Exercise: Aggregation
demo->whisky;
$name = 'Michael';
$res = $c->aggregate( [
[ '$match' => [ 'notes.user_name' => $name ] ],
[ '$unwind' => '$notes' ],
[ '$match' => [ 'notes.user_name' => $name ] ],
[ '$group' => [
'_id' => '$notes.user_name',
'notes' => [
'$addToSet' => [
'whisky' => '$name',
'note' => '$notes.note',
'rating' => '$notes.rating'
]
]
] ],
[ '$sort' => [ 'notes.rating' => -1 ] ],
] );
var_dump( $res['result'] );
?>]]>