www.coursera.org/professional-certificates/ibm-data-science

8๏ธโƒฃ IBM Data Warehouse Engineer Professional Certificate
๐Ÿ”— https://www.coursera.org/professional-certificates/ibm-data-warehouse-engineer

9๏ธโƒฃ IBM Cybersecurity Analyst Professional Certificate
๐Ÿ”— https://www.coursera.org/professional-certificates/ibm-cybersecurity-analyst

๐Ÿ”Ÿ IBM AI Engineering Professional Certificate
๐Ÿ”— https://www.coursera.org/professional-certificates/ai-engineering

1๏ธโƒฃ1๏ธโƒฃ IBM DevOps and Software Engineering Professional Certificate
๐Ÿ”— https://www.coursera.org/professional-certificates/ibm-devops-and-software-engineering


Letโ€™s make Python learning fun and interactive! ๐Ÿš€
#Python #LearnPython #Programming #CodingSkills #DataScience
7 Best GitHub Repositories to Break into Data Analytics and Data Science

If you're diving into data science or data analytics, these repositories will give you the edge you need. Check them out:

1๏ธโƒฃ 100-Days-Of-ML-Code
๐Ÿ”— https://github.com/Avik-Jain/100-Days-Of-ML-Code
โญ๏ธ Stars: ~42k

2๏ธโƒฃ awesome-datascience
๐Ÿ”— https://github.com/academic/awesome-datascience
โญ๏ธ Stars: ~22.7k

3๏ธโƒฃ Data-Science-For-Beginners
๐Ÿ”— https://github.com/microsoft/Data-Science-For-Beginners
โญ๏ธ Stars: ~14.5k

4๏ธโƒฃ data-science-interviews
๐Ÿ”— https://github.com/alexeygrigorev/data-science-interviews
โญ๏ธ Stars: ~5.8k

5๏ธโƒฃ Coding and ML System Design
๐Ÿ”— https://github.com/weeeBox/coding-and-ml-system-design
โญ๏ธ Stars: ~3.5k

6๏ธโƒฃ Machine Learning Interviews from MAANG
๐Ÿ”— https://github.com/arunkumarpillai/Machine-Learning-Interviews
โญ๏ธ Stars: ~8.1k

7๏ธโƒฃ data-science-ipython-notebooks
๐Ÿ”— https://github.com/donnemartin/data-science-ipython-notebooks
โญ๏ธ Stars: ~27.2k

Explore these amazing resources and take your data science journey to the next level! ๐Ÿš€
#DataScience #DataAnalytics #GitHub #MachineLearning #CodingSkills
Provides a default value for a column when no value is specified.
โœ”๏ธ Helps in avoiding NULL values in columns where default values make sense.

โœ… Example of DEFAULT Constraint
CREATE TABLE Orders (
OrderID INT PRIMARY KEY,
CustomerName VARCHAR(50),
OrderDate DATE DEFAULT CURRENT_DATE
);

โœ”๏ธ If OrderDate is not provided, it automatically gets the current date.

โœ… Inserting Data (Valid Cases)
INSERT INTO Orders (OrderID, CustomerName) VALUES (1, 'Alice'); -- โœ… OrderDate is set to today's date
INSERT INTO Orders (OrderID, CustomerName, OrderDate) VALUES (2, 'Bob', '2025-01-01'); -- โœ… Valid, custom date given


---

๐Ÿ”น Summary of SQL Constraints

| Constraint | Ensures | Can Be NULL? | Allows Multiple in a Table? |
|--------------|---------------------------------|--------------|--------------------------|
| PRIMARY KEY | Uniqueness & Non-null values | โŒ No | โŒ No (Only One) |
| FOREIGN KEY | Referential Integrity | โœ… Yes (If NULL allowed) | โœ… Yes |
| UNIQUE | Uniqueness (without Primary Key) | โœ… Yes | โœ… Yes |
| CHECK | Enforces condition on values | โœ… Yes | โœ… Yes |
| DEFAULT | Provides a default value | โœ… Yes | โœ… Yes |

---

๐Ÿ”น Your Task for Today
โœ… Create a Students & Courses database using all the constraints.
โœ… Try inserting valid & invalid values to see how constraints work.
โœ… Comment below if you have any questions! ๐Ÿ’ฌ

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๐Ÿ”น Whatโ€™s Next?
Tomorrow, we will learn Creating and Managing Indexes! Stay tuned! ๐Ÿš€

๐Ÿ’ก Like โค๏ธ & Share if you're enjoying this SQL series! ๐Ÿ˜Š

#DataScience #DataScience #DataAnalytics
To be GOOD in Data Science you need to learn:

- Python
- SQL
- PowerBI

To be GREAT in Data Science you need to add:

- Business Understanding
- Knowledge of Cloud
- Many-many projects

But to LAND a job in Data Science you need to prove you can:

- Learn new things
- Communicate clearly
- Solve problems

#DataScience #LearnPython