I got a mongodb collection which items has create_time and delete_time field.I want a Aggregation
<p>I want a Aggregation.(or does aggregation can solve my question?)</p>

<h3><em>for example:</em></h3>

<p>There is a timestamp, if one item's create_time less than the timestamp and the delete_time large than the timestamp, it count 1, loop all items,  i can get the count in the timestamp, a series of count is what i needed.</p>

<p>This process too slow in my app.</p>

<p>Can mongodb aggregation help me? thanks</p>