get a mongo document based in two different values - mongodb

Question

I have the following document structure
{
"_id" : "aaa0001",
"path" : "/some/path",
"information" : {
"name" : "info"
},
"colors" : {
"colors" : [
{
"key" : "AAAA001",
"name" : "White"
},
{
"key" : "BBBB002",
"name" : "Black"
}
]
}
}
the idea is that I have to return the document by the color key. I have two parameters the "path" and the "color", so, I was trying to make something like this
db.components.find(
{$and:[
{"path" : "/some/path"},
{"colors":{"colors" : {$elemMatch: { "key" : "AAAA001" } } } }
]})
I'm getting the following message "Script is executed successfully, but there is no results to show".
Can anyone give me some directions regarding this?
thanks

Answer 1

Use the following query:
db.components.find({
"path": "/some/path",
"colors.colors.key" : "AAAA001"
})
MongoDB expects query document to contain field-value pairs { <field>: <value> }. So, in your example you're querying for a document with colors field equal to:
{"colors" : {$elemMatch: { "key" : "AAAA001" } } }
As for $and and $elemMatch operators, you don't need them in such a simple query.
For more information read Query Documents.
Update
You can also select only matching subdocument from colors array using Positional Operator $:
db.components.find({
"path": "/some/path",
"colors.colors.key" : "AAAA001"
}, {
_id: 0,
"colors.colors.$": 1
})
Though, you won't be able to change your documents structure, thus getting
{ "colors" : { "colors" : [ { "key" : "AAAA001", "name" : "White" } ] } }