Hello I need to insert a js variable in my projection. How to do ? The following statement does not work. Thanks for help :wink: let sensor = sensorName // I use node Driver. collection.find({ _id : ObjectID(boatId)} , { $project : { 'data.sensors.0.$$sensor' : 1} }).toArray((err , r…

[image] steevej: 'data.sensors.0.' + sensor Driver code (like the above js string concat) can be mixed with mongo code,but the driver code runs before sending the query to mongo. sensor is a js variable not a mongo variable Its helpful to use driver code to generate mongo queries many times…

Upsylon_Developpemen (Upsylon Developpement) December 7, 2020, 6:57am 10

Thanks Steeve ! your solution is more simple effectivly !

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Insert js variables in projection?