Database
db={"Materials":[{"MATERIAL":{"AS_MARA":{"MATNR":"456"}}},{"MATERIAL":{"AS_MARA":{"MATNR":"654"}}},{"MATERIAL":{"AS_MARA":{"MATNR":"000"}}}],"Orders":[{"OrderHead":{"AUFNR":"123","MATNR":"456"}},{"OrderHead":{"AUFNR":"321","MATNR":"654"}}],"SlittingPatterns":[{"STKO":{"RUNNR":"123"},"STPO":[{"AUFNR":"123"},{"AUFNR":"321"}]}]}
Query
db.SlittingPatterns.aggregate([{"$lookup":{"from":"Orders","localField":"STPO.AUFNR","foreignField":"OrderHead.AUFNR","as":"ORDERS"}},{"$lookup":{"from":"Materials","localField":"ORDERS.OrderHead.MATNR","foreignField":"MATERIAL.AS_MARA.MATNR","as":"MATERIALS"}}])