如何在mongodb中指定var字段查找

Question

In mongodb, I want to find a document which exist a field returned by a function. for example:

var field = func()
var cur = db.test.find({field:{$exists:1}}).limit(1)

Mongodb to find a document has a field named "field", but I want to find a document has a field named the value of the var "field". what shoud I do. Thankd you very much.

Answer 1

Use this

db.CollectionName.find({},{FieldName:1})

in case I want to have results of students who have field named age in their document.

db.CollectionName.find({},{age:1}) // will result all documents with age in their field