获取具有值的列的百分比

Question

I tried to do this:

 SELECT (SELECT COUNT(*)
 FROM users WHERE email != '') / (SELECT COUNT(*) FROM users)

But it gave me this error in php Operand should contain 1 column(s), in mysql everything works. Any other solution?

EDIT : its not exactly like that I had also groups by months, the above query works but the accepted answer solves my error

Answer 1

You can do it in a single query:

SELECT SUM(email != '') / COUNT(*) 
    AS ratio
  FROM users

... or, if you need percentage:

SELECT 100 * SUM(email != '') / COUNT(*)
    AS percentage
  FROM users