Tutorial
Hands-on walkthroughs for SQL, Python, Excel and visualisation tools — every example is runnable, not a screenshot.
121 articles in Tutorial · Page 3 of 14
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.
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.
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.
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.
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.
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.