$et

语法

{ <字段名>: { $et: <值> } }

描述

指定相等条件，$et 匹配符匹配记录中某个字段的值等于指定的值。

示例

在集合 sample.employee 插入如下记录：

> db.sample.employee.insert( { "id": 1, "item": { "name": "Tom",  "code": "123" } } )
> db.sample.employee.insert( { "id": 2, "item": { "name": "Jack", "code": "123" } } )
> db.sample.employee.insert( { "id": 3, "item": { "name": "Mike", "code": "456" } } )
> db.sample.employee.insert( { "id": 4, "item": { "name": "Lucy", "code": "789" }, "phone": [ "135", "177" ] } )

• 查询 id 字段值等于 1 的记录

  > db.sample.employee.find( { "id": { "$et": 1 } } )
  {
    "_id": {
      "$oid": "5822b0472b4c38286d000009"
    },
    "id": 1,
    "item": {
      "name": "Tom",
      "code": "123"
    }
  }

  查询相当于：

  > db.sample.employee.find( { "id": 1 } )

• 匹配嵌套字段 name 的值等于“Jack”的记录

  > db.sample.employee.find( { "item.name": { "$et": "Jack" } } )
  {
    "_id": {
      "$oid": "5822b04b2b4c38286d00000a"
    },
    "id": 2,
    "item": {
      "name": "Jack",
      "code": "123"
    }
  }
  Return 1 row(s).

  查询相当于：

  > db.sample.employee.find( { "item.name": "Jack" } )

• 匹配数组元素

  > db.sample.employee.find( { "phone": { "$et": "135" } } )
  {
        "_id": {
      "$oid": "5822b0562b4c38286d00000c"
    },
    "id": 4,
    "item": {
      "name": "Lucy",
      "code": "789"
    },
    "phone": [
      "135",
      "177"
    ]
  }
  Return 1 row(s).

  查询相当于：

  > db.sample.employee.find( { "phone": "135" } )