How to use aggrigation..?

[singhvikram704]

I have collection:

{ "_id" : ObjectId("56696db1429cbd907085cb08"), "attributes" : [ { "_id" : "5666cec9e4b0834319eac761", "name" : "Quantity", "value" : "1kg" }, "status" : "Active", "type" : "single" }

How i use aggregation in restheart like query:

db.products.aggregate({$group : { _id : "$Quantity"}})

Need help regarding this...

Thanx in advance

[ujibang]

Refer to Aggregation documentation section

In your case, you need to add the following metadata property to the collection products and you can then get the aggregated data at URI /db/products/_aggrs/myaggr (not the uri property)

"aggrs": [{
            "type": "pipeline",
            "uri": "myaggr",
            "stages": [ {"_$group": {"_id": "$Quantity"} } ]
        }]

[hemraj-sharma]

Hi, I can use aggregation through restheart successfully. Thank You very much for Your support. But in a particular case, when I have to use Match for inside the document or after the unwind. I am getting invalid BSON field name. For example: ------->>>>>>> [ {"$unwind": "$abc_Ids"},{ "$match" : { "abc_Ids.abcId" : ""}},...] <<<<<<<<--------- "works fine on the mongo shell." as will be used as======>

[ {"_$unwind": "$abcIds"},{ "$match" : { "abcIds.abcId" : {"$var": ""} }},...] in the aggrs variable.

I am getting error as ------------>>>>>>>>>>>>>>> "http status code": 500, "http status description": "Internal Server Error", "message": "Error handling the request", "_embedded": { "rh:exception": [ { "exception": "java.lang.IllegalArgumentException", "exception message": "Invalid BSON field name abc_Ids.abcId", "stack trace": [ "java.lang.IllegalArgumentException: Invalid BSON field name abc_Ids.abcId", " at org.bson.AbstractBsonWriter.writeName(AbstractBsonWriter.java:494)", <<<<<<<<<<<<<<<<<<<<<<<---------------------------------------------- Can you guide in this regard. Thanks. Regards, hemraj

[hemraj-sharma]

editted above content: ---------->>>>>>>>>> as will be used as======>

[ {"_$unwind": "$abcIds"},{ "$match" : { "abcIds.abcId" : {"$var": ""} }},...] in the aggrs variable. <<<<<<<------------

[ujibang]

as you can read in the documentation the aggregation operator must be prefixed with _

this is because in mongodb fields names cannot start with _

for example, to use $unwind you have to actually pass _$unwind in the aggregation definition

[hemraj-sharma]

I am already using in that way. For the same I again edited the query. But somehow they are being converted to the present view. I am using $match as $match and "$unwind" as $unwind. though I am getting the problem which I have asked for.

[ujibang]

Can you pease past the full json you used to create the aggregation?

Just in case since I had this issue in the past: are you using a command line tool in a terminal where $xxx is interpreted as an environment variable?

In case escape it \$xxx