Question

This has probably been asked before, but I’m unable to make my way through the myriad of search results.

Given a non-normalized MySQL table, what is the most optimized query to count the number of times each distinct value of column x was used?

e.g. Given a table containing

mike
mary
mike

Return results like:

mike 2
mary 1

From the MySQL documentation, it would seem that count is an aggregate function that can be used with GROUP BY, but it’s not doing what I want (it’s returning the total number of rows in the GROUP BY, not the number of appearances for each row. i.e. this does not work SELECT count(email) as c FROM orders GROUP BY email

Answer 1

select email, count(*) as c FROM orders GROUP BY email