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redis和MongoDB数据库的基础操作_mongodb redis结合使用

作者：算法构造者 | 2024-02-02 20:15:21

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mongodb redis结合使用

目录

一、NOSQL数据库相关操作

1、string类型数据的命令操作

2、listl类型数据的命令操作

3、hash类型数据的命令操作

4、key相关的命令操作

二、MongoDB

1. 创建一个数据库 名字grade 

2. 数据库中创建一个集合名字 class

3. 集合中插入若干数据 文档格式如下

4、查询（查找）

4.1、查看班级所有人信息

4.2、查看班级中年龄为8岁的学生信息

4.3、查看年龄大于10岁的学生信息

4.4、查看年龄在 4---8岁之间的学生信息 

4.5、找到年龄为6岁且为男生的学生

4.6、找到年龄小于7岁或者大于10岁的学生

4.7、找到年龄是8岁或者11岁的学生

4.8、找到兴趣爱好有两项的学生

4.9、找到兴趣爱好有draw的学生

4.10、找到既喜欢画画又喜欢跳舞的学生

4.11、统计爱好有三项的学生人数

4.12、找出本班年龄第二大的学生

4.13、查看学生的兴趣范围

4.14、将学生按年龄排序找到年龄最大的三个

4.15、删除所有 年龄大于12或者小于4岁的学生

5、增加、更新、删除、统计

5.1、将小红的年龄变为8岁 兴趣爱好变为 跳舞 画画

5.2、追加小明兴趣爱好  唱歌

5.3、小王兴趣爱好增加  吹牛 打篮球

5.4、小李增加爱好，跑步和唱歌，但是不要和以前的重复

5.5、该班所有同学年龄加1

5.6、 删除小明的sex属性

5.7、删除小李兴趣中的第一项

5.8、 将小红兴趣中的画画爱好删除

6、增加分数域 并进行下列操作

6.1、按照性别分组统计每组人数

6.2、 按照姓名分组，过滤出有重名的同学

6.3、统计每名男生的语文成绩

6.4、将女生按照英语分数降序排列

一、NOSQL数据库相关操作

1、string类型数据的命令操作

  1. 1） 设置键值：
  2. 127.0.0.1:6379> set key1 1
  3. OK
  4.  
  5. （2） 读取键值：
  6. 127.0.0.1:6379> get key1
  7. "1"
  8.  
  9. （3） 数值类型自增1：
  10. 127.0.0.1:6379> incr key1
  11. (integer) 2
  12.  
  13. （4） 数值类型自减1：
  14. 127.0.0.1:6379> strlen key1
  15. (integer) 1
  16.  
  17. （5） 查看值的长度：
  18. 127.0.0.1:6379> set key2 hello
  19. OK
  20. 127.0.0.1:6379> get key2
  21. "hello"
  22. 127.0.0.1:6379> strlen key2
  23. (integer) 5

2、listl类型数据的命令操作

  1. （1）对列表city插入元素：Shanghai Suzhou Hangzhou
  2. 127.0.0.1:6379> lpush city Shanghai Suzhou Hangzhou
  3. (integer) 
  4. 	
  5. （2）将列表city里的头部的元素移除
  6. 127.0.0.1:6379> lpop city 
  7. "Hangzhou"
  8.  
  9. （3）将name列表的尾部元素移除到number列表的头部
  10. 127.0.0.1:6379> rpush name 1 2 3
  11. (integer) 3
  12. 127.0.0.1:6379> rpush number 0
  13. (integer) 1
  14. 127.0.0.1:6379> rpoplpush name number
  15. "3"
  16. 127.0.0.1:6379> lrange name 0 -1
  17. 1) "1"
  18. 2) "2"
  19. 127.0.0.1:6379> lrange number 0 -1
  20. 1) "3"
  21. 2) "0"
  22.  
  23. （4） 对一个已存在的列表插入新元素
  24. 127.0.0.1:6379> rpushx number 4
  25. (integer) 3
  26. 127.0.0.1:6379> lrange number 0 -1
  27. 1) "3"
  28. 2) "0"
  29. 3) "4"
  30.  
  31. （5）查看list的值长度
  32. 127.0.0.1:6379> llen list
  33. (integer) 7

3、hash类型数据的命令操作

如果中文输入显示不出来可以在登录的时候加上后缀 ：  --raw

  1. (1） 设置一个hash表，order表里包括的键值信息有：id：1,customer_name：张三
  2. 127.0.0.1:6379> hmset order id 1 customer_name "张三"
  3. OK
  4. 127.0.0.1:6379> hvals order
  5. 1
  6. 张三
  7.  
  8. （2） 创建一个hash表，表里的键值批量插入
  9. 127.0.0.1:6379> hmset order id 2 customer_name "李四" id1 3 customer_name1 "王五"
  10. OK
  11. 127.0.0.1:6379> hvals order
  12. 2
  13. 李四
  14. 3
  15. 王五
  16.  
  17. （3） 获取order对应的map的所有key
  18. 127.0.0.1:6379> hkeys order
  19. id
  20. customer_name
  21. id1
  22. customer_name1
  23.  
  24. （4） 获取order对应的map的键值数量
  25. 127.0.0.1:6379> hlen order
  26. 4
  27.  
  28. （5） 获取order表里的id值
  29. 127.0.0.1:6379> hget order id
  30. 2
  31. 127.0.0.1:6379> hget order id1
  32. 3

4、key相关的命令操作

  1. (1) 查看key是否存在
  2. 127.0.0.1:6379> exists key
  3. 1
  4.  
  5. (2) 查找满足pattern的keys
  6. 127.0.0.1:6379> keys pattern
  7.  
  8. (3) 查看key的超时时间
  9. 127.0.0.1:6379> ttl key
  10. -1
  11.  
  12. (4) 遍历key
  13. 127.0.0.1:6379> keys *
  14. key1
  15. list
  16. order
  17. key2
  18. city
  19. Shanghai
  20. name
  21. key
  22. orders
  23. number

二、MongoDB

1. 创建一个数据库 名字grade 

  1. > use grade
  2. switched to db grade

2. 数据库中创建一个集合名字 class

3. 集合中插入若干数据 文档格式如下

｛name:'zhang',age；10,sex:'m',hobby:['a','b','c']｝
hobby: draw  sing  dance  basketball football  pingpong  computer

  1. > db.class.insertMany(
  2. ... [{name:"李四",age:8,sex:"男",hobby:['draw']},
  3. ... {name:"赵四",age:5,sex:"女",hobby:['draw','dance']},
  4. ... {name:"王五",age:6,sex:"男",hobby:['sing','computer','pingpong']},
  5. ... {name:"钱七",age:11,sex:"女",hobby:['dance']}]
  6. ... )
  7. {
  8. 	"acknowledged" : true,
  9. 	"insertedIds" : [
  10. 		ObjectId("64a699bfaef644e7b3f5def9"),
  11. 		ObjectId("64a699bfaef644e7b3f5defa"),
  12. 		ObjectId("64a699bfaef644e7b3f5defb"),
  13. 		ObjectId("64a699bfaef644e7b3f5defc")
  14. 	]
  15. }
  16. > db.class.find()
  17. { "_id" : ObjectId("64a6988caef644e7b3f5def8"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "dance" ] }
  18. { "_id" : ObjectId("64a699bfaef644e7b3f5def9"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  19. { "_id" : ObjectId("64a699bfaef644e7b3f5defa"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  20. { "_id" : ObjectId("64a699bfaef644e7b3f5defb"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }
  21. { "_id" : ObjectId("64a699bfaef644e7b3f5defc"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }

4、查询（查找）

4.1、查看班级所有人信息

  1. > db.class.find()
  2.  
  3. { "_id" : ObjectId("64a6988caef644e7b3f5def8"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "dance" ] }
  4. { "_id" : ObjectId("64a699bfaef644e7b3f5def9"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  5. { "_id" : ObjectId("64a699bfaef644e7b3f5defa"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  6. { "_id" : ObjectId("64a699bfaef644e7b3f5defb"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }
  7. { "_id" : ObjectId("64a699bfaef644e7b3f5defc"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }
  8. { "_id" : ObjectId("64a69a00aef644e7b3f5defd"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  9. { "_id" : ObjectId("64a69a00aef644e7b3f5defe"), "name" : "侯九", "age" : 13, "sex" : "男", "hobby" : [ "basketball" ] }
  10. { "_id" : ObjectId("64a69a00aef644e7b3f5deff"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

4.2、查看班级中年龄为8岁的学生信息

  1. > db.class.find({age:8})
  2. { "_id" : ObjectId("64a699bfaef644e7b3f5def9"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }

4.3、查看年龄大于10岁的学生信息

  1. > db.class.find({age:{$gt:10}})
  2.  
  3. { "_id" : ObjectId("64a699bfaef644e7b3f5defc"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }
  4. { "_id" : ObjectId("64a69a00aef644e7b3f5defe"), "name" : "侯九", "age" : 13, "sex" : "男", "hobby" : [ "basketball" ] }

4.4、查看年龄在 4---8岁之间的学生信息 

  1. > db.class.find({age:{$gte:4,$lte:8}})
  2.  
  3. { "_id" : ObjectId("64a699bfaef644e7b3f5def9"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  4. { "_id" : ObjectId("64a699bfaef644e7b3f5defa"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  5. { "_id" : ObjectId("64a699bfaef644e7b3f5defb"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }
  6. { "_id" : ObjectId("64a69a00aef644e7b3f5defd"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  7. { "_id" : ObjectId("64a69a00aef644e7b3f5deff"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

4.5、找到年龄为6岁且为男生的学生

  1. > db.class.find({"$and":[{age:6},{"sex":"男"}]})
  2.  
  3. { "_id" : ObjectId("64a699bfaef644e7b3f5defb"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }

4.6、找到年龄小于7岁或者大于10岁的学生

  1. > db.class.find({"$or":[{age:{$gt:10}},{age:{$lt:7}}]})
  2.  
  3. { "_id" : ObjectId("64a699bfaef644e7b3f5defa"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  4. { "_id" : ObjectId("64a699bfaef644e7b3f5defb"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }
  5. { "_id" : ObjectId("64a699bfaef644e7b3f5defc"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }
  6. { "_id" : ObjectId("64a69a00aef644e7b3f5defd"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  7. { "_id" : ObjectId("64a69a00aef644e7b3f5defe"), "name" : "侯九", "age" : 13, "sex" : "男", "hobby" : [ "basketball" ] }

4.7、找到年龄是8岁或者11岁的学生

  1. > db.class.find({"$or":[{age:8},{age:11}]})
  2.  
  3. { "_id" : ObjectId("64a699bfaef644e7b3f5def9"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  4. { "_id" : ObjectId("64a699bfaef644e7b3f5defc"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }

4.8、找到兴趣爱好有两项的学生

  1. > db.class.find({hobby:{$size:2}})
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e029"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  4. { "_id" : ObjectId("64a65d10ff846fd29644e02b"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  5. { "_id" : ObjectId("64a65d10ff846fd29644e02e"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  6. { "_id" : ObjectId("64a65d10ff846fd29644e030"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

4.9、找到兴趣爱好有draw的学生

  1. > db.class.find({hobby:'draw'})
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e029"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  4. { "_id" : ObjectId("64a65d10ff846fd29644e02a"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  5. { "_id" : ObjectId("64a65d10ff846fd29644e02b"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  6. { "_id" : ObjectId("64a65d10ff846fd29644e02e"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  7. { "_id" : ObjectId("64a65d10ff846fd29644e030"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

4.10、找到既喜欢画画又喜欢跳舞的学生

  1. > db.class.find({hobby:{$all:["draw","dance"]}})
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e02b"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  4. { "_id" : ObjectId("64a65d10ff846fd29644e030"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

4.11、统计爱好有三项的学生人数

  1. > db.class.find({hobby:{$size:3}})
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e02c"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }

4.12、找出本班年龄第二大的学生

  1. > db.class.find().sort({age:-1}).skip(1).limit(1)
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e02d"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }

4.13、查看学生的兴趣范围

  1. > db.class.distinct("hobby")
  2.  
  3. [ "basketball", "computer", "dance", "draw", "pingpong", "sing" ]

4.14、将学生按年龄排序找到年龄最大的三个

  1. > db.class.find().sort({age:-1}).limit(3)
  2.  
  3. { "_id" : ObjectId("64a65d10ff846fd29644e02f"), "name" : "侯九", "age" : 13, "sex" : "男", "hobby" : [ "basketball" ] }
  4. { "_id" : ObjectId("64a65d10ff846fd29644e02d"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }
  5. { "_id" : ObjectId("64a65d10ff846fd29644e029"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }

4.15、删除所有 年龄大于12或者小于4岁的学生

  1. > db.class.remove({"$or":[{age:{$lt:4}},{age:{$gt:12}}]})
  2.  
  3. WriteResult({ "nRemoved" : 1 })
  4.  
  5. > db.class.find()
  6.  
  7. { "_id" : ObjectId("64a65d10ff846fd29644e029"), "name" : "张三", "age" : 10, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  8. { "_id" : ObjectId("64a65d10ff846fd29644e02a"), "name" : "李四", "age" : 8, "sex" : "男", "hobby" : [ "draw" ] }
  9. { "_id" : ObjectId("64a65d10ff846fd29644e02b"), "name" : "赵四", "age" : 5, "sex" : "女", "hobby" : [ "draw", "dance" ] }
  10. { "_id" : ObjectId("64a65d10ff846fd29644e02c"), "name" : "王五", "age" : 6, "sex" : "男", "hobby" : [ "sing", "computer", "pingpong" ] }
  11. { "_id" : ObjectId("64a65d10ff846fd29644e02d"), "name" : "钱七", "age" : 11, "sex" : "女", "hobby" : [ "dance" ] }
  12. { "_id" : ObjectId("64a65d10ff846fd29644e02e"), "name" : "孙八", "age" : 4, "sex" : "男", "hobby" : [ "draw", "pingpong" ] }
  13. { "_id" : ObjectId("64a65d10ff846fd29644e030"), "name" : "熊十", "age" : 7, "sex" : "女", "hobby" : [ "draw", "dance" ] }

5、增加、更新、删除、统计

> db.class1.find()
{ "_id" : ObjectId("64a66525ff846fd29644e031"), "name" : "小红", "age" : 7, "sex" : "女", "hobby" : [ "pingpong", "dance" ] }
{ "_id" : ObjectId("64a66525ff846fd29644e032"), "name" : "小明", "age" : 8, "sex" : "男", "hobby" : [ "draw", "dance" ] }
{ "_id" : ObjectId("64a66525ff846fd29644e033"), "name" : "小李", "age" : 8, "sex" : "女", "hobby" : [ "draw", "dance" ] }
{ "_id" : ObjectId("64a66525ff846fd29644e034"), "name" : "小王", "age" : 9, "sex" : "男", "hobby" : [ "draw", "dance" ] }

5.1、将小红的年龄变为8岁 兴趣爱好变为 跳舞 画画

  1. > db.class1.update({name:"小红"},{'$set':{age:8,hobby:["跳舞","画画"]}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find({name:"小红"})
  5. { "_id" : ObjectId("64a66525ff846fd29644e031"), "name" : "小红", "age" : 8, "sex" : "女", "hobby" : [ "跳舞", "画画" ] }

5.2、追加小明兴趣爱好  唱歌

  1. > db.class1.update({name:"小明"},{$push:{hobby:"唱歌"}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find({name:"小明"})
  5. { "_id" : ObjectId("64a66525ff846fd29644e032"), "name" : "小明", "age" : 8, "sex" : "男", "hobby" : [ "draw", "dance", "唱歌" ] }

5.3、小王兴趣爱好增加  吹牛 打篮球

  1. > db.class1.update({name:"小王"},{'$push':{hobby:["吹牛","打篮球"]}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find({name:"小王"})
  5. { "_id" : ObjectId("64a66cb3ff846fd29644e036"), "name" : "小王", "age" : 9, "sex" : "男", "hobby" : [ "draw", "sing", [ "吹牛", "打篮球" ] ] }

5.4、小李增加爱好，跑步和唱歌，但是不要和以前的重复

  1. > db.class1.find({name:"小李"})
  2. { "_id" : ObjectId("64a66e61ff846fd29644e037"), "name" : "小李", "age" : 8, "sex" : "女", "hobby" : [ "draw", "sing" ] }
  3.  
  4. > db.class1.update({name:"小李"},{$addToSet:{hobby:{$each:["跑步","sing"]}}})
  5. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  6.  
  7. > db.class1.find({name:"小李"})
  8. { "_id" : ObjectId("64a66e61ff846fd29644e037"), "name" : "小李", "age" : 8, "sex" : "女", "hobby" : [ "draw", "sing", "跑步" ] }

5.5、该班所有同学年龄加1

  1. > db.class1.update({},{$inc:{age:1}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find()
  5. { "_id" : ObjectId("64a66525ff846fd29644e031"), "name" : "小红", "age" : 9, "sex" : "女", "hobby" : [ "跳舞", "画画" ] }
  6. { "_id" : ObjectId("64a66525ff846fd29644e032"), "name" : "小明", "age" : 8, "sex" : "男", "hobby" : [ "draw", "dance", "唱歌" ] }
  7. { "_id" : ObjectId("64a66cb3ff846fd29644e036"), "name" : "小王", "age" : 9, "sex" : "男", "hobby" : [ "draw", "sing", [ "吹牛", "打篮球" ] ] }
  8. { "_id" : ObjectId("64a66e61ff846fd29644e037"), "name" : "小李", "age" : 8, "sex" : "女", "hobby" : [ "draw", "sing", "跑步" ] }

5.6、 删除小明的sex属性

  1. > db.class1.update({name:"小明"},{'$unset':{sex:1}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find({name:"小明"})
  5. { "_id" : ObjectId("64a66525ff846fd29644e032"), "name" : "小明", "age" : 8, "hobby" : [ "draw", "dance", "唱歌" ] }

5.7、删除小李兴趣中的第一项

  1. > db.class1.update({name:"小李"},{'$pop':{hobby:-1}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
  3.  
  4. > db.class1.find({name:"小李"})
  5. { "_id" : ObjectId("64a66e61ff846fd29644e037"), "name" : "小李", "age" : 8, "sex" : "女", "hobby" : [ "sing", "跑步" ] }

5.8、 将小红兴趣中的画画爱好删除

  1. > db.class1.update({name:"小红"},{'$pull':{hobby:"draw"}})
  2. WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 })
  3.  
  4. > db.class1.find({name:"小红"})
  5. { "_id" : ObjectId("64a66525ff846fd29644e031"), "name" : "小红", "age" : 9, "sex" : "女", "hobby" : [ "跳舞", "画画" ] }

6、增加分数域 并进行下列操作

score:{'chinese':88,'english':78,'math':98}
{name:"张三",sex:"男",score:{chinese:78,english:79,math:98}}
{name:"李四",sex:"男",score:{chinese:98,english:98,math:98}}
{name:"赵四",sex:"男",score:{chinese:58,english:88,math:98}}
{name:"王五",sex:"女",score:{chinese:89,english:74,math:98}}
{name:"钱七",sex:"男",score:{chinese:48,english:78,math:98}}
{name:"孙八",sex:"女",score:{chinese:88,english:78,math:98}}
{name:"侯九",sex:"男",score:{chinese:86,english:75,math:98}}
{name:"熊十",sex:"女",score:{chinese:87,english:48,math:98}}
{name:"熊十",sex:"女",score:{chinese:87,english:48,math:98}}

6.1、按照性别分组统计每组人数

  1. > db.class3.aggregate({$group:{_id:'$sex',num:{$sum:1}}})
  2. { "_id" : "男", "num" : 5 }
  3. { "_id" : "女", "num" : 4 }

6.2、 按照姓名分组，过滤出有重名的同学

  1. > db.class3.aggregate([{$group:{_id:'$name',num:{$sum:1}}},{$match:{num:{$gt:1}}}])
  2. { "_id" : "熊十", "num" : 2 }

6.3、统计每名男生的语文成绩

  1. > db.class3.aggregate([{$match:{sex:"男"}},{$project:{_id:0,name:1,'score.chinese':1}}])
  2. { "name" : "张三", "score" : { "chinese" : 78 } }
  3. { "name" : "李四", "score" : { "chinese" : 98 } }
  4. { "name" : "赵四", "score" : { "chinese" : 58 } }
  5. { "name" : "钱七", "score" : { "chinese" : 48 } }
  6. { "name" : "侯九", "score" : { "chinese" : 86 } }

6.4、将女生按照英语分数降序排列

  1. > db.class3.aggregate([{$match:{sex:"女"}},{$sort:{'score.english':-1}}])
  2. { "_id" : ObjectId("64a6946dff846fd29644e03f"), "name" : "孙八", "sex" : "女", "score" : { "chinese" : 88, "english" : 78, "math" : 98 } }
  3. { "_id" : ObjectId("64a6946dff846fd29644e03d"), "name" : "王五", "sex" : "女", "score" : { "chinese" : 89, "english" : 74, "math" : 98 } }
  4. { "_id" : ObjectId("64a6946dff846fd29644e041"), "name" : "熊十", "sex" : "女", "score" : { "chinese" : 87, "english" : 48, "math" : 98 } }
  5. { "_id" : ObjectId("64a6946dff846fd29644e042"), "name" : "熊十", "sex" : "女", "score" : { "chinese" : 87, "english" : 48, "math" : 98 } }
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