follow the consultation that should work
SELECT (select count(paciente_id) from agenda where paciente_id='0') as id0, (select count(paciente_id) from agenda where paciente_id<>'0') as idok from agenda;
no result just catch your var like this $resultado['id0']
for id=0 and $resultado['idok']
for ids <> 0
if necessary with date
SELECT (select count(paciente_id) from agenda where paciente_id='0' and dia_consulta='$data') as id0, (select count(paciente_id) from agenda where paciente_id<>'0' and dia_consulta='$data') as idok from agenda;
where the dia_query you exchange for your date field and the $date he your chosen date, Obs vc should treat the date appropriately for the query.
what date format you are saving ?
– Jasar Orion