Anuj Saini
Founder & Lead InstructorFounder & Data Analytics Lead
Founder at Topfolio with 6+ years in data & analytics across JPMC, Ultrahuman, and high-growth startups. Sat on hiring panels, reviewed 500+ resumes, and writes practical SQL & data guides.
Articles by Anuj Saini
170 guides & tutorials published
10-Point Resume Scorecard
Grade your analyst resume the way hiring managers do: 10 checks with honest score bands, plus exactly where to start fixing a failing screen first.
Analyst Cohort Readiness Check
A 5-question self-gate before joining any analyst cohort: score 4 or more and you are ready, otherwise follow the exact free starting points inside.
5 Window Traps That Lie
Basket-split LAG gaps, ghost orders, nondeterministic ROW_NUMBER, RANK gaps, unframed running totals: 5 window traps with fixes and SQL included.
30 SQL Interview Questions, Free
The 30 SQL patterns analyst interviews repeat — JOINs, windows, GROUP BY traps, NULLs, dates, CTEs — indexed by pattern with live practice links.
5-Month Analyst Roadmap
100 SQL reps, one messy portfolio project, an evidence-backed resume, 40 targeted applications: the complete 5-month analyst roadmap with milestones.
4 GROUP BY Traps, Wrong vs Right
WHERE vs HAVING, nullable grouping keys, bare SELECT columns: 4 GROUP BY traps that run without errors yet fail take-homes, each with the fix.
Power BI + GenAI Analyst Workflows
Insight briefs, GenAI QA loops, stakeholder self-serve pages: the 3 systems that get analysts promoted, with build steps and success metrics.
Nested Query to CTE in 4 Steps
Turn a 3-level nested subquery into a readable CTE interviewers can maintain at 2am: a 4-step refactor worksheet with before-and-after SQL code.
Data Courses Compared + Checklist
Udemy vs structured programs vs ISA vs free micro-courses with real pricing math, plus a 7-question placement-guarantee checklist every buyer needs.
5 SQL Date Patterns for Interviews
Month-over-month growth, rolling averages, cohorts, weekday splits, days-between events: the 5 SQL date patterns analyst JDs repeat, with queries.
Excel to SQL: Full Translation Map
VLOOKUP to JOIN, PivotTables to GROUP BY, filters to WHERE: every Excel skill mapped one-to-one to SQL, with a live practice path included inside.
RANK vs DENSE_RANK: Tie-Traps
Top-3-per-group with ties: ROW_NUMBER vs RANK vs DENSE_RANK explained side by side, plus 5 tie-trap drills with full answer keys for interviews.
Data Analyst Roadmap 2026: Complete Step-by-Step Guide to Land a Job
A complete, practitioner-backed Data Analyst roadmap for 2026. Master SQL, Excel, Power BI, Python, build high-impact portfolio projects, and navigate the job hunt to land a ₹5–10 LPA role.
Data Analyst Skills Roadmap (2026): What to Learn First
The modern 2026 data analyst skills roadmap. Learn the optimal order to master SQL, Excel, Python, and Tableau with free courses and real-world projects.
Data Analyst Vs Engineer Vs Data Scientist
Compare data analyst, data engineer, and data scientist roles. Explore career paths, salaries, skills, and how to become a top data scientist in 2026.
SQL Date Functions Guide: Practical Examples (2026)
Master sql date functions with practical examples. Learn DATE_TRUNC, EXTRACT, interval rolling windows, and how to avoid the timestamp BETWEEN trap.
Window Functions in SQL: Practical Guide & Examples
Master window functions in sql with practical examples. Learn OVER, PARTITION BY, running totals, rankings, and lead lag calculations step by step.
How to Use Leetcode Alternatives: Complete Guide & Examples
Master how to use LeetCode alternatives to solve real-world SQL and Python problems. Explore hands-on platforms, code walkthroughs, and error fixes.
SQL Interview Questions for Experienced (2026 Guide)
Ace sql interview questions for experienced data analysts. Master window functions, query optimization, join fan-out, and scenario CTEs with code.
Understanding Null Semantics In Sql: 2026 Guide & Examples
Master three-valued logic and traps by understanding null semantics in sql. Learn NOT IN pitfalls, WHERE vs HAVING filtering, and safe COALESCE math.
Full Outer Join In Sql: 2026 Guide & Examples
Master the full outer join in sql with practical examples, billing reconciliation queries, syntax rules, and NULL handling for data analysts.
LEFT JOIN vs LEFT OUTER JOIN in SQL: Key Differences
Is there any difference between LEFT JOIN and LEFT OUTER JOIN in SQL? Learn ANSI syntax rules, performance benchmarks, and common WHERE clause traps.
Data Analyst Interview Questions 2026: Complete Preparation Guide
30+ real data analyst interview questions with schemas, solutions & pitfalls — SQL OAs vs live technical rounds, Python, modern data stack, product cases & behavioral.
Excel Practice Online: 15 Business Exercises & Solutions
Practice Excel formulas online with 15 real business exercises. Master XLOOKUP, INDEX MATCH, dynamic arrays, pivot tables, and financial modeling.
Free Excel Practice Sheets & Datasets: 10 Real Workbooks
Download 10 free Excel practice sheets and datasets for data analytics. Practice VLOOKUP, XLOOKUP, pivot tables, SUMIFS, and real business dashboards.
Python Practice Questions: 25 Real Problems & Solutions
Practice 25 real Python problems for data analytics. Solve exercises on data types, control flow, functions, lambdas, file I/O, error handling, and pandas.
Python Programs for Practice: 20 Real Analytics Scripts
Practice 20 real Python programs for data analytics. Master data cleaning, list comprehensions, dictionary aggregations, loops, and pandas DataFrames.
Data Analyst Salary Guide 2026: US & India in INR (₹5L–₹1.2 Cr)
Compare 2026 Data Analyst salaries in INR: US ($86K ≈ ₹72L), Canada (C$85K ≈ ₹53L), and India (₹5L–₹35L+). See verified 0–5 yr experience bands and GCC pay.
SQL Interview Questions for Data Analyst (2026 Guide)
Master 2026 SQL interview questions for data analysts. Real queries, window functions, joins, common traps, and runnable code solutions.
SQL Joins Practice Exercises: 15 Real Queries & Answers
Master SQL joins with 15 real business practice exercises. Solve INNER, LEFT, RIGHT, FULL OUTER, CROSS, and SELF JOINs with schemas and expected outputs.
SQL Practice Questions: 25 Real Business Queries & Answers
Practice 25 real-world SQL queries with solutions, schema diagrams, and expected outputs. Master joins, window functions, and aggregations for interviews.
ROW_NUMBER vs RANK vs DENSE_RANK in SQL (Tie Examples)
Understand the exact difference between ROW_NUMBER(), RANK(), and DENSE_RANK() in SQL. See how ties are handled (1,2,3 vs 1,2,2,4 vs 1,2,2,3) with interactive queries.
Tableau Interview Questions: 25 Senior Scenarios & Answers
Prepare for Tableau interviews with 25 real scenario questions and answers. Master LOD expressions, table calcs, extract optimization, and data modeling.
Sort & Filter in Excel Without Mixing Data (Fix Rows Fast)
Prevent misaligned rows when sorting or filtering in Excel. Fix auto-filters stopping at blank rows and learn why Ctrl+T permanently stops data scrambling.
SQL CTE Guide: WITH Clause Syntax, Chaining & Examples
Master SQL CTEs (Common Table Expressions). Learn WITH clause syntax, how to chain multiple CTEs, build recursive queries, and practice in our live sandbox.
30 SQL Interview Questions for Freshers & Analysts (2026)
Master top 30 SQL interview questions for freshers and analysts. Includes verified SQL queries for JOINs, Window Functions, CTEs, and GROUP BY.
SQL JOIN Fan-Out: How to Fix Duplicate Rows & Broken SUM
Fix duplicate rows and inflated SUM/AVG totals in SQL joins. Learn what causes join fan-out, how to pre-aggregate data, and solve classic interview traps.
UNION vs UNION ALL in SQL: Key Differences
Learn the difference between UNION and UNION ALL in SQL, why UNION ALL is faster, when deduplication matters, and how to avoid costly sorting overhead.
Basic Excel Formulas: The Top 10 Formulas Every Analyst Needs to Know
Learn essential basic excel formulas: master SUM, AVERAGE, COUNT, IF, VLOOKUP, and conditional functions with syntax, examples, and practical fixes.
The 8 Best Data Science Books You Must Read in 2026
Discover the best data science books for statistics, machine learning, Python coding, data architecture, and executive storytelling with reviews.
Top 20 Business Analyst Interview Questions and Answers (2026 Guide)
Master top business analyst interview questions: BRD vs FRD, Agile user stories, MoSCoW prioritization, stakeholder management, and case scenarios.
CAGR Formula in Excel: Growth Rate with RRI and Power Method
CAGR formula Excel guide: compute annualised growth with =(End/Start)^(1/n)-1 and =RRI(). Investor examples, negative bases, and CAGR vs XIRR explained.
How to Compare Two Columns in Excel: 5 Methods (with Formulas)
How to compare two columns in Excel: equality checks, IF flags, COUNTIF matching, conditional formatting highlights, and VLOOKUP reconciliation steps.
Compound Interest Formula in Excel: FV, Growth, and SIP Examples
Compound interest formula Excel guide: grow savings faster with =FV(rate, nper, pmt), the power-operator method, SIP math, and yearly compounding examples.
CREATE TABLE in MySQL: Syntax, Data Types & Constraints Guide
Master CREATE TABLE in MySQL with syntax examples, primary keys, foreign keys, AUTO_INCREMENT, constraints, and InnoDB engine best practices.
Data Analyst Boot Camp: Are They Worth It in 2026? (Honest Review)
Is a data analyst boot camp worth the $15,000+ tuition? Review hidden costs, placement rates, curricula, and how to build a free self-directed alternative.
Top Data Analyst Projects for Your Portfolio to Get Hired (2026)
Discover top data analyst projects that stand out to hiring managers. Real-world business cases, public datasets, SQL/Python code, and portfolio tips.
Data Analyst Portfolio Guide (2026): 3 Projects That Get You Hired | Topfolio
Learn how to make a data analyst portfolio in 2026. The proven 3-project framework (SQL, Python EDA, Power BI), GitHub README templates & real business datasets.
Data Science in Finance: Top Use Cases, Algorithms & Career Guide
Explore data science in finance with real-world use cases in fraud detection, credit risk modeling, algorithmic trading, and quantitative analytics.
Top 20 Data Scientist Interview Questions and Answers (2026)
Master data scientist interview questions across machine learning, statistics, SQL, Python coding, and product case studies with detailed answers.
DDL SQL Commands: Complete Guide to Data Definition Language
Master DDL SQL commands: CREATE, ALTER, DROP, TRUNCATE, and RENAME with practical syntax, schema constraints, and DDL vs DML comparisons.
How to Delete Blank Rows in Excel: 4 Safe Methods (with Checks)
How to delete blank rows in Excel safely: Go To Special Blanks, AutoFilter blanks, helper COUNTBLANK flags, and backup checks every analyst must run first.
Delete Duplicate Records in SQL: 3 Proven Methods with Examples
Learn how to delete duplicate records in SQL using ROW_NUMBER() CTEs, self-joins with MIN/MAX IDs, and safe transaction workflows across dialects.
DML Commands in SQL: INSERT, UPDATE, DELETE, and MERGE (with Examples)
Master dml commands in sql: learn syntax for INSERT, UPDATE, DELETE, and MERGE, avoid catastrophic updates without WHERE, and compare DML vs DDL.
Top 20 Docker Interview Questions and Answers (2026 Guide)
Prepare for Docker interview questions covering containerization vs VMs, Dockerfile optimization, multi-stage builds, networking, and volumes.
Conditional Formatting in Excel: Highlight Rows & Rules
Master conditional formatting in Excel to highlight entire rows based on cell values or formulas. Learn =$A2 locks, SEARCH rules, and key analyst fixes.
Data Cleaning in Excel: How to Remove Blank Rows, Spaces & Duplicates
Master data cleaning in Excel: learn how to remove blank rows in excel, strip stray spaces with TRIM, fix casing, and delete duplicates safely.
Excel Formula List: The Top 30 Functions Every Analyst Uses (with Examples)
The complete excel formula list for data analysts: 30 essential functions across Lookups, Math, Logical, Text, and Date categories with syntax and examples.
Excel Formulas: The Complete Guide for Data Analysts (2026)
Master essential excel formulas in this complete guide: lookup, math, dynamic arrays, text, financial modeling, and 30+ core functions for analysts.
Excel Formulas Shortcut Keys: The 15 Must-Know Shortcuts for Analysts
Master excel formulas shortcut keys: AutoSum Alt + =, lock references with F4, audit with Ctrl + `, fill with Ctrl + D, and calculate 10x faster.
Excel Formula vs Function: Key Differences, Formula Bar & Syntax
Understand the difference between an excel formula and a function. Master MS Excel formulas syntax, formula bar auditing, and data cleaning workflows.
Pivot Table in Excel: The Step-by-Step Data Summarization Guide
Master how to create a pivot table in excel: step-by-step tutorial on Rows, Columns, Values, Filters, Calculated Fields, and fast data summarization.
VLOOKUP vs XLOOKUP in Excel: When to Use Each (with TRANSPOSE)
VLOOKUP vs XLOOKUP in Excel: compare the vlookup formula in excel against XLOOKUP, avoid column index bugs, and reshape dynamic array spills.
Top 20 FastAPI Interview Questions and Answers (2026 Guide)
Master top fastapi interview questions: async/await, Pydantic validation, Depends injection, ASGI vs WSGI, CORS, and deployment architectures.
FILTER Formula in Excel: Dynamic Filtered Lists (with Examples)
FILTER formula in Excel explained: =FILTER(array, include) builds live filtered lists. Multiple criteria, troubleshooting #CALC!, and analyst examples inside.
The Future of Data Science: Trends, AI Impact & Career Outlook (2026)
Explore the future of data science in the era of Generative AI. Discover emerging trends, evolving skill sets, salary outlooks, and career strategies.
Top 20 Gen AI Interview Questions and Answers (2026 Guide)
Master top gen ai interview questions: Transformers, self-attention, RAG pipelines, fine-tuning vs prompting, LoRA, RLHF, and hallucination fixes.
How to Hide Columns in Excel: Shortcuts, Grouping, and Best Use
How to hide columns in Excel: right-click Hide, Ctrl+0, grouping outlines for reports, and what hiding does to formulas, printing, and shared workbooks.
How to Combine Two Columns in Excel: Ampersand, TEXTJOIN, and Flash Fill
Learn how to combine two columns in excel using the ampersand (&), TEXTJOIN, CONCAT, and Flash Fill. Add spaces, format dates, and preserve data.
How to Freeze Rows in Excel: Top Row, Multiple Rows, and Panes
Learn how to freeze rows in excel: lock the top row, freeze multiple rows, lock rows and columns simultaneously, and use the Alt + W + F + F shortcut.
How to Remove Duplicates in Excel: Built-in Tools, UNIQUE, and Fixes
Learn how to remove duplicates in excel using the Data tab tool, UNIQUE formula, and Advanced Filter. Step-by-step methods, edge cases, and analyst fixes.
INDEX MATCH Function in Excel: Flexible Lookups (with Examples)
INDEX MATCH function in Excel explained: =INDEX(return, MATCH(lookup, range, 0)). Left lookups, two-way matches, and XLOOKUP migration tips for analysts.
How to Insert Checkbox in Excel: Developer Tab + COUNTIF Uses
How to insert checkbox in Excel: enable Developer tab, link cells to TRUE/FALSE, count checked boxes, and build interactive task trackers step by step.
Top 20 Kubernetes Interview Questions and Answers (2026 Guide)
Master Kubernetes interview questions covering control plane architecture, pod lifecycles, services, Ingress, troubleshooting, and K8s security.
Top 20 Machine Learning Interview Questions and Answers (2026 Guide)
Master the top 20 machine learning interview questions: bias-variance tradeoff, regularization, ROC-AUC, XGBoost, and production model evaluation.
How to Merge Two Cells in Excel: Merge vs CONCAT vs TEXTJOIN
How to merge two cells in Excel: Merge & Center, the & operator, CONCAT and TEXTJOIN. Keep values safe, fix sorting issues, and choose the right method.
Normalization in SQL: 1NF, 2NF, 3NF & BCNF Explained with Examples
Learn normalization in sql with step-by-step table examples from unnormalized data to 1NF, 2NF, 3NF, and BCNF to eliminate data anomalies.
OFFSET in SQL: Syntax, Pagination & Performance Optimization
Master OFFSET in SQL for database pagination. Learn LIMIT/OFFSET syntax across dialects, deep pagination performance pitfalls, and keyset seek methods.
Order of Execution in SQL: The 8 Stages Every Analyst Must Understand
Master the order of execution in sql: learn how databases process FROM, WHERE, GROUP BY, HAVING, and SELECT clauses, and resolve query alias errors.
Top 20 Pandas Interview Questions and Coding Answers (2026 Guide)
Master Pandas interview questions with practical DataFrame coding solutions, loc vs iloc, groupby aggregations, merging, and memory optimization.
Percentage Formula in Excel: Growth, Totals, and Changes (with Examples)
Master the percentage formula in excel: calculate percentage of total, percentage change, markup, and discounts with practical formulas and error fixes.
PMT Formula in Excel: Calculate Loan EMIs and Payments (Examples)
PMT formula in Excel explained: compute EMIs with =PMT(rate, nper, pv). Loan examples, rate conversions, total-interest math, and analyst mistakes to avoid.
Top 20 Python Basic Interview Questions and Answers (2026 Guide)
Master the top 20 python basic interview questions: list vs tuple, mutable vs immutable, decorators, generators, and core coding questions with answers.
Python for Data Analysis: The Complete Workflow Playbook (2026)
Master python data analysis with this complete playbook: pandas wrangling, exploratory data analysis, statistical cohorts, and production data pipelines.
Python Tutorial: The Complete Guide for Data Analysts (2026)
Master Python programming with this comprehensive python tutorial for data analysts: variables, data structures, control flow, functions, NumPy, Pandas, and real-world projects.
RANK Formula in Excel: Rank Sales, Scores, and KPIs (with Examples)
Rank formula in Excel explained: use RANK, RANK.EQ, and RANK.AVG to rank sales, scores, and KPIs. Syntax, examples, ties, and fixes analysts need daily.
Top 20 REST API Interview Questions and Answers (2026 Guide)
Master the top 20 rest api interview questions: idempotency, PUT vs PATCH, status codes, JWT authentication, rate limiting, and REST vs GraphQL.
SEQUENCE Formula in Excel: Auto-Numbering and Date Series (Guide)
SEQUENCE formula in Excel explained: =SEQUENCE(rows, columns, start, step) for IDs, date series, and dynamic grids. Spill fixes and analyst examples included.
Set Operators in SQL: UNION, UNION ALL, INTERSECT & EXCEPT Guide
Master set operators in SQL with practical examples of UNION, UNION ALL, INTERSECT, and EXCEPT/MINUS to combine query result sets effectively.
Case Statement in SQL: Complete Guide to CASE WHEN & Conditional Aggregation
Master the case statement in sql: use CASE WHEN and SUM(CASE WHEN ...) to pivot data, categorize distributions, and aggregate conditionally in a single scan.
SQL Cheat Sheet: Commands, Queries, and Window Functions Reference
Bookmark this comprehensive sql cheat sheet: essential syntax for SELECT, JOINs, aggregations, Window Functions, CTEs, and query order of execution.
SQL COUNT Function: COUNT(*), COUNT(1) & COUNT(DISTINCT) Guide
Master the SQL COUNT function with examples of COUNT(*), COUNT(1), COUNT(DISTINCT), NULL handling, and conditional counting techniques.
SQL for Data Analyst: Complete Guide, Key Skills & Queries
Master SQL for data analyst roles with real-world query patterns, window functions, aggregations, cohort analysis, and practical workflows.
SQL Performance Tuning: 7 Proven Strategies to Accelerate Slow Queries
Master SQL performance tuning with execution plan analysis (EXPLAIN ANALYZE), indexing best practices, sargable queries, and join optimizations.
SQL Projects for All Levels: Beginner to Advanced Portfolio Guide
Stand out to hiring managers with these 6 real-world SQL projects for beginner, intermediate, and advanced data analysts with datasets and code.
SQL RANK Function: RANK vs DENSE_RANK vs ROW_NUMBER Guide
Master the SQL RANK function with side-by-side comparisons of RANK, DENSE_RANK, and ROW_NUMBER, PARTITION BY logic, and Top-N group queries.
Subquery in SQL: Single-Row, Correlated, and Nested Queries (with Examples)
Master subquery in sql: understand nested queries across SELECT, FROM, and WHERE clauses, correlated vs non-correlated subqueries, and performance fixes.
SUBTOTAL Formula in Excel: Subtotals That Respect Filters (Guide)
SUBTOTAL formula in Excel explained: function numbers 1–11 vs 101–111, filtered totals that stay correct, and step-by-step analyst examples with fixes.
SUM Formula in Excel: AutoSum, Ranges, and 3D Sheet Sums (with Examples)
Master the sum formula in excel: learn syntax, AutoSum shortcut Alt + =, multi-range additions, 3D sheet sums, and troubleshooting silent errors.
Tableau Complete Guide: Master Business Intelligence and Dashboards (2026)
Master Tableau for business intelligence: data connections, visual analytics, calculated fields, LOD expressions, table calculations, and interactive dashboards.
Transpose Excel: How to Switch Rows and Columns (Formula & Shortcut)
Learn how to transpose excel data: switch rows to columns using Paste Special Transpose, the dynamic =TRANSPOSE() formula, and Power Query.
How to Unhide Columns in Excel: 5 Methods (with Shortcuts)
How to unhide columns in Excel: drag headers, right-click Unhide, Ctrl+Shift+0, Go To Special, and fixes for columns that refuse to reappear. Full guide.
VLOOKUP Formula in Excel: Syntax, Step-by-Step Guide, and Common Fixes
Master the vlookup formula in excel: understand all 4 arguments, build exact lookups, fix #N/A errors, and compare with XLOOKUP and INDEX MATCH.
What Is SQL? The Complete Beginner to Pro Database Guide (2026)
What is SQL? Learn how Structured Query Language works, relational database concepts, SELECT queries, JOINs, DDL vs DML commands, and analyst workflows.
XLOOKUP Formula in Excel: Syntax, Examples, and VLOOKUP Migration
XLOOKUP formula in Excel explained: syntax, exact match, reverse lookup, and if_not_found. Real examples plus VLOOKUP migration tips for analysts daily.
We Made All Learning Free. Here's Why — and What We Ask in Return: Feedback.
Every Topfolio micro-course video, lesson, quiz and practice sandbox is now 100% free. The only paid layer is the optional ₹99 verified certificate + AI review. Try it and tell us what to fix.
Amazon Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Amazon data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Flipkart Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Flipkart data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Google Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Google data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
JPMorgan Chase Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to JPMorgan Chase data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Razorpay Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Razorpay data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Swiggy Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Swiggy data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Uber Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Uber data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Walmart Global Tech Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Walmart Global Tech data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Zepto Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Zepto data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Zomato Data Analyst Interview Questions 2026: SQL, Cases & Solutions
Comprehensive 2026 guide to Zomato data analyst and analytics interviews. Round breakdowns, live SQL problem scenarios with code solutions, and compensation bands.
Data Analyst vs DE vs DS Salary in India (2026): ₹5L to ₹1.6 Cr | Topfolio
Verified 2026 salary progression for Data Analysts, Data Engineers & Scientists in India (0–6+ yrs). Fixed base, bonus & RSUs across IT, GCC & FAANG+ bands.
Connect VS Code to PostgreSQL with SQLTools (Step-by-Step)
Connect Visual Studio Code to PostgreSQL using SQLTools in 4 steps: install drivers, configure host/port credentials, fix search_path errors, and run queries.
A/B Testing in Python: Sample Size, Hypothesis Testing & P-Value Analysis
Complete A/B testing guide for data analysts in Python. Calculate sample sizes with statsmodels, detect Sample Ratio Mismatch (SRM), run proportion z-tests and Welch's t-tests, and avoid the peeking problem.
Customer Analytics in Python: Cohort Analysis, RFM Segmentation & LTV
Master customer analytics in Python with Pandas and Seaborn. Calculate RFM scores, build customer segments, run monthly cohort retention heatmaps, and estimate Customer Lifetime Value (LTV).
Data Analyst Resume Guide: How to Stand Out in 2026
Write a data analyst resume that gets callbacks. The exact formula, section-by-section breakdown, common mistakes, and how to stand out with no experience.
Relative vs Absolute Cell References in Excel (What $ Does)
Learn the difference between relative and absolute cell references in Excel. Discover what the dollar sign ($) does, when to press F4, and how to stop autofill drift.
Excel Charts for Analysts: Pick the Right Visual and Use Aggregation Intentionally
Choose the right Excel chart for the message. Learn column, line, pie, and combo visuals — and how Excel aggregates values before plotting.
Excel for Data Analysts: Interface Tour in 6 Minutes
New to Excel for analytics? Tour the ribbon, grid, formula bar, and file basics that prevent silent errors — and find the right tab in seconds.
Best Free Datasets for Data Analyst Practice
Curated list of free datasets perfect for building your portfolio. From beginner-friendly to advanced real-world data.
Market Basket Analysis in Python: Support, Confidence, Lift & Apriori Explained
Master Market Basket Analysis and Association Rule Mining in Python. Learn the mathematical intuition behind Support, Confidence, and Lift, one-hot encode transaction baskets, and implement Apriori and FP-Growth using Pandas and Mlxtend.
REST APIs for Data Analysts in Python: Authentication, Pagination & JSON Normalization
Master REST API data extraction in Python. Learn how to handle Bearer tokens and API keys, loop through offset and cursor pagination, flatten nested JSON with pd.json_normalize(), and build fault-tolerant pipelines with automatic retries.
Python Exploratory Data Analysis (EDA): The Complete Step-by-Step Workflow
Master the complete 6-stage Python Exploratory Data Analysis (EDA) framework. Learn structured data inspection, missing value imputation, IQR outlier detection, distribution analysis, correlation heatmaps, and feature profiling.
Python Pandas for Data Analysis: Getting Started Guide (2026)
Learn Python Pandas for data analysis from scratch. DataFrames, filtering, groupby, merging, data cleaning, and 5 one-liners every data analyst should know.
Product Analytics in Python: Funnel Conversion, Drop-off & User Journey Mapping
Master product funnel analysis in Python with Pandas and Plotly. Calculate step-by-step conversion rates, drop-off percentages, time-to-convert distributions, and interactive Sankey user journeys.
WHERE vs HAVING in SQL: Execution Order & Key Differences
Master WHERE vs HAVING in SQL. Learn why WHERE filters before GROUP BY, why aggregate functions fail in WHERE, and the full 7-step query execution order.
SQL Subqueries Explained: Scalar, Correlated & Syntax Guide
Master the 3 types of SQL subqueries: scalar, multi-row (IN/EXISTS), and correlated. Avoid the NOT IN NULL trap and learn when to refactor to readable CTEs.
SQL vs NoSQL: Complete Guide for Data Analysts
Understand the differences between SQL and NoSQL databases. Learn when to use each and which to learn first.
Time Series Analysis & Forecasting in Python: Trend, Seasonality & Moving Averages
Complete guide to time series analysis and forecasting in Python. Master datetime indexing, resampling, moving average smoothing, seasonal decomposition, and the Augmented Dickey-Fuller (ADF) stationarity test.
Welcome to the Topfolio Blog
Introducing the Topfolio blog — your go-to source for data analytics tutorials, career guides, interview prep, and student success stories.
A/B Testing in Python: From Sample Size to p-Value Without the Ritual
Run A/B tests in Python the right way — simulate control vs variant, check SRM, run chi-square and t-tests, and read p-values correctly.
API Masterclass in Python: Authentication, Pagination, and JSON to DataFrame
Call any REST API from Python — handle API keys, Basic Auth, query params, pagination, and flatten nested JSON into Pandas DataFrames.
Applied ML Cheatsheet in Python: Iris Dataset From EDA to Cross-Validation
End-to-end ML in Python on the Iris dataset — EDA, train-test split, scaling, logistic regression, decision trees, and metrics.
Customer Analytics in Python: Cohort, RFM, and the First Query That Matters
Run RFM segmentation and cohort retention in Python — recency, frequency, monetary scores and a retention heatmap from transaction logs.
Python Database Connectivity: SQLite to BigQuery Without Hardcoding Passwords
Connect Python to SQLite, PostgreSQL, MySQL, Snowflake and BigQuery with SQLAlchemy and pandas read_sql — securely via .env files.
EDA in Python: A Checklist That Catches Silent Data Errors
A step-by-step EDA checklist in Python — data loading, missing values, outliers, and feature engineering — with a downloadable Jupyter notebook.
Excel Pivot Table Dashboard with Slicers: 10-Minute Tutorial
Build an interactive Excel pivot table dashboard in 10 minutes. Learn how to summarize data, connect Slicers across multiple PivotTables, and add PivotCharts.
Python Lists and Dictionaries: 10 Assignments With Answers in Python
Master Python lists and dicts — creating, slicing, appending, merging, and iterating — with 10 graded assignments and solutions.
Market Basket Analysis in Python: Support, Confidence, and What to Do With Them
Build a market basket analysis in Python — basket matrix, co-occurrence, lift scores, and a rule-based recommender from transaction logs.
NumPy Foundations: 30 Questions That Build Array Intuition
Learn NumPy from zero — arrays vs lists, zeros, arange, reshape, broadcasting, and vectorised operations with 30 hands-on questions.
Pandas Advanced Masterclass: Merge, Rank, and Window Functions Like SQL
Advanced Pandas — set_index, merge joins, rank vs dense_rank, shift/lead-lag, and groupby window functions mirroring SQL.
Pandas Cheatsheet: The 7 Sections Every Analyst Memorises
The Pandas cheatsheet analysts actually use — inspect, select, filter, handle nulls, sort, groupby, and merge with one-liner patterns.
Pandas Fundamentals: 40 Questions to Go From List to DataFrame
Pandas fundamentals in 40 questions — Series, DataFrame, head, dtypes, loc vs iloc, filtering, sorting, and null handling.
Pandas Master Workbook: 50 GroupBy, Aggregate, and Merge Drills
50 Pandas drills on groupby, agg, pivot tables, and merges — the repetition that makes aggregation second nature.
Product Funnel Analysis: Where Users Drop and How to Prove It in Python
Track users from landing page to purchase in Python — build a funnel, calculate step conversion, and visualise drop-off with Plotly.
Python Basics Workbook: Control Flow and Functions With 20 Drills
Master Python basics — if/elif/else, for/while loops, functions, and return values — with 20 bite-size drills and solutions.
Python Fundamentals Master: Strings, Regex, and Data Structures in 30 Questions
Complete Python fundamentals — slicing, f-strings, regex, lists, dicts, and file handling — 30 questions with explained solutions.
Python String Assignments: 5 Real-World Slicing and Formatting Drills
Practice Python strings on real tasks — email slicer, reverser, cleaner, vowel counter, and f-string formatter with solutions.
Tableau Calculated Fields Tutorial: How to Create & Syntax
Learn how to create calculated fields in Tableau. Master row-level vs aggregate formulas, avoid 'cannot mix aggregate' errors, and use IF/THEN functions.
Tableau Charts for Analysts: Bars, Lines and Scatter Plots That Answer Questions
Choose Tableau charts that answer questions: bars for categories, lines for time and scatters for correlation and outliers.
Tableau Connecting Data Sources: Live vs Extract for Analysts
Connect CSV, Excel and databases in Tableau via the Connections pane and choose Live vs Hyper Extract with data source filters.
Tableau Dashboard Layout Guide: Containers, Tiled & Design
Master Tableau dashboard layout: configure Horizontal & Vertical tiled containers, manage Item Hierarchy, set padding, and choose between Stories vs Dashboards.
Dimensions vs Measures in Tableau: Blue vs Green Pills Guide
Understand Dimensions vs Measures and Discrete vs Continuous in Tableau. Learn why blue pills create headers, green pills create axes, and how to convert them.
Tableau Marks Card Guide: Color, Size, Label & Visual Sorts
Master the Tableau Marks Card: encode data with Color, Size, Label, and Tooltip. Learn how to sort marks, control gradients, and format clean visual charts.
Tableau Scatter Plots: Correlation and Outliers for Analysts
Build Tableau scatter plots for correlation and outliers: map Sales vs Profit, add Detail, Size, Color and fix overplotting.
Tableau LOD Expressions Guide: FIXED, INCLUDE & EXCLUDE
Master Tableau Level of Detail (LOD) expressions. Learn syntax and examples for FIXED, INCLUDE, and EXCLUDE to calculate Percent of Total without filter errors.
Tableau Parameters: Dynamic Filters and Top-N Without Rewriting Formulas
Create Tableau Parameters for dynamic threshold and Top-N RANK filters without rewriting formulas. Slider and list controls.
Tableau Performance and Extracts: Speed Up Dashboards
Speed up Tableau with Hyper extracts and data source filters: choose Extract vs Live and schedule refresh cadence.
Tableau Relationships vs Joins: Which Should You Use & Why?
Compare Tableau Relationships vs Physical Joins. Learn how the logical layer (noodles) stops duplicated rows and inflated sums, and when to use classic joins.
Tableau Story vs Dashboard: What is a Story & How to Use It
Tableau Story vs Dashboard explained: learn what a Story is, how to assemble story points with live-linked dashboards, and when to use presentations (F7).
Tableau Table Calculations: Running Total, Difference and Moving Average
Use Tableau Quick Table Calculations: Running Total, Difference and 14-day Moving Average with continuous dates.
Tableau Tips for Analyst Workflows: URL Actions and Interactivity
Add URL Actions to Tableau dashboards: static vs dynamic links with field injection and browser testing workflow.
Time Series for Analysts: Trend, Seasonality, and the 7-Line Forecast
Decompose trend and seasonality, resample daily to monthly, smooth with rolling windows, and build a naive forecast in Python.
Build AI Agents with LangGraph: From State to Tool-Calling Graph
Build autonomous AI agents with LangGraph and Gemini — state, nodes, edges, tool integration, and a compiled graph you can run locally.
Text Mining for Analysts: TF-IDF Without the Jargon
Turn customer reviews into insights — clean text, score sentiment with TextBlob, and surface complaints with word frequencies in Python.