How to find relative relation in rows in mysql

Question

I am new to MySQL query, so please help me solve this problem, thanks!

I have a table:

query url num_clicks
-------------------------
qa ua 20
qa ub 30
qa uc 50
qb ud 10
qb ue 90

I would like to calculate the relative ratio for the same query, for example:

query url num_clicks ratio
--------------------------------
qa ua 20 0.2
qa ub 30 0.3
qa uc 50 0.5
qb ud 10 0.1
qb ue 90 0.9

How to do this using a single query? Thank!

Answer 1

SELECT query,url,num_clicks,num_clicks/t.totalclicks AS ratio
FROM MyTable
INNER JOIN (
   SELECT
   query,SUM(num_clicks) AS totalclicks
   GROUP BY query
) AS t ON MyTable.query = t.query