I currently need to perform a query with MongoDB using the aggregation framework. Here is the diagram of my documents as well as the request I wish to make.
tools { "_id": 1, "code": "TOOL_1", "label": "Tool 1", "items": [ { "code_it": TOOL_1_TT_1, "label": "Tool TT 1", "value": 25.00 }, { "code_it": TOOL_1_TT_2, "label": "Tool TT 2", "value": 17.00 }, { "code_it": TOOL_1_TT_3, "label": "Tool TT 3", "value": 17.00 }, ] } results_tools { "_id": 1, results: [ { "code_it": "TOOL_TT_2", "owner": "person_A" }, { "code_it": "TOOL_TT_3", "owner": "person_D" }, { "code_it": "TOOL_TT_2", "owner": "person_C" }, ] } db.results_tools.aggregate([ { $unwind: "$results" }, { $lookup: { from: "tools", let: { res_cod_it: "$code_it" }, pipeline: [ { $unwind: "$items" }, { $match: { $expr: { $eq: [ "$$res_cod_it", "$code_it" ] } } } ], as: "item" } }, { $project: { "owner": 1, "el.code": "code_it", "el.label": "item.label", "el.value": "item.label" } } ]); I would like to be able to retrieve the label of the tool based on the results. However, I have an error at runtime, so I wonder if using $unwind in the $lookup pipeline is possible.
Thank you for your answer. Laurent
