Planning for Data Science or Data Engineering Interview.
Focus on SQL & Python first. Here are some important questions which you should know.
๐๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐๐๐ ๐ช๐ฎ๐๐ฌ๐ญ๐ข๐จ๐ง๐ฌ
1- Find out nth Order/Salary from the tables.
2- Find the no of output records in each join from given Table 1 & Table 2
3- YOY,MOM Growth related questions.
4- Find out Employee ,Manager Hierarchy (Self join related question) or
Employees who are earning more than managers.
5- RANK,DENSERANK related questions
6- Some row level scanning medium to complex questions using CTE or recursive CTE, like (Missing no /Missing Item from the list etc.)
7- No of matches played by every team or Source to Destination flight combination using CROSS JOIN.
8-Use window functions to perform advanced analytical tasks, such as calculating moving averages or detecting outliers.
9- Implement logic to handle hierarchical data, such as finding all descendants of a given node in a tree structure.
10-Identify and remove duplicate records from a table.
๐๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐๐ฒ๐ญ๐ก๐จ๐ง ๐ช๐ฎ๐๐ฌ๐ญ๐ข๐จ๐ง๐ฌ
1- Reversing a String using an Extended Slicing techniques.
2- Count Vowels from Given words .
3- Find the highest occurrences of each word from string and sort them in order.
4- Remove Duplicates from List.
5-Sort a List without using Sort keyword.
6-Find the pair of numbers in this list whose sum is n no.
7-Find the max and min no in the list without using inbuilt functions.
8-Calculate the Intersection of Two Lists without using Built-in Functions
9-Write Python code to make API requests to a public API (e.g., weather API) and process the JSON response.
10-Implement a function to fetch data from a database table, perform data manipulation, and update the database.
Join for more: https://t.iss.one/datasciencefun
ENJOY LEARNING ๐๐
Focus on SQL & Python first. Here are some important questions which you should know.
๐๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐๐๐ ๐ช๐ฎ๐๐ฌ๐ญ๐ข๐จ๐ง๐ฌ
1- Find out nth Order/Salary from the tables.
2- Find the no of output records in each join from given Table 1 & Table 2
3- YOY,MOM Growth related questions.
4- Find out Employee ,Manager Hierarchy (Self join related question) or
Employees who are earning more than managers.
5- RANK,DENSERANK related questions
6- Some row level scanning medium to complex questions using CTE or recursive CTE, like (Missing no /Missing Item from the list etc.)
7- No of matches played by every team or Source to Destination flight combination using CROSS JOIN.
8-Use window functions to perform advanced analytical tasks, such as calculating moving averages or detecting outliers.
9- Implement logic to handle hierarchical data, such as finding all descendants of a given node in a tree structure.
10-Identify and remove duplicate records from a table.
๐๐ฆ๐ฉ๐จ๐ซ๐ญ๐๐ง๐ญ ๐๐ฒ๐ญ๐ก๐จ๐ง ๐ช๐ฎ๐๐ฌ๐ญ๐ข๐จ๐ง๐ฌ
1- Reversing a String using an Extended Slicing techniques.
2- Count Vowels from Given words .
3- Find the highest occurrences of each word from string and sort them in order.
4- Remove Duplicates from List.
5-Sort a List without using Sort keyword.
6-Find the pair of numbers in this list whose sum is n no.
7-Find the max and min no in the list without using inbuilt functions.
8-Calculate the Intersection of Two Lists without using Built-in Functions
9-Write Python code to make API requests to a public API (e.g., weather API) and process the JSON response.
10-Implement a function to fetch data from a database table, perform data manipulation, and update the database.
Join for more: https://t.iss.one/datasciencefun
ENJOY LEARNING ๐๐
โค4
Step-by-Step Roadmap to Learn Data Science in 2025:
Step 1: Understand the Role
A data scientist in 2025 is expected to:
Analyze data to extract insights
Build predictive models using ML
Communicate findings to stakeholders
Work with large datasets in cloud environments
Step 2: Master the Prerequisite Skills
A. Programming
Learn Python (must-have): Focus on pandas, numpy, matplotlib, seaborn, scikit-learn
R (optional but helpful for statistical analysis)
SQL: Strong command over data extraction and transformation
B. Math & Stats
Probability, Descriptive & Inferential Statistics
Linear Algebra & Calculus (only what's necessary for ML)
Hypothesis testing
Step 3: Learn Data Handling
Data Cleaning, Preprocessing
Exploratory Data Analysis (EDA)
Feature Engineering
Tools: Python (pandas), Excel, SQL
Step 4: Master Machine Learning
Supervised Learning: Linear/Logistic Regression, Decision Trees, Random Forests, XGBoost
Unsupervised Learning: K-Means, Hierarchical Clustering, PCA
Deep Learning (optional): Use TensorFlow or PyTorch
Evaluation Metrics: Accuracy, AUC, Confusion Matrix, RMSE
Step 5: Learn Data Visualization & Storytelling
Python (matplotlib, seaborn, plotly)
Power BI / Tableau
Communicating insights clearly is as important as modeling
Step 6: Use Real Datasets & Projects
Work on projects using Kaggle, UCI, or public APIs
Examples:
Customer churn prediction
Sales forecasting
Sentiment analysis
Fraud detection
Step 7: Understand Cloud & MLOps (2025+ Skills)
Cloud: AWS (S3, EC2, SageMaker), GCP, or Azure
MLOps: Model deployment (Flask, FastAPI), CI/CD for ML, Docker basics
Step 8: Build Portfolio & Resume
Create GitHub repos with well-documented code
Post projects and blogs on Medium or LinkedIn
Prepare a data science-specific resume
Step 9: Apply Smartly
Focus on job roles like: Data Scientist, ML Engineer, Data Analyst โ DS
Use platforms like LinkedIn, Glassdoor, Hirect, AngelList, etc.
Practice data science interviews: case studies, ML concepts, SQL + Python coding
Step 10: Keep Learning & Updating
Follow top newsletters: Data Elixir, Towards Data Science
Read papers (arXiv, Google Scholar) on trending topics: LLMs, AutoML, Explainable AI
Upskill with certifications (Google Data Cert, Coursera, DataCamp, Udemy)
Free Resources to learn Data Science
Kaggle Courses: https://www.kaggle.com/learn
CS50 AI by Harvard: https://cs50.harvard.edu/ai/
Fast.ai: https://course.fast.ai/
Google ML Crash Course: https://developers.google.com/machine-learning/crash-course
Data Science Learning Series: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D/998
Data Science Books: https://t.iss.one/datalemur
React โค๏ธ for more
Step 1: Understand the Role
A data scientist in 2025 is expected to:
Analyze data to extract insights
Build predictive models using ML
Communicate findings to stakeholders
Work with large datasets in cloud environments
Step 2: Master the Prerequisite Skills
A. Programming
Learn Python (must-have): Focus on pandas, numpy, matplotlib, seaborn, scikit-learn
R (optional but helpful for statistical analysis)
SQL: Strong command over data extraction and transformation
B. Math & Stats
Probability, Descriptive & Inferential Statistics
Linear Algebra & Calculus (only what's necessary for ML)
Hypothesis testing
Step 3: Learn Data Handling
Data Cleaning, Preprocessing
Exploratory Data Analysis (EDA)
Feature Engineering
Tools: Python (pandas), Excel, SQL
Step 4: Master Machine Learning
Supervised Learning: Linear/Logistic Regression, Decision Trees, Random Forests, XGBoost
Unsupervised Learning: K-Means, Hierarchical Clustering, PCA
Deep Learning (optional): Use TensorFlow or PyTorch
Evaluation Metrics: Accuracy, AUC, Confusion Matrix, RMSE
Step 5: Learn Data Visualization & Storytelling
Python (matplotlib, seaborn, plotly)
Power BI / Tableau
Communicating insights clearly is as important as modeling
Step 6: Use Real Datasets & Projects
Work on projects using Kaggle, UCI, or public APIs
Examples:
Customer churn prediction
Sales forecasting
Sentiment analysis
Fraud detection
Step 7: Understand Cloud & MLOps (2025+ Skills)
Cloud: AWS (S3, EC2, SageMaker), GCP, or Azure
MLOps: Model deployment (Flask, FastAPI), CI/CD for ML, Docker basics
Step 8: Build Portfolio & Resume
Create GitHub repos with well-documented code
Post projects and blogs on Medium or LinkedIn
Prepare a data science-specific resume
Step 9: Apply Smartly
Focus on job roles like: Data Scientist, ML Engineer, Data Analyst โ DS
Use platforms like LinkedIn, Glassdoor, Hirect, AngelList, etc.
Practice data science interviews: case studies, ML concepts, SQL + Python coding
Step 10: Keep Learning & Updating
Follow top newsletters: Data Elixir, Towards Data Science
Read papers (arXiv, Google Scholar) on trending topics: LLMs, AutoML, Explainable AI
Upskill with certifications (Google Data Cert, Coursera, DataCamp, Udemy)
Free Resources to learn Data Science
Kaggle Courses: https://www.kaggle.com/learn
CS50 AI by Harvard: https://cs50.harvard.edu/ai/
Fast.ai: https://course.fast.ai/
Google ML Crash Course: https://developers.google.com/machine-learning/crash-course
Data Science Learning Series: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D/998
Data Science Books: https://t.iss.one/datalemur
React โค๏ธ for more
โค6๐1
Core data science concepts you should know:
๐ข 1. Statistics & Probability
Descriptive statistics: Mean, median, mode, standard deviation, variance
Inferential statistics: Hypothesis testing, confidence intervals, p-values, t-tests, ANOVA
Probability distributions: Normal, Binomial, Poisson, Uniform
Bayes' Theorem
Central Limit Theorem
๐ 2. Data Wrangling & Cleaning
Handling missing values
Outlier detection and treatment
Data transformation (scaling, encoding, normalization)
Feature engineering
Dealing with imbalanced data
๐ 3. Exploratory Data Analysis (EDA)
Univariate, bivariate, and multivariate analysis
Correlation and covariance
Data visualization tools: Matplotlib, Seaborn, Plotly
Insights generation through visual storytelling
๐ค 4. Machine Learning Fundamentals
Supervised Learning: Linear regression, logistic regression, decision trees, SVM, k-NN
Unsupervised Learning: K-means, hierarchical clustering, PCA
Model evaluation: Accuracy, precision, recall, F1-score, ROC-AUC
Cross-validation and overfitting/underfitting
Bias-variance tradeoff
๐ง 5. Deep Learning (Basics)
Neural networks: Perceptron, MLP
Activation functions (ReLU, Sigmoid, Tanh)
Backpropagation
Gradient descent and learning rate
CNNs and RNNs (intro level)
๐๏ธ 6. Data Structures & Algorithms (DSA)
Arrays, lists, dictionaries, sets
Sorting and searching algorithms
Time and space complexity (Big-O notation)
Common problems: string manipulation, matrix operations, recursion
๐พ 7. SQL & Databases
SELECT, WHERE, GROUP BY, HAVING
JOINS (inner, left, right, full)
Subqueries and CTEs
Window functions
Indexing and normalization
๐ฆ 8. Tools & Libraries
Python: pandas, NumPy, scikit-learn, TensorFlow, PyTorch
R: dplyr, ggplot2, caret
Jupyter Notebooks for experimentation
Git and GitHub for version control
๐งช 9. A/B Testing & Experimentation
Control vs. treatment group
Hypothesis formulation
Significance level, p-value interpretation
Power analysis
๐ 10. Business Acumen & Storytelling
Translating data insights into business value
Crafting narratives with data
Building dashboards (Power BI, Tableau)
Knowing KPIs and business metrics
React โค๏ธ for more
๐ข 1. Statistics & Probability
Descriptive statistics: Mean, median, mode, standard deviation, variance
Inferential statistics: Hypothesis testing, confidence intervals, p-values, t-tests, ANOVA
Probability distributions: Normal, Binomial, Poisson, Uniform
Bayes' Theorem
Central Limit Theorem
๐ 2. Data Wrangling & Cleaning
Handling missing values
Outlier detection and treatment
Data transformation (scaling, encoding, normalization)
Feature engineering
Dealing with imbalanced data
๐ 3. Exploratory Data Analysis (EDA)
Univariate, bivariate, and multivariate analysis
Correlation and covariance
Data visualization tools: Matplotlib, Seaborn, Plotly
Insights generation through visual storytelling
๐ค 4. Machine Learning Fundamentals
Supervised Learning: Linear regression, logistic regression, decision trees, SVM, k-NN
Unsupervised Learning: K-means, hierarchical clustering, PCA
Model evaluation: Accuracy, precision, recall, F1-score, ROC-AUC
Cross-validation and overfitting/underfitting
Bias-variance tradeoff
๐ง 5. Deep Learning (Basics)
Neural networks: Perceptron, MLP
Activation functions (ReLU, Sigmoid, Tanh)
Backpropagation
Gradient descent and learning rate
CNNs and RNNs (intro level)
๐๏ธ 6. Data Structures & Algorithms (DSA)
Arrays, lists, dictionaries, sets
Sorting and searching algorithms
Time and space complexity (Big-O notation)
Common problems: string manipulation, matrix operations, recursion
๐พ 7. SQL & Databases
SELECT, WHERE, GROUP BY, HAVING
JOINS (inner, left, right, full)
Subqueries and CTEs
Window functions
Indexing and normalization
๐ฆ 8. Tools & Libraries
Python: pandas, NumPy, scikit-learn, TensorFlow, PyTorch
R: dplyr, ggplot2, caret
Jupyter Notebooks for experimentation
Git and GitHub for version control
๐งช 9. A/B Testing & Experimentation
Control vs. treatment group
Hypothesis formulation
Significance level, p-value interpretation
Power analysis
๐ 10. Business Acumen & Storytelling
Translating data insights into business value
Crafting narratives with data
Building dashboards (Power BI, Tableau)
Knowing KPIs and business metrics
React โค๏ธ for more
โค15๐2
Data Analytics Interview Questions
1. What is the difference between SQL and MySQL?
SQL is a standard language for retrieving and manipulating structured databases. On the contrary, MySQL is a relational database management system, like SQL Server, Oracle or IBM DB2, that is used to manage SQL databases.
2. What is a Cross-Join?
Cross join can be defined as a cartesian product of the two tables included in the join. The table after join contains the same number of rows as in the cross-product of the number of rows in the two tables. If a WHERE clause is used in cross join then the query will work like an INNER JOIN.
3. What is a Stored Procedure?
A stored procedure is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary. The sole disadvantage of stored procedure is that it can be executed nowhere except in the database and occupies more memory in the database server.
4. What is Pattern Matching in SQL?
SQL pattern matching provides for pattern search in data if you have no clue as to what that word should be. This kind of SQL query uses wildcards to match a string pattern, rather than writing the exact word. The LIKE operator is used in conjunction with SQL Wildcards to fetch the required information.
1. What is the difference between SQL and MySQL?
SQL is a standard language for retrieving and manipulating structured databases. On the contrary, MySQL is a relational database management system, like SQL Server, Oracle or IBM DB2, that is used to manage SQL databases.
2. What is a Cross-Join?
Cross join can be defined as a cartesian product of the two tables included in the join. The table after join contains the same number of rows as in the cross-product of the number of rows in the two tables. If a WHERE clause is used in cross join then the query will work like an INNER JOIN.
3. What is a Stored Procedure?
A stored procedure is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary. The sole disadvantage of stored procedure is that it can be executed nowhere except in the database and occupies more memory in the database server.
4. What is Pattern Matching in SQL?
SQL pattern matching provides for pattern search in data if you have no clue as to what that word should be. This kind of SQL query uses wildcards to match a string pattern, rather than writing the exact word. The LIKE operator is used in conjunction with SQL Wildcards to fetch the required information.
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