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Query, Update, and Projection Operators Quick Reference

Query, Update, and Projection Operators Quick Reference¶

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Query Selectors
Update
Projection

This document contains a list of all operators used with MongoDB in version 2.2. See Core MongoDB Operations (CRUD) for a higher level overview of the operations that use these operators, and Query, Update, Projection, and Aggregation Operators for a more condensed index of these operators.

Query Selectors¶

Comparison¶

Note

To express equal to (e.g. =) in the MongoDB query language, use JSON { key:value } structure. Consider the following prototype:

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db.collection.find( { field: value } )

For example:

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db.collection.find( { a: 42 } )

This query selects all the documents the where the a field holds a value of 42.

You may combine comparison operators to specify ranges:

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db.collection.find( { field: { $gt: value1, $lt: value2 } } );

This statement returns all documents with field between value1 and value2.

Note

If the field contains an array and the query has multiple conditional operators, the field as a whole will match if either a single array element meets the conditions or a combination of array elements meet the conditions.

Example

Query a field that contains an array.

A collection students contains the following documents where the score field contains an array of values:

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{ "_id" : 1, "score" : [ -1, 3 ] }
{ "_id" : 2, "score" : [ 1, 5 ] }
{ "_id" : 3, "score" : [ 5, 5 ] }

Then, the following query:

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db.students.find( { score: { $gt: 0, $lt: 2 } } )

Will match the following documents:

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{ "_id" : 1, "score" : [ -1, 3 ] }
{ "_id" : 2, "score" : [ 1, 5 ] }

In the document with _id equal to 1, the score: [ -1, 3 ] as a whole meets the specified conditions since the element -1 meets the $lt: 2 condition and the element 3 meets the $gt: 0 condition.
In the document with _id equal to 2, the score: [ 1, 5 ] as a whole meets the specified conditions since the element 1 meets both the $lt: 2 condition and the $gt: 0 condition.

Logical¶

Element¶

JavaScript¶

Geospatial¶

Use the following operators within the context of $near:

$maxDistance

Use the following operators within the context of $within:

Array¶

Update¶

Fields¶

Array¶

Bitwise¶

$bit

Isolation¶

$isolated

Projection¶

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