更多查询

简单的增删改查里面，查询这块名堂要多点

分页查询

单页 2 条文档，第一页 db.user.find().limit(2).skip(0)

miodb> db.user.find().limit(2).skip(2)
[
  {
    _id: ObjectId("641fbad6e438a9958f14131d"),
    name: 'hanamaru',
    age: 19,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131e"),
    name: 'makoto',
    age: 51,
    gender: '女'
  }
]

排序查询

miodb> db.user.find().sort({age:1})
[
  {
    _id: ObjectId("641fbad6e438a9958f14131c"),
    name: 'yui',
    age: 16,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131b"),
    name: 'akiyama',
    age: 17,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131d"),
    name: 'hanamaru',
    age: 19,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131e"),
    name: 'makoto',
    age: 51,
    gender: '女'
  }
]

miodb> db.user.find().sort({age:-1})
[
  {
    _id: ObjectId("641fbad6e438a9958f14131e"),
    name: 'makoto',
    age: 51,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131d"),
    name: 'hanamaru',
    age: 19,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131b"),
    name: 'akiyama',
    age: 17,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131c"),
    name: 'yui',
    age: 16,
    gender: '女'
  }
]

正则查询

# 查询名字里面包含 u 的文档
miodb> db.user.find({name:/u/})
[
  {
    _id: ObjectId("641fbad6e438a9958f14131c"),
    name: 'yui',
    age: 16,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131d"),
    name: 'hanamaru',
    age: 19,
    gender: '女'
  }
]

比较查询

操作	格式
等于	{<key>:<value>}
小于	{<key>:{$lt:<value>}}
小于或等于	{<key>:{$lte:<value>}}
大于	{<key>:{$gt:<value>}}
大于或等于	{<key>:{$gte:<value>}}
不等于	{<key>:{$ne:<value>}}

miodb> db.user.find({name:"miomiora"})
[
  {
    _id: ObjectId("641fba25e438a9958f14131a"),
    name: 'miomiora',
    age: 24,
    gender: '男'
  }
]

miodb> db.user.find({age:{$gt:20}})
[
  {
    _id: ObjectId("641fba25e438a9958f14131a"),
    name: 'miomiora',
    age: 24,
    gender: '男'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131e"),
    name: 'makoto',
    age: 51,
    gender: '男'
  }
]

包含查询

miodb> db.user.find({name:{$in:["hanamaru", "yui"]}})
[
  {
    _id: ObjectId("641fbad6e438a9958f14131c"),
    name: 'yui',
    age: 16,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131d"),
    name: 'hanamaru',
    age: 19,
    gender: '女'
  }
]

miodb> db.user.find({name:{$nin:["hanamaru", "yui"]}})
[
  {
    _id: ObjectId("641fbad6e438a9958f14131b"),
    name: 'akiyama',
    age: 17,
    gender: '女'
  },
  {
    _id: ObjectId("641fbad6e438a9958f14131e"),
    name: 'makoto',
    age: 51,
    gender: '女'
  }
]

条件查询

或 $or:[{},{},{}] 和 $and:[{},{},{}]

查询 name 为 yui 或 makoto 的文档，并且只显示 name 和 age（0为不显示，1为显示，其中_id默认显示）

miodb> db.user.find({$or:[{name:"yui"}, {name:"makoto"}]}, {_id:0, name:1, age:1})
[ { name: 'yui', age: 16 }, { name: 'makoto', age: 51 } ]

如果 or 只是为了筛选一个字段的话用 in 更方便