readingsfilter-in-findwithrelated-parent

Using a readingsFilter in the parent section of a findWithRelated query

Insert a readingsFilter in the parent section of a $findWithRelated query to return telemetry items whose readings match your query and then a related collection query, such as their relationship to assets on a certain floor number.

Structure your $findWithRelated query as follows:

{
  "$findWithRelated": {
    "parent": {
      "collectionDesc": {
        "<property to identify telemetry collections>": "<value>"
      },
      "query": {
        //<simple query to find parent related items in the collections 
        //you describe in parent.collectionDesc>            
      },
      "readingsFilter": {
        "query": {
          //<Valid simple query to filter parent telemetry item query for 
          //telemetry items that match this telemetry reading query> 
        },
      }
    },
    "related": [
      {
        "relatedDesc": {
          "<property to identify related collections by, in this case asset collections>": "<value>"
        },
        "as": "asset",
        "query": {
          //<simple query to find related items in the collections you 
          //describe in related.relatedDesc. In this example, we want to 
          //query the first floor property>    
        }
      }
    ]
  }
}

The following code example returns a list of sensors that recorded a temperature above 11℃ on or after 09:00, December 1st, 2021, and are on the first floor:

Example request

{
  "$findWithRelated": {
    "parent": {
      "collectionDesc": {
        "_userItemId": "tempsensor_2ZoU1RwTKm"
      },
      "options": {
        "project": {
          "_sourceId": 1
        }
      },
      "query": {
        "dtType": "Temprature Sensor"
      },
      "readingsFilter": {
        "query": {
          "$and": [
            {
              "temp": {
                "$gte": 11
              }
            },
            {
              "_ts": {
                "$gte": "2021-12-01T09:00:00.000Z"
              }
            }
          ]
        }
      }
    },
    "related": [
      {
        "relatedDesc": {
          "_relatedUserType": "iaf_ext_asset_coll",
          "_isInverse": true
        },
        "as": "asset",
        "query": {
          "properties.Containing Floor.val": 1
        }
      }
    ]
  }
}

Example response

{
  "_list": [
    {
      "_uri": "/nameduseritems/634cc91c9d34dd31017382d3",
      "_name": "Temperature Sensors Collection",
      "_userType": "iaf_telemetry_timeseries",
      "_tipId": "634cc91c9d34dd31017382d4",
      "_versions": [
        {
          "_userItemDbId": "634cc91c9d34dd31017382d3",
          "_relatedItems": {
            "_pageSize": 1,
            "_list": [
              {
                "_sourceId": "a2e052a6-9126-21d5-7301-0000863f27ad-3450121",
                "_id": "634ccbe19d34dd31017382dc",
                "asset": {
                  "_pageSize": 1,
                  "_list": [
                    {
                      "Asset Name": "AHU-1",
                      "_id": "634cd93a9d34dd31017382e2",
                      "_metadata": {
                        "_updatedById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
                        "_createdAt": 1665980730755,
                        "_createdById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
                        "_updatedAt": 1665980730755
                      },
                      "properties": {
                        "Room Number": {
                          "val": 1
                        }
                      },  
                      "Containing Floor": {
                        "val": 1
                      }
                    }
                  ],
                  "_offset": 0,
                  "_total": 1
                }
              }
            ],
            "_offset": 0,
            "_total": 1
          },
          "_id": "634cc91c9d34dd31017382d4",
          "_isTip": true,
          "_metadata": {
            "_updatedById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
            "_createdAt": 1665976605041,
            "_createdById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
            "_updatedAt": 1665976605041
          },
          "_version": 1
        }
      ],
      "_irn": "itemsvc:nameduseritem:634cc91c9d34dd31017382d3",
      "_namespaces": [
        "Lnt_GglJp74V"
      ],
      "_nextVersion": 2,
      "_shortName": "tempsensor",
      "_tipVersion": 1,
      "_versionsCount": 1,
      "_itemClass": "NamedTelemetryCollection",
      "_userItemId": "tempsensor_2ZoU1RwTKm",
      "_id": "634cc91c9d34dd31017382d3",
      "_description": "Temperature Sensor IoT",
      "_metadata": {
        "_updatedById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
        "_createdAt": 1665976604777,
        "_createdById": "057ce6fd-a306-4bdc-8514-0a45c453f7ec",
        "_updatedAt": 1665976604777
      },
      "_kind": "collection"
    } 
  ],  
  "_time": "135ms"
}