Master SQL analytics without collapsing rows.
Develop a precise mental model for OVER, PARTITION BY, ORDER BY, ranking, LAG and LEAD, frames, dialect differences, and performance.
What you will leave with
You can design and debug production-style window queries, including top-N per group, running totals, period comparisons, and session logic.
What you will be able to do
The curriculum is organized around these 4 practical outcomes.
Explain what each part of OVER changes
Choose the correct ranking function when ties matter
Build running, rolling, and period-comparison metrics
Control frames and translate patterns across SQL dialects
Course map
Curriculum
Open a module to inspect every section before you start. Your progress follows you through the course.
Why window functions exist, The OVER() clause anatomy, PARTITION BY, slicing the data, and more.
ROW_NUMBER, unique sequential ranks, RANK, competition ranks with gaps, DENSE_RANK, tiers without gaps, and more.
SUM/AVG/COUNT/MIN/MAX with OVER, Running totals, Grand totals & percent-of-total, and more.
LAG, look at the previous row, LEAD, look at the next row, Period-over-period growth, and more.
Default frames, and why they bite, ROWS, physical row counting, RANGE, logical value counting, and more.
The SQL standard vs vendor reality, PostgreSQL extensions: FILTER, IGNORE NULLS, RANGE BETWEEN INTERVAL, only in some dialects, and more.
FIRST_VALUE & LAST_VALUE, and the LAST_VALUE trap, NTH_VALUE, sampling the Nth row, PERCENT_RANK & CUME_DIST, and more.
Windows vs self-joins, when each wins, Common anti-patterns and how to spot them, EXPLAIN reading for window queries, and more.
Who this course is for
Start with the background you have. The prerequisite notes above tell you exactly what is assumed.
Analysts moving into advanced SQL
Analytics engineers
Candidates preparing for senior SQL interviews
Continue learning
Each course stands on its own. Pick the one closest to the next task you need to handle.
Turn complex business logic into readable SQL.
Design experiments that survive real scrutiny.
Write useful SQL from your first lesson.
Start the course
Module 1 introduces the language and example used throughout the rest of the course.
