Data & Analytics
14 posts in this category
Automating Data Quality Checks: SQL Templates for NULL, Duplicates, and Consistency
SQL checklist to catch data quality issues early. NULL checks, duplicates, referential integrity, range validation.
Anomaly Detection in SQL: Finding Outliers with Z-Score and IQR
Automatically detect abnormal data with SQL. Implement Z-Score, IQR, and percentile-based outlier detection.
Time Series Analysis in SQL: Mastering Moving Averages, YoY, and MoM Trends
Can't see the revenue trend? How to implement moving averages, YoY, and MoM comparisons in SQL.
A/B Test Analysis in SQL: Calculating Statistical Significance Yourself
Analyze A/B test results with SQL alone. Z-test, confidence intervals, and sample size calculation.
Advanced Funnel Analysis: Finding Conversion Rates and Drop-off Points in SQL
Pinpoint exactly where users drop off with SQL. Everything about calculating step-by-step conversion rates.
Building Cohort Analysis in SQL: The Complete Guide to Retention
Build cohort analysis without GA4. Implement monthly retention and N-day retention directly in SQL.
Mastering CTE: Escape Subquery Hell Once and For All
One WITH clause transforms unreadable queries into clear, logical steps. Recursive CTEs handle hierarchies with ease.
Build Your Own Marketing Funnel Without GA4 — Sessions, Attribution, ROAS in SQL
Learn how to implement sessions, attribution, funnels, and ROAS with pure SQL — no expensive analytics tools needed.
"We Need Python for This" — Handling Pivot, JSON, UTM, RFM All in SQL
Learn practical patterns to handle Pivot, JSON parsing, UTM extraction, and RFM segmentation with a single SQL query instead of 100 lines of Python.
BPE vs Byte-level Tokenization: Why LLMs Struggle with Counting
Why do LLMs fail at counting letters in "strawberry"? The answer lies in tokenization. Learn how BPE creates variable granularity that hides character structure from models.
The Real Bottleneck in RAG Systems: It's Not the Vector DB, It's Your 1:N Relationships
Many teams try to solve RAG accuracy problems by tuning their vector database. But the real bottleneck is chunking that ignores the relational structure of source data.
"Can SQL Do This?" — Escaping Subquery Hell with Window Functions
LAG, LEAD, RANK for month-over-month, rankings, and running totals
One Wrong JOIN and Your Revenue Doubles — The Complete Guide to Accurate Revenue Aggregation
Row Explosion in 1:N JOINs and how to aggregate revenue correctly
Why Does Your SQL Query Take 10 Minutes? — From EXPLAIN QUERY PLAN to Index Design
EXPLAIN, indexes, WHERE vs HAVING — diagnose and optimize slow queries yourself