Data Science & Machine Learning
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Data Science Cheatsheet πŸ’ͺ
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Top 20 AI Concepts You Should Know

1 - Machine Learning: Core algorithms, statistics, and model training techniques.
2 - Deep Learning: Hierarchical neural networks learning complex representations automatically.
3 - Neural Networks: Layered architectures efficiently model nonlinear relationships accurately.
4 - NLP: Techniques to process and understand natural language text.
5 - Computer Vision: Algorithms interpreting and analyzing visual data effectively
6 - Reinforcement Learning: Distributed traffic across multiple servers for reliability.
7 - Generative Models: Creating new data samples using learned data.
8 - LLM: Generates human-like text using massive pre-trained data.
9 - Transformers: Self-attention-based architecture powering modern AI models.
10 - Feature Engineering: Designing informative features to improve model performance significantly.
11 - Supervised Learning: Learns useful representations without labeled data.
12 - Bayesian Learning: Incorporate uncertainty using probabilistic model approaches.
13 - Prompt Engineering: Crafting effective inputs to guide generative model outputs.
14 - AI Agents: Autonomous systems that perceive, decide, and act.
15 - Fine-Tuning Models: Customizes pre-trained models for domain-specific tasks.
16 - Multimodal Models: Processes and generates across multiple data types like images, videos, and text.
17 - Embeddings: Transforms input into machine-readable vector formats.
18 - Vector Search: Finds similar items using dense vector embeddings.
19 - Model Evaluation: Assessing predictive performance using validation techniques.
20 - AI Infrastructure: Deploying scalable systems to support AI operations.

Artificial intelligence Resources: https://whatsapp.com/channel/0029VaoePz73bbV94yTh6V2E

AI Jobs: https://whatsapp.com/channel/0029VaxtmHsLikgJ2VtGbu1R

Hope this helps you ☺️
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When preparing for an SQL project-based interview, the focus typically shifts from theoretical knowledge to practical application. Here are some SQL project-based interview questions that could help assess your problem-solving skills and experience:

1. Database Design and Schema
- Question: Describe a database schema you have designed in a past project. What were the key entities, and how did you establish relationships between them?
- Follow-Up: How did you handle normalization? Did you denormalize any tables for performance reasons?

2. Data Modeling
- Question: How would you model a database for an e-commerce application? What tables would you include, and how would they relate to each other?
- Follow-Up: How would you design the schema to handle scenarios like discount codes, product reviews, and inventory management?

3. Query Optimization
- Question: Can you discuss a time when you optimized an SQL query? What was the original query, and what changes did you make to improve its performance?
- Follow-Up: What tools or techniques did you use to identify and resolve the performance issues?

4. ETL Processes
- Question: Describe an ETL (Extract, Transform, Load) process you have implemented. How did you handle data extraction, transformation, and loading?
- Follow-Up: How did you ensure data quality and consistency during the ETL process?

5. Handling Large Datasets
- Question: In a project where you dealt with large datasets, how did you manage performance and storage issues?
- Follow-Up: What indexing strategies or partitioning techniques did you use?

6. Joins and Subqueries
- Question: Provide an example of a complex query you wrote involving multiple joins and subqueries. What was the business problem you were solving?
- Follow-Up: How did you ensure that the query performed efficiently?

7. Stored Procedures and Functions
- Question: Have you created stored procedures or functions in any of your projects? Can you describe one and explain why you chose to encapsulate the logic in a stored procedure?
- Follow-Up: How did you handle error handling and logging within the stored procedure?

8. Data Integrity and Constraints
- Question: How did you enforce data integrity in your SQL projects? Can you give examples of constraints (e.g., primary keys, foreign keys, unique constraints) you implemented?
- Follow-Up: How did you handle situations where constraints needed to be temporarily disabled or modified?

9. Version Control and Collaboration
- Question: How did you manage database version control in your projects? What tools or practices did you use to ensure collaboration with other developers?
- Follow-Up: How did you handle conflicts or issues arising from multiple developers working on the same database?

10. Data Migration
- Question: Describe a data migration project you worked on. How did you ensure that the migration was successful, and what steps did you take to handle data inconsistencies or errors?
- Follow-Up: How did you test the migration process before moving to the production environment?

11. Security and Permissions
- Question: In your SQL projects, how did you manage database security?
- Follow-Up: How did you handle encryption or sensitive data within the database?

12. Handling Unstructured Data
- Question: Have you worked with unstructured or semi-structured data in an SQL environment?
- Follow-Up: What challenges did you face, and how did you overcome them?

13. Real-Time Data Processing
   - Question: Can you describe a project where you handled real-time data processing using SQL? What were the key challenges, and how did you address them?
   - Follow-Up: How did you ensure the performance and reliability of the real-time data processing system?

Be prepared to discuss specific examples from your past work and explain your thought process in detail.

Here you can find SQL Interview ResourcesπŸ‘‡
https://t.iss.one/DataSimplifier

Share with credits: https://t.iss.one/sqlspecialist

Hope it helps :)
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Tableau Cheat Sheet βœ…

This Tableau cheatsheet is designed to be your quick reference guide for data visualization and analysis using Tableau. Whether you’re a beginner learning the basics or an experienced user looking for a handy resource, this cheatsheet covers essential topics.

1. Connecting to Data
   - Use *Connect* pane to connect to various data sources (Excel, SQL Server, Text files, etc.).

2. Data Preparation
   - Data Interpreter: Clean data automatically using the Data Interpreter.
   - Join Data: Combine data from multiple tables using joins (Inner, Left, Right, Outer).
   - Union Data: Stack data from multiple tables with the same structure.

3. Creating Views
   - Drag & Drop: Drag fields from the Data pane onto Rows, Columns, or Marks to create visualizations.
   - Show Me: Use the *Show Me* panel to select different visualization types.

4. Types of Visualizations
   - Bar Chart: Compare values across categories.
   - Line Chart: Display trends over time.
   - Pie Chart: Show proportions of a whole (use sparingly).
   - Map: Visualize geographic data.
   - Scatter Plot: Show relationships between two variables.

5. Filters
   - Dimension Filters: Filter data based on categorical values.
   - Measure Filters: Filter data based on numerical values.
   - Context Filters: Set a context for other filters to improve performance.

6. Calculated Fields
   - Create calculated fields to derive new data:
     - Example: Sales Growth = SUM([Sales]) - SUM([Previous Sales])

7. Parameters
   - Use parameters to allow user input and control measures dynamically.

8. Formatting
   - Format fonts, colors, borders, and lines using the Format pane for better visual appeal.

9. Dashboards
   - Combine multiple sheets into a dashboard using the *Dashboard* tab.
   - Use dashboard actions (filter, highlight, URL) to create interactivity.

10. Story Points
    - Create a story to guide users through insights with narrative and visualizations.

11. Publishing & Sharing
    - Publish dashboards to Tableau Server or Tableau Online for sharing and collaboration.

12. Export Options
    - Export to PDF or image for offline use.

13. Keyboard Shortcuts
    - Show/Hide Sidebar: Ctrl+Alt+T
    - Duplicate Sheet: Ctrl + D
    - Undo: Ctrl + Z
    - Redo: Ctrl + Y

14. Performance Optimization
    - Use extracts instead of live connections for faster performance.
    - Optimize calculations and filters to improve dashboard loading times.

Best Resources to learn Tableau: https://whatsapp.com/channel/0029VasYW1V5kg6z4EHOHG1t

Hope you'll like it

Share with credits: https://t.iss.one/sqlspecialist

Hope it helps :)
SQL interview questions with answers πŸ˜„πŸ‘‡

1. Question: What is SQL?

   Answer: SQL (Structured Query Language) is a programming language designed for managing and manipulating relational databases. It is used to query, insert, update, and delete data in databases.

2. Question: Differentiate between SQL and MySQL.

   Answer: SQL is a language for managing relational databases, while MySQL is an open-source relational database management system (RDBMS) that uses SQL as its language.

3. Question: Explain the difference between INNER JOIN and LEFT JOIN.

   Answer: INNER JOIN returns rows when there is a match in both tables, while LEFT JOIN returns all rows from the left table and the matched rows from the right table, filling in with NULLs for non-matching rows.

4. Question: How do you remove duplicate records from a table?

   Answer: Use the DISTINCT keyword in a SELECT statement to retrieve unique records. For example: SELECT DISTINCT column1, column2 FROM table;

5. Question: What is a subquery in SQL?

   Answer: A subquery is a query nested inside another query. It can be used to retrieve data that will be used in the main query as a condition to further restrict the data to be retrieved.

6. Question: Explain the purpose of the GROUP BY clause.

   Answer: The GROUP BY clause is used to group rows that have the same values in specified columns into summary rows, like when using aggregate functions such as COUNT, SUM, AVG, etc.

7. Question: How can you add a new record to a table?

   Answer: Use the INSERT INTO statement. For example: INSERT INTO table_name (column1, column2) VALUES (value1, value2);

8. Question: What is the purpose of the HAVING clause?

   Answer: The HAVING clause is used in combination with the GROUP BY clause to filter the results of aggregate functions based on a specified condition.

9. Question: Explain the concept of normalization in databases.

   Answer: Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. It involves breaking down tables into smaller, related tables.

10. Question: How do you update data in a table in SQL?

    Answer: Use the UPDATE statement to modify existing records in a table. For example: UPDATE table_name SET column1 = value1 WHERE condition;
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30 Days Python Roadmap for Data Analysts πŸ‘†
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Data Analyst Roadmap

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