SQL

Rows, results, joins and metrics before changing data, on PostgreSQL 18.

63 lessons · 5 projects · open now

Four steps, one path

Each step includes everything before it, and your progress carries over. Start free; choose what the later steps are worth to you.

1. 1Free

   Introduction

   Run and explain your first PostgreSQL query in the browser. 4 cumulative lessons.

   • Run and explain your first PostgreSQL query in the browser.
   • Verify results on ordinary, missing-value and boundary data.
   Start for free
2. 2Pay what you want

   Foundations

   Rows, NULL, joins and correct metrics; a read-only library report. 28 cumulative lessons.

   • Rows, NULL, joins and correct metrics; a read-only library report.
   • Verify results on ordinary, missing-value and boundary data.
   See this step
3. 3Pay what you want

   Complete Course

   Schema, constraints, transactions and a reproducible equipment-lending database. 52 cumulative lessons.

   • Schema, constraints, transactions and a reproducible equipment-lending database.
   • Verify results on ordinary, missing-value and boundary data.
   See this step
4. 4Pay what you want

   Extended Practice

   Window analytics, query maintenance and safe recursive hierarchy traversal. 63 cumulative lessons.

   • Window analytics, query maintenance and safe recursive hierarchy traversal.
   • Verify results on ordinary, missing-value and boundary data.
   See this step