mySQL cross referencing

[blacktiger]

Is it possible in mySQL to cross reference two tables?

I have a member table and a theme table. In my member table it has a theme field. This field holds an integer that indicates the ID from the theme table. How would i write a query that gets each row from the theme table, and sorts it by how many users in the member database have that theme set as theirs?

[Lars_Berg]

select t.themeid, count(userid) as frequency 
   from themes t left join users u 
  on t.themeid = u.themeid 
  group by t.themeid 
  order by frequency desc

Just guessing your object names.

[blacktiger]

thanx a ton!