mongodb: finding the highest numeric value of a column

Question

I have MongoDB collection of documents containing several fields. One of the columns/fields should be numeric only, but some of these fields contain non-numerical (corrupt)

Answer 1

You can use aggregate function to get maximum number from collections like this.

$data=$collection->aggregate(array
                    ( '$group'=> 
                        array('_id'=>'',
                            'age'=>array('$max'=>'$age'.)
                        )
                    )
            );