I have the following query
db.runCommand(
{"text":"item","search":"\"price\" ",
"project":{"_id":1},
"limit":1,
"filter":{"quotes":{"$not":{"$size":0}}}}
);
But the filter part is taking a long time. For your understanding, "quotes" is a simple array of embeded documents. Is it possible to create an index to find all elements having at least one quote quickly?
EDIT: To be more specific: The question is not only about "how to query" but "how to make a useful index".
I think the quicker way is this one:
db.collection.find({array: {$elemMatch: {$exists: true}}})