Iam grouping a field, now I want to add where clause.
How to add where clause in following?
$query=array(
'aggregate'=>$this->table_name,
'pipeline'=> array(
array('$group'=> array('_id'=> array(
'name'=>'$name',
"{$field}"=>'$'.$field
))),
array('$group'=> array(
'_id'=>'$_id.'.$field,
'count'=> array('$sum'=>1)
))
)
);
$result=$mongo_db->command($query);