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How would I get an array containing all values of a certain field for all of my documents in a collection?
db.collection:
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be6"), "x" : 1 } { "_id" : ObjectId("51a7dc7b2cacf40b79990be7"), "x" : 2 } { "_id" : ObjectId("51a7dc7b2cacf40b79990be8"), "x" : 3 } { "_id" : ObjectId("51a7dc7b2cacf40b79990be9"), "x" : 4 } { "_id" : ObjectId("51a7dc7b2cacf40b79990bea"), "x" : 5 } "db.collection.ListAllValuesForfield(x)" Result: [1,2,3,4,5]
Also, what if this field was an array?
{ "_id" : ObjectId("51a7dc7b2cacf40b79990be6"), "y" : [1,2] } { "_id" : ObjectId("51a7dc7b2cacf40b79990be7"), "y" : [3,4] } { "_id" : ObjectId("51a7dc7b2cacf40b79990be8"), "y" : [5,6] } { "_id" : ObjectId("51a7dc7b2cacf40b79990be9"), "y" : [1,2] } { "_id" : ObjectId("51a7dc7b2cacf40b79990bea"), "y" : [3,4] } "db.collection.ListAllValuesInArrayField(y)" Result: [1,2,3,4,5,6,1,2,3,4]
Additionally, can I make this array unique? [1,2,3,4,5,6]
643
You can select a single field in MongoDB using the following syntax: db. yourCollectionName. find({"yourFieldName":yourValue},{"yourSingleFieldName":1,_id:0});
To get distinct values, use distinct() in MongoDB. It finds the distinct values for a specified field across a single collection or view and returns the results in an array.
Find() Method. In MongoDB, find() method is used to select documents in a collection and return a cursor to the selected documents.
The $all operator selects the documents where the value of a field is an array that contains all the specified elements.
db.collection.distinct('x')
should give you an array of unique values for that field.
119
This would return an array of docs, containing just it's x value...
db.collection.find( { }, { x: 1, y: 0, _id:0 } ) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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