php - Merge two queries into single query -

i have function gets information database, namely amount of songs in songs table , amount of artists artists table have songs in song table:

function getinfo() {     try {         $q = $this->connection->prepare('select artist_id '.tbl_song.'');         $q->execute();         if ($q->rowcount() > 0) {             $songs = $q->rowcount();         } else {             $songs = '0';         }         $q = $this->connection->prepare('select id '.tbl_artist.' exists (select * '.tbl_song.' s a.id = s.artist_id)');         $q->execute();         if ($q->rowcount() > 0) {             $artists = $q->rowcount();         } else {             $artists = '0';         }         return "<span class='italic'>current songs: </span>".$songs." <span class='italic'>active artists: </span>".$artists;     } catch (pdoexception $e) {         echo results_error;         logerror($e->getmessage());     } } 

the first query gets amount of songs song table , returns rowcount variable. second query gets artist id artist table, if have songs in songs table. result of function return both values.

i want able have both these values returned single query. i've tried writing 1 query , fetching results , using count function amount of rows need doesn't seem work. don't know i'm going wrong here. also, pointless checking if row count > 0 if statement , storing in variable it'll return value '0' anyway? thanks.

this pretty easy. want join artist table , song table using artist id. join, want know number of distinct artist ids , song ids. query want this:

select count(distinct a.id) artists, count(distinct s.id) songs artists inner join songs s on s.artist_id = a.id; 

i highly recommend query right console of kind before plugging php. output single row looks this:

+---------+-------+ | artists | songs | +---------+-------+ |      20 |   150 | +---------+-------+ 

from php, need fetch one-row answer , use in response:

if ($q->rowcount() > 0) {     $c = $q->fetchobject();     $output = "<span class='italic'>current songs: </span>{$c->songs}<span class='italic'>active artists: </span>{$c->artists}"; }