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Comparison Query Operators
Comparison Query Operators
Query operators compare and reference document fields when you filter in find() or other query methods.
The comparison operators
| Operator | Meaning |
|---|---|
| $eq | Equal to |
| $ne | Not equal to |
| $gt | Greater than |
| $gte | Greater than or equal to |
| $lt | Less than |
| $lte | Less than or equal to |
| $in | Matches any value in an array |
Using them
// Posts with exactly 3 likes
db.posts.find({ likes: { $eq: 3 } })
// Posts with more than 1 like
db.posts.find({ likes: { $gt: 1 } })
// Posts with 1 or fewer likes
db.posts.find({ likes: { $lte: 1 } })
// Posts with a category of News or Technology
db.posts.find({ category: { $in: ["News", "Technology"] } })
// Posts where likes is NOT 3
db.posts.find({ likes: { $ne: 3 } })Implicit equality
A plain field/value query like { category: "News" } is shorthand for { category: { $eq: "News" } }.
TL;DR
$eq,$ne,$gt,$gte,$lt,$lte,$incompare field values.{ field: value }is the same as{ field: { $eq: value } }.$inmatches if the value is in a given array.