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I have two properties b and u that are arrays. I want my query to return me all documents that have at least 1 element in b that satisfies condition 1 or at least 1 element in u that satisfied condition 2.

My problem is that if condition 1 is satisfied, it will return me the array b with all elements that satisfy it, AND ALL the elements from u. Same with condition B.

I want: If there is an element in b that satisfied condition 1, return me that array with the elements that satisfy it. If not, empty array or exclude b. Same with condition 2 and u.

If no elements satisfy the conditions, exclude the document.

Discipol
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1 Answers1

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Unfortunately, you can't do that with MongoDB in a single step on the database server. You'll need to do it client side.

While you can project (documentation) your results to only include/exclude some fields (or the first matching result in an array for example as shown here), you can't conditionally do it based on a search with multiple arrays (and the projection operator returns only the first match, not just the results that match).

You might need to consider a different document/collection structure to meet your requirements. MongoDB doesn't have sub-document level filtering/searching yet.

WiredPrairie
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  • was afraid of that. i'll have to do some sort of a "pending" collection with lots of writes and reads. ty wired – Discipol Aug 25 '13 at 15:59