Frequency Table by user in SQL

Question

Very basic SQL question (DB is MySQL):

I want a table of number of transactions by users.

User ID   Transaction count
1         43
2         213
3         0
4         23
5         0

In a table I have the two relevant records (user_id and buy_count).

How could I get the table I want?

Thanks,

Roberto

Answer 1

Group By

SELECT user_id, SUM(buy_count)
FROM table
GROUP BY user_id