php - Create multidimensional array from table where duplicative IDs have the same parent Key -

i have table this:

--primary id---office id---- |----1-------|---10--------| |----2-------|---10--------| |----3-------|---20--------| |----4-------|---10--------| |----5-------|---20--------| ---------------------------- 

i want object/array this:

array = array(   "10" => array(       "primary id" => 1,       "primary id" => 2,       "primary id" => 4    ),   "20" => array(       "primary id" => 3,       "primary id" => 5    ) ) 

my query be:

select * table order office id 

is there better query case?
there simple , small method creating array above?

edit: using sql server this... sadly no group_concat etc... ):

thanks!

its better use listagg function . i.e.

select office id, listagg(primary id, ', ') table group office id order office id 

once result of above sql, can tokenise each row delimiter ',' , put tokenised data in array.