Use $ne (for "not equal") db.collection.find({ "fieldToCheck": { $exists: true, $ne: null } }). ... <看更多>

MongoDB stores documents in collections; the collections in databases. ... If a database does not exist, MongoDB creates the database when you first store ... ... <看更多>

I see similar results when tried on MongoDB v4.2.8 - using the posted info. In general, the $exists in a query filter uses the index on that field. ... <看更多>

mongodb index and exists. GitHub Gist: instantly share code, notes, and snippets. ... <看更多>

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