MongoDB, select all entries where inner data-count is greater then zero

Question

I have something like this one.

{
    "title" : "",
    "source" : {
        "object" : "some",
        "group" : "some
        "data" : []
    }
}

"source.data" or "source" can be undefined at all.

So now I need to select all objects that has count(xxx.source.data) > 0 . How can I do this query? I search for count() and xxx.length (method\property) but still can't understand how to use them in my case.

Added:

.find({"source.data": {$exists: true, $size: {$gt: 1}}})

Parvin Gasimzade · Accepted Answer · 2013-10-07T11:00:35.473

3

You can do it as follows :

db.myObject.find({$and:[{"source.data":{$exists:true}},{"source.data":{$not:{$size:0}}}]})

From the mongoDB documentation, it says $size operator does not accept range queries.

$size does not accept ranges of values. To select documents based on fields with different numbers of elements, create a counter field that you increment when you add elements to a field.

For greater queries, you can use list index. You can use the following query to find the documents that has data size > 10.

db.myObject.find({$and:[{"source.data":{$exists:true}},{"source.data.10" : {$exists:true}}]})

edited Oct 07 '13 at 11:00

answered Oct 07 '13 at 10:09

Parvin Gasimzade

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It doesn't work if "source" or "source.data" not defined. (PS: Edited top message.) – user1954544 Oct 07 '13 at 10:16
I tried this one. (added to top) So it check existence but not selecting 'size is greater then', where can be trouble? – user1954544 Oct 07 '13 at 10:22
I have updated query. Try this one. It checks existence & size of the data array. – Parvin Gasimzade Oct 07 '13 at 10:29
Yes it works, but can you describe how to set 'greater then' ? For example want to select all where count > 10 ... – user1954544 Oct 07 '13 at 10:37

MongoDB, select all entries where inner data-count is greater then zero

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