MySQL: Another max per group? Two tables -

my database tracks sections users have completed:

table 'users':

id    user_id    sections_id //  4         46              1  5         46              2  6         46              4  7         46              5 // 

table 'sections':

id    header_id    name  1            1     1/3  2            1     2/3  3            1     3/3  4            2     1/3  5            2     2/3  6            2     3/3 

the following query

select a.sections_id       ,b.header_id users join sections b on a.sections_id = b.id a.user_id = 46; // a.user_id can user_id, added clarity 

gives me:

sections_id    header_id           1            1           2            1           4            2           5            2 

what want max section id per header particular user, know section need serve user:

sections_id    header_id           2            1           5            2 

i'm assuming max per group problem, can't quite head around solution. throw data php , parse out there, seems should able via sql. tia!

this simple group by query:

select s.header_id, max(u.sections_id) users u join      sections s      on u.sections_id = s.id u.user_id = 46 group s.header_id; 

i changed aliases initials of table. makes query easier follow.

edit: sqlfiddle here: http://sqlfiddle.com/#!2/dbb5a/2