I have found CSVFiddle.io a great place to practice my SQL programming.

Examples:
2022 London Marathon Runners - Analysing the finish table of the 2022 London Marathon.

Wages, Departments and Salary - Practice analysing a small dataset of employees, department and salary

World Population Data - Analysing the population of countries over the years.

BA Reviews - Analysing reviews from British Airways passengers

US States Climate Change - Analysing average yearly temperatures of US States over the years.

Consecutive Employee Work Days - I saw this task on the Medium blog… ordering employees by most consecutive days worked.

Misc:
A link to my LeetCode portfolio - where I’m currently working through Leetcode 50.