Best practices for writing SQL queries:

Join for more: https://t.iss.one/learndataanalysis

1- Write SQL keywords in capital letters.

2- Use table aliases with columns when you are joining multiple tables.

3- Never use select *, always mention list of columns in select clause.

4- Add useful comments wherever you write complex logic. Avoid too many comments.

5- Use joins instead of subqueries when possible for better performance.

6- Create CTEs instead of multiple sub queries , it will make your query easy to read.

7- Join tables using JOIN keywords instead of writing join condition in where clause for better readability.

8- Never use order by in sub queries , It will unnecessary increase runtime.

9- If you know there are no duplicates in 2 tables, use UNION ALL instead of UNION for better performance.

SQL Basics: https://t.iss.one/sqlanalyst/105

𝗛𝗼𝘄 𝘁𝗼 𝗕𝗲𝗰𝗼𝗺𝗲 𝗮 𝗝𝗼𝗯-𝗥𝗲𝗮𝗱𝘆 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝘁𝗶𝘀𝘁 𝗳𝗿𝗼𝗺 𝗦𝗰𝗿𝗮𝘁𝗰𝗵 (𝗘𝘃𝗲𝗻 𝗶𝗳 𝗬𝗼𝘂’𝗿𝗲 𝗮 𝗕𝗲𝗴𝗶𝗻𝗻𝗲𝗿!) 📊

Wanna break into data science but feel overwhelmed by too many courses, buzzwords, and conflicting advice? You’re not alone.

Here’s the truth: You don’t need a PhD or 10 certifications. You just need the right skills in the right order.

Let me show you a proven 5-step roadmap that actually works for landing data science roles (even entry-level) 👇

🔹 Step 1: Learn the Core Tools (This is Your Foundation)

Focus on 3 key tools first—don’t overcomplicate:

✅ Python – NumPy, Pandas, Matplotlib, Seaborn
✅ SQL – Joins, Aggregations, Window Functions
✅ Excel – VLOOKUP, Pivot Tables, Data Cleaning

🔹 Step 2: Master Data Cleaning & EDA (Your Real-World Skill)

Real data is messy. Learn how to:

✅ Handle missing data, outliers, and duplicates
✅ Visualize trends using Matplotlib/Seaborn
✅ Use groupby(), merge(), and pivot_table()

🔹 Step 3: Learn ML Basics (No Fancy Math Needed)

Stick to core algorithms first:

✅ Linear & Logistic Regression
✅ Decision Trees & Random Forest
✅ KMeans Clustering + Model Evaluation Metrics

🔹 Step 4: Build Projects That Prove Your Skills

One strong project > 5 courses. Create:

✅ Sales Forecasting using Time Series
✅ Movie Recommendation System
✅ HR Analytics Dashboard using Python + Excel
📍 Upload them on GitHub. Add visuals, write a good README, and share on LinkedIn.

🔹 Step 5: Prep for the Job Hunt (Your Personal Brand Matters)

✅ Create a strong LinkedIn profile with keywords like “Aspiring Data Scientist | Python | SQL | ML”
✅ Add GitHub link + Highlight your Projects
✅ Follow Data Science mentors, engage with content, and network for referrals

🎯 No shortcuts. Just consistent baby steps.

Every pro data scientist once started as a beginner. Stay curious, stay consistent.

Free Data Science Resources: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D

ENJOY LEARNING 👍👍

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Machine learning powers so many things around us – from recommendation systems to self-driving cars!

But understanding the different types of algorithms can be tricky.

This is a quick and easy guide to the four main categories: Supervised, Unsupervised, Semi-Supervised, and Reinforcement Learning.

𝟏. 𝐒𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠
In supervised learning, the model learns from examples that already have the answers (labeled data). The goal is for the model to predict the correct result when given new data.

𝐒𝐨𝐦𝐞 𝐜𝐨𝐦𝐦𝐨𝐧 𝐬𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐥𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐚𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦𝐬 𝐢𝐧𝐜𝐥𝐮𝐝𝐞:

➡️ Linear Regression – For predicting continuous values, like house prices.
➡️ Logistic Regression – For predicting categories, like spam or not spam.
➡️ Decision Trees – For making decisions in a step-by-step way.
➡️ K-Nearest Neighbors (KNN) – For finding similar data points.
➡️ Random Forests – A collection of decision trees for better accuracy.
➡️ Neural Networks – The foundation of deep learning, mimicking the human brain.

𝟐. 𝐔𝐧𝐬𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠
With unsupervised learning, the model explores patterns in data that doesn’t have any labels. It finds hidden structures or groupings.

𝐒𝐨𝐦𝐞 𝐩𝐨𝐩𝐮𝐥𝐚𝐫 𝐮𝐧𝐬𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐥𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐚𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦𝐬 𝐢𝐧𝐜𝐥𝐮𝐝𝐞:

➡️ K-Means Clustering – For grouping data into clusters.
➡️ Hierarchical Clustering – For building a tree of clusters.
➡️ Principal Component Analysis (PCA) – For reducing data to its most important parts.
➡️ Autoencoders – For finding simpler representations of data.

𝟑. 𝐒𝐞𝐦𝐢-𝐒𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠
This is a mix of supervised and unsupervised learning. It uses a small amount of labeled data with a large amount of unlabeled data to improve learning.

𝐂𝐨𝐦𝐦𝐨𝐧 𝐬𝐞𝐦𝐢-𝐬𝐮𝐩𝐞𝐫𝐯𝐢𝐬𝐞𝐝 𝐥𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐚𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦𝐬 𝐢𝐧𝐜𝐥𝐮𝐝𝐞:

➡️ Label Propagation – For spreading labels through connected data points.
➡️ Semi-Supervised SVM – For combining labeled and unlabeled data.
➡️ Graph-Based Methods – For using graph structures to improve learning.

𝟒. 𝐑𝐞𝐢𝐧𝐟𝐨𝐫𝐜𝐞𝐦𝐞𝐧𝐭 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠
In reinforcement learning, the model learns by trial and error. It interacts with its environment, receives feedback (rewards or penalties), and learns how to act to maximize rewards.

𝐏𝐨𝐩𝐮𝐥𝐚𝐫 𝐫𝐞𝐢𝐧𝐟𝐨𝐫𝐜𝐞𝐦𝐞𝐧𝐭 𝐥𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐚𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦𝐬 𝐢𝐧𝐜𝐥𝐮𝐝𝐞:

➡️ Q-Learning – For learning the best actions over time.
➡️ Deep Q-Networks (DQN) – Combining Q-learning with deep learning.
➡️ Policy Gradient Methods – For learning policies directly.
➡️ Proximal Policy Optimization (PPO) – For stable and effective learning.

ENJOY LEARNING 👍👍

Essential statistics topics for data science

1. Descriptive statistics: Measures of central tendency, measures of dispersion, and graphical representations of data.

2. Inferential statistics: Hypothesis testing, confidence intervals, and regression analysis.

3. Probability theory: Concepts of probability, random variables, and probability distributions.

4. Sampling techniques: Simple random sampling, stratified sampling, and cluster sampling.

5. Statistical modeling: Linear regression, logistic regression, and time series analysis.

6. Machine learning algorithms: Supervised learning, unsupervised learning, and reinforcement learning.

7. Bayesian statistics: Bayesian inference, Bayesian networks, and Markov chain Monte Carlo methods.

8. Data visualization: Techniques for visualizing data and communicating insights effectively.

9. Experimental design: Designing experiments, analyzing experimental data, and interpreting results.

10. Big data analytics: Handling large volumes of data using tools like Hadoop, Spark, and SQL.

Best Data Science & Machine Learning Resources: https://topmate.io/coding/914624

Credits: https://t.iss.one/datasciencefun

Like if you need similar content 😄👍

Accenture Data Scientist Interview Questions!

1st round-

Technical Round

- 2 SQl questions based on playing around views and table, which could be solved by both subqueries and window functions.

- 2 Pandas questions , testing your knowledge on filtering , concatenation , joins and merge.

- 3-4 Machine Learning questions completely based on my Projects, starting from
Explaining the problem statements and then discussing the roadblocks of those projects and some cross questions.

2nd round-

- Couple of python questions agains on pandas and numpy and some hypothetical data.

- Machine Learning projects explanations and cross questions.

- Case Study and a quiz question.

3rd and Final round.

HR interview

Simple Scenerio Based Questions.

Data Science Resources
👇👇
https://t.iss.one/datasciencefun

Like if you need similar content 😄👍

🚀 𝗛𝗼𝘄 𝘁𝗼 𝗕𝘂𝗶𝗹𝗱 𝗮 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗣𝗼𝗿𝘁𝗳𝗼𝗹𝗶𝗼 𝗧𝗵𝗮𝘁 𝗧𝗿𝘂𝗹𝘆 𝗦𝘁𝗮𝗻𝗱𝘀 𝗢𝘂𝘁

In today’s competitive landscape, a strong resume alone won't get you far. If you're aiming for 𝘆𝗼𝘂𝗿 𝗱𝗿𝗲𝗮𝗺 𝗱𝗮𝘁𝗮 𝘀𝗰𝗶𝗲𝗻𝗰𝗲 𝗿𝗼𝗹𝗲, you need a portfolio that speaks volumes—one that highlights your skills, thinking process, and real-world impact.

A great portfolio isn’t just a collection of projects. It’s your story as a data scientist—and here’s how to make it unforgettable:

🔹 𝗪𝗵𝗮𝘁 𝗠𝗮𝗸𝗲𝘀 𝗮𝗻 𝗘𝘅𝗰𝗲𝗽𝘁𝗶𝗼𝗻𝗮𝗹 𝗣𝗼𝗿𝘁𝗳𝗼𝗹𝗶𝗼?

✅ Quality Over Quantity – A few impactful projects are far better than a dozen generic ones.

✅ Tell a Story – Clearly explain the problem, your approach, and key insights. Keep it engaging.

✅ Show Range – Demonstrate a variety of skills—data cleaning, visualization, analytics, modeling.

✅ Make It Relevant – Choose projects with real-world business value, not just toy Kaggle datasets.

🔥 𝗣𝗿𝗼𝗷𝗲𝗰𝘁 𝗜𝗱𝗲𝗮𝘀 𝗧𝗵𝗮𝘁 𝗥𝗲𝗰𝗿𝘂𝗶𝘁𝗲𝗿𝘀 𝗡𝗼𝘁𝗶𝗰𝗲

1️⃣ Customer Churn Prediction – Help businesses retain customers through insights.

2️⃣ Social Media Sentiment Analysis – Extract opinions from real-time data like tweets or reviews.

3️⃣ Supply Chain Optimization – Solve efficiency problems using operational data.

4️⃣ E-commerce Recommender System – Personalize shopping experiences with smart suggestions.

5️⃣ Interactive Dashboards – Use Power BI or Tableau to tell compelling visual stories.

📌 𝗕𝗲𝘀𝘁 𝗣𝗿𝗮𝗰𝘁𝗶𝗰𝗲𝘀 𝗳𝗼𝗿 𝗮 𝗞𝗶𝗹𝗹𝗲𝗿 𝗣𝗼𝗿𝘁𝗳𝗼𝗹𝗶𝗼

💡 Host on GitHub – Keep your code clean, well-structured, and documented.

💡 Write About It – Use Medium or your own site to explain your projects and decisions.

💡 Deploy Your Work – Use tools like Streamlit, Flask, or FastAPI to make your projects interactive.

💡 Open Source Contributions – It’s a great way to gain credibility and connect with others.

A great data science portfolio is not just about code—it's about solving real problems with data.

Free Data Science Resources: https://t.iss.one/datalemur

All the best 👍👍

​​Python Learning Courses provided by Microsoft 📚

Recently, I found out that Microsoft provides quality online courses related to Python on Microsoft Learn.
Microsoft Learn is a free online platform that provides access to a set of training courses for the acquisition and improvement of digital skills. Each course is designed as a module, each module contains different lessons and exercises. Below are the modules related to Python learning.

🟢Beginner
1. What is Python?
2. Introduction to Python
3. Take your first steps with Python
4. Set up your Python beginner development environment with Visual Studio Code
5. Branch code execution with the if...elif...else statement in Python
6. Manipulate and format string data for display in Python
7. Perform mathematical operations on numeric data in Python
8. Iterate through code blocks by using the while statement
9. Import standard library modules to add features to Python programs
10. Create reusable functionality with functions in Python
11. Manage a sequence of data by using Python lists
12. Write basic Python in Notebooks
13. Count the number of Moon rocks by type using Python
14. Code control statements in Python
15. Introduction to Python for space exploration
16. Install coding tools for Python development
17. Discover the role of Python in space exploration
18. Crack the code and reveal a secret with Python and Visual Studio Code
19. Introduction to object-oriented programming with Python
20. Use Python basics to solve mysteries and find answers
21. Predict meteor showers by using Python and Visual Studio Code
22. Plan a Moon mission by using Python pandas

🟠Intermediate
1. Create machine learning models
2. Explore and analyze data with Python
3. Build an AI web app by using Python and Flask
4. Get started with Django
5. Architect full-stack applications and automate deployments with GitHub

#materials