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$all

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$all

The $all operator selects the documents where the value of a field is an array that contains all the specified elements. To specify an $all expression, use the following prototype:

{ <field>: { $all: [ <value1> , <value2> ... ] } }

Behavior

Equivalent to $and Operation

Changed in version 2.6.

The $all is equivalent to an $and operation of the specified values; i.e. the following statement:

{ tags: { $all: [ "ssl" , "security" ] } }

is equivalent to:

{ $and: [ { tags: "ssl" }, { tags: "security" } ] }

Nested Array

Changed in version 2.6.

When passed an array of a nested array (e.g. [ [ "A" ] ] ), $all can now match documents where the field contains the nested array as an element (e.g. field: [ [ "A" ], ... ]), or the field equals the nested array (e.g. field: [ "A" ]).

For example, consider the following query [1]:

db.articles.find( { tags: { $all: [ [ "ssl", "security" ] ] } } )

The query is equivalent to:

db.articles.find( { $and: [ { tags: [ "ssl", "security" ] } ] } )

which is equivalent to:

db.articles.find( { tags: [ "ssl", "security" ] } )

As such, the $all expression can match documents where the tags field is an array that contains the nested array [ "ssl", "security" ] or is an array that equals the nested array:

tags: [ [ "ssl", "security" ], ... ]
tags: [ "ssl", "security" ]

This behavior for $all allows for more matches than previous versions of MongoDB. Earlier versions could only match documents where the field contains the nested array.

[1] The $all expression with a single element is for illustrative purposes since the $all expression is unnecessary if matching only a single element. Instead, when matching a single element, a “contains” expression (i.e. arrayField: element ) is more suitable.

Examples

The following examples use the inventory collection that contains the documents:

{
   _id: ObjectId("5234cc89687ea597eabee675"),
   code: "xyz",
   tags: [ "school", "book", "bag", "headphone", "appliance" ],
   qty: [
          { size: "S", num: 10, color: "blue" },
          { size: "M", num: 45, color: "blue" },
          { size: "L", num: 100, color: "green" }
        ]
}

{
   _id: ObjectId("5234cc8a687ea597eabee676"),
   code: "abc",
   tags: [ "appliance", "school", "book" ],
   qty: [
          { size: "6", num: 100, color: "green" },
          { size: "6", num: 50, color: "blue" },
          { size: "8", num: 100, color: "brown" }
        ]
}

{
   _id: ObjectId("5234ccb7687ea597eabee677"),
   code: "efg",
   tags: [ "school", "book" ],
   qty: [
          { size: "S", num: 10, color: "blue" },
          { size: "M", num: 100, color: "blue" },
          { size: "L", num: 100, color: "green" }
        ]
}

{
   _id: ObjectId("52350353b2eff1353b349de9"),
   code: "ijk",
   tags: [ "electronics", "school" ],
   qty: [
          { size: "M", num: 100, color: "green" }
        ]
}

Use $all to Match Values

The following operation uses the $all operator to query the inventory collection for documents where the value of the tags field is an array whose elements include appliance, school, and book:

db.inventory.find( { tags: { $all: [ "appliance", "school", "book" ] } } )

The above query returns the following documents:

{
   _id: ObjectId("5234cc89687ea597eabee675"),
   code: "xyz",
   tags: [ "school", "book", "bag", "headphone", "appliance" ],
   qty: [
          { size: "S", num: 10, color: "blue" },
          { size: "M", num: 45, color: "blue" },
          { size: "L", num: 100, color: "green" }
        ]
}

{
   _id: ObjectId("5234cc8a687ea597eabee676"),
   code: "abc",
   tags: [ "appliance", "school", "book" ],
   qty: [
          { size: "6", num: 100, color: "green" },
          { size: "6", num: 50, color: "blue" },
          { size: "8", num: 100, color: "brown" }
        ]
}

Use $all with $elemMatch

If the field contains an array of documents, you can use the $all with the $elemMatch operator.

The following operation queries the inventory collection for documents where the value of the qty field is an array whose elements match the $elemMatch criteria:

db.inventory.find( {
                     qty: { $all: [
                                    { "$elemMatch" : { size: "M", num: { $gt: 50} } },
                                    { "$elemMatch" : { num : 100, color: "green" } }
                                  ] }
                   } )

The query returns the following documents:

{
   "_id" : ObjectId("5234ccb7687ea597eabee677"),
   "code" : "efg",
   "tags" : [ "school", "book"],
   "qty" : [
             { "size" : "S", "num" : 10, "color" : "blue" },
             { "size" : "M", "num" : 100, "color" : "blue" },
             { "size" : "L", "num" : 100, "color" : "green" }
           ]
}

{
   "_id" : ObjectId("52350353b2eff1353b349de9"),
   "code" : "ijk",
   "tags" :