The Journal
Practical SQL, Python, data science and AI guides, written from real practice — not just to rank.
Python Strings: Methods and Slicing Explained
Python strings explained: indexing, slicing, split, join, strip, replace and f-strings, with real code and output, common mistakes…
Python Data Types Explained With Examples
Python data types explained simply: int, float, str, bool, list, tuple, set and dict, with real code and…
How to Learn Python: A Step-by-Step Roadmap
How to learn Python step by step: a seven-stage roadmap from variables to classes, files and errors, with…
SQL vs Excel for Data Analysis: When to Use Which
SQL vs Excel: what each is best at, a side-by-side comparison, the same task done both ways, and…
SQL Subquery vs CTE: Differences and When to Use
Subquery or CTE? Learn what each is, how they differ and when to use which in SQL, with…
NULL in SQL: IS NULL, COALESCE and Common Mistakes
What is NULL in SQL? Learn IS NULL, COALESCE and how NULL affects COUNT, AVG and NOT IN,…
SQL Window Functions Explained With Examples
SQL window functions explained simply: OVER, PARTITION BY, ROW_NUMBER, RANK, LAG and running totals, with sample tables and…
SQL WHERE vs HAVING: Difference With Examples
WHERE filters rows before grouping, HAVING filters groups after it. Learn the difference between WHERE and HAVING in…
How to Prepare for a SQL Interview: A Plan
How to prepare for a SQL interview: what rounds test, a topic checklist, a practice loop with timed…