db={"temperature":[{"WorkstationId":1,"DtEvent":ISODate("2020-01-01T00:00:10.723Z"),"ParameterName":"temperature","ParameterValue":232.1},{"WorkstationId":1,"DtEvent":ISODate("2020-01-01T00:00:56.622Z"),"ParameterName":"temperature","ParameterValue":231.9}],"pressure":[{"WorkstationId":1,"DtEvent":ISODate("2020-01-01T00:00:10.725Z"),"ParameterName":"pressure","ParameterValue":3276.69},{"WorkstationId":1,"DtEvent":ISODate("2020-01-01T00:00:56.641Z"),"ParameterName":"pressure","ParameterValue":3276.69},{"WorkstationId":1,"DtEvent":ISODate("2020-01-01T00:01:42.622Z"),"ParameterName":"pressure","ParameterValue":3276.69}]}

db.pressure.aggregate([{$lookup:{from:"temperature",let:{dt_event:{$dateToString:{date:"$DtEvent",format:"%Y-%m-%dT%H:%M:%S"}}},pipeline:[{$match:{$expr:{$eq:["$$dt_event",{$dateToString:{date:"$DtEvent",format:"%Y-%m-%dT%H:%M:%S"}}]}}}],as:"temperature"}}])