Hierarchical Query Question (PHP)

Can anyone tell me how to write the query described @
http://stackoverflow.com/questions/33402831/count-descendants-in-hierarchical-query
?

The answer's very thorough, but I don't know how to string two queries and
a function together like that. This doesn't work:

$sql = "select * from gz_life_mammals;";

create function tax_rank(id integer) returns text as $$
select case id
when 1 then 'Classes'
when 2 then 'Orders'
when 3 then 'Families'
when 4 then 'Genera'
when 5 then 'Species'
end;
$$ language sql;

$sql = "with recursive hier(taxon,parent_id) as (
select m.taxon, null::integer
from gz_life_mammals m
where taxon='Mammalia' --<< substitute me
union all
select m.taxon, m.parent_id
from hier, gz_life_mammals m
where m.parent=hier.taxon
)
select tax_rank(parent_id),
count(*) num_of_desc
from hier
where parent_id is not null
group by parent_id
order by parent_id;";

Thanks.