如何查找field1大于field2的文档? (Nodejs/猫鼬/MongoDB) [英] How to find documents where field1 is greater than field2? ( Nodejs/Mongoose/MongoDB)

问题描述

在执行查询时如何在比较中使用字段中的值?

How do you use values from fields in comparison when executing queries?

文档示例:

db.inventory.find( { qty: { $gt: 20 } } )

如何使用文档中的字段值而不是20，就像这样:

How can I use a field value from the document instead of 20, like so:

db.inventory.find( { qty: { $gt: field2 } } )

这是我要实现的目标:

var query = model.find();

var first = "field1";
var second = "field2";

query.where(first).gt(second);

我正在动态地构建查询，所以我需要在猫鼬中使用查询生成器.

I am building the query dynamicly, so I need to use the query-builder in mongoose.

Edid2:感谢下面的回答，这就是我解决问题的方法:

Edid2: Thanks to the answer below, this is how I solved my problem:

query.where({$where: "this."+first+" > this."+second});

推荐答案

请使用$ WHERE运算符尝试以下查询:

Please try the below query with $WHERE operator :

 db.inventory.find({$where: function() { 
  return ( this.field1 >   this.field2 ); } });

P.S:您可以在下面的链接中找到$ Where文档: http://docs.mongodb.org/manual/reference/operator/query/哪里/

P.S : you can find the $Where documnetation in below link : http://docs.mongodb.org/manual/reference/operator/query/where/

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