How do I calculate ratios in SQL?

Question

Suppose I have a GAME table with the following fields

user_id, result

I wish to calculate win percentage defined as total numb

Answer 1

In MySQL, you can use this shortcut:

SELECT user_id, avg(Result = 'Win') AS WinPercent
FROM Game
GROUP BY user_id
ORDER BY WinPercent DESC

Assuming Result is never NULL (empty string is ok). Otherwise you have to use Result IS NOT NULL AND Result = 'Win'