Guided path · 12 steps

SQL & Databases

Twelve steps through the entire SQL practice bank in difficulty order — joins, NULL handling and set operations first, then aggregates and HAVING, with the indexing/performance guide slotted in right before the two hardest problems (window functions, a correlated subquery) so the "why" lands before the hardest "how".

12 steps

Read
SQL Fundamentals: Joins, NULL, Aggregate Functions, and Subqueries
Run · Easy
Select Every Sales Employee
Run · Easy
Employee Count Per Department
Run · Easy
Employees With No Salary
Run · Easy
Union Employee and Department Names
Run · Medium
Average Salary Per Department
Run · Medium
Departments With More Than One Employee
Run · Medium
Employees Above Company Average
Run · Medium
Department With Highest Average Salary
Read
Understanding SQL Indexes and Query Performance
Run · Medium
Rank Employees By Department Salary
Run · Hard
Employees Above Their Own Department's Average