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db.external_S_P_FLAT_main_api.aggregate([{"$addFields":{"external_S_P_FLAT_main_api_data.pricing.cost_center":"$data.pricing.cost_center"}},{"$lookup":{from:"external_S_C_FLAT_main_api",let:{let_data__pricing__cost_center:{"$getField":"data.pricing.cost_center"}},pipeline:[{"$match":{"$expr":{"$and":[{"$eq":[{"$getField":"data.costcenter.cost_center"},"$$let_data__pricing__cost_center"]}]}}}],as:"from_external_S_C_FLAT_main_api"}},{"$unwind":{path:"$from_external_S_C_FLAT_main_api",preserveNullAndEmptyArrays:true}},{"$replaceRoot":{newRoot:{"$mergeObjects":["$from_external_S_C_FLAT_main_api","$$ROOT"]}}},{$unionWith:{coll:"external_S_C_FLAT_main_api",pipeline:[{"$match":{"$expr":{"$and":[{"$ne":[{"$getField":"data.costcenter.cost_center"},false]}]}}},{$project:{_id:0}}]}},{"$project":{_id:0,"external_S_P_FLAT_main_api_data.pricing.controlling_area":0,"external_S_P_FLAT_main_api_data.pricing.cost_center":0,external_S_P_FLAT_main_api_IS_INVALID:0,external_S_P_FLAT_main_api_USER_ID:0,from_external_S_C_FLAT_main_api:0}}])