MongoDB的查询方法

db.blogs.insert([
  {
    "author": "张三",
    "title": "MongoDB简介",
    "content": "它是介于关系型数据库和非关系型数据库之间的一种NoSQL数据库，用C++编写，是一款集敏捷性、可伸缩性、扩展性于一身的高性能的面向文档的通用数据库",
    "tags": [
      "MongoDB",
      "NoSQL"
    ],
    "comment": [
      {
        "name": "Jack",
        "detail": "Good！",
        "date": ISODate("2015-07-09 09:55:49")
      },
      {
        "name": "Tom",
        "detail": "Hello World！",
        "date": ISODate("2015-07-09 18:12:35")
      },
      {
        "name": "Alice",
        "detail": "你好，Mongo！",
        "date": ISODate("2015-07-10 20:30:30")
      }
    ],
    "readCount": 154
  },
  {
    "author": "李四",
    "title": "1+1等于几",
    "content": "有的人说1+1=2，因为这是老师从小告诉我们的；而有的人说1+1=11，这是两个1的组合；但是有些人就认为1+1=1，他们觉得1个团队加上另一个团队，会组成了一个更强大的团队！",
    "tags": [
      "story",
      "rule",
      "数学"
    ],
    "comment": [
      {
        "name": "王小光",
        "detail": "每个人心里边都有自己的答案。",
        "date": ISODate("2015-07-10 11:45:57")
      }
    ],
    "readCount": 367
  },
  {
    "author": "李四",
    "title": "如何写一篇好的博客？",
    "content": "1、目标；2、坚持；3、分享；4、学习；5、提高",
    "tags": null,
    "comment": [
      {
        "name": "小明",
        "detail": "ComeOn!!!!",
        "date": ISODate("2015-07-10 14:49:06")
      },
      {
        "name": "Nike",
        "detail": "终身学习！",
        "date": ISODate("2015-07-11 10:22:36")
      },
      {
        "name": "小红",
        "detail": "贵在坚持吧、",
        "date": ISODate("2015-07-12 12:12:12")
      }
    ],
    "readCount": 1489,
    "isTop": true
  }
])

Test Data

db.blogs.find()
或
db.blogs.find({})

注：查询一个文档：db.blogs.findOne()

db.blogs.find({},{"title":1,"content":1,"_id":0})

db.blogs.find({"author":"张三"})
或
db.blogs.find({"author":{"$eq":"张三"}})

db.blogs.find({"author":{"$ne":"张三"}})

db.blogs.find({"author":"张三","title":"MongoDB简介"})

db.blogs.find({"readCount":{"$gte":200,"$lt":1000}})

db.blogs.find({"$or":[{"author":"张三"},{"author":"李四"}]})

db.blogs.find({"tags":{"$in":["NoSQL","数学"]}})

db.blogs.find({"tags":{"$nin":["NoSQL","数学"]}}) //不包含

db.blogs.find({"tags":null})

db.blogs.find({"content":/1/})

db.blogs.find({"tags":{"$all":["story","rule"]}})

db.blogs.find({"tags.0":"MongoDB"})

db.blogs.find({"tags":{"$size":3}})

db.blogs.find({"comment.name":"Jack"})

db.blogs.find({}).skip(2).limit(2).sort({"readCount":-1})