$include

语法

{ <字段名1>: { $include: <0|非0> }, <字段名2>: { $include: <0|非0>, ... } }

说明

$include 可以指定选择或移除某个字段。

示例

在集合 sample.employee 插入如下记录：

> db.sample.employee.insert( { "_id": 1, "class": 1, "students": [ { "name": "ZhangSan", "age": 18 }, { "name": "LiSi", "age": 19 }, { "name": "WangErmazi", "age": 18 } ] } )

• 查询集合 sample.employee，指定选择 students 字段

  > db.sample.employee.find( {}, { "students": { "$include": 1 } } )
  {
    "students": [
      {
        "name": "ZhangSan",
        "age": 18
      },
      {
        "name": "LiSi",
        "age": 19
      },
      {
        "name": "WangErmazi",
        "age": 18
      }
    ]
  }
  Return 1 row(s).

• 查询集合 sample.employee，指定移除 students 字段

  > db.sample.employee.find( {}, { "students": { "$include": 0 } } )
  {
    "_id": 1,
    "class": 1
  }