は、次の書類を請求書のコレクションを考えてみましょうMongoDBの

Question

における文書の2つのフィールド間の比較：

{ "invoice_no" : "1001", "payable_amount" : 100, "paid_amount" : 50 } 
{ "invoice_no" : "1002", "payable_amount" : 200, "paid_amount" : 200 } 
{ "invoice_no" : "1003", "payable_amount" : 300, "paid_amount" : 150 } 
{ "invoice_no" : "1004", "payable_amount" : 400, "paid_amount" : 400 } 

それらの文書はpayable_amount> paid_amount

期待される結果が必要：

{ "invoice_no" : "1001", "payable_amount" : 100, "paid_amount" : 50 } 
{ "invoice_no" : "1003", "payable_amount" : 300, "paid_amount" : 150 } 

Answer 1

をあなたは$where operatorをこれに使用する例がたくさんありますが、集約フレームワークでこれを行うことができます。

db.collection.aggregate([ 
    { 
     "$addFields": { 
      "isPayableAmountGreater": { "$cmp": [ "$payable_amount", "$paid_amount" ] } 
     } 
    }, 
    { "$match": { "isPayableAmountGreater": 1 } } 
]) 

あるいは、さらに簡単と（おそらく不要）を作成せずにisPayableAmountGreater準属性：

db.collection.aggregate([ 
    { 
     "$redact": { 
      "$cond": [ 
       { "$gt": [ "$payable_amount", "$paid_amount" ] }, 
       "$$KEEP", 
       "$$PRUNE" 
      ] 
     } 
    } 
])