望野眼_jsp页面模板_百度如何购买关键词_百度账号购买网站

本文所有题目来自头歌学习平台https://www.educoder.net/paths/xe4uogqs
代码是自己写的

数据

var document = [{ "_id": 1, "name": "西西", "sex": "女", "age": 23, "national": "汉族" }, { "_id": 2, "name": "东东", "sex": "男", "age": 20, "national": "苗族" }, { "_id": 3, "name": "北北", "sex": "男", "age": 19, "national": "汉族" }, { "_id": 4, "name": "南南", "sex": "女", "age": 15, "national": "傣族" }
];

要求

把上述数据赋值给变量 document （一条命令），插入到集合 stu1 、stu2；

执行查询命令，查找集合 stu1 中年龄大于等于15岁的女生；

执行查询命令，查找集合 stu1 中苗族人；

执行查询命令，查找集合 stu1 中年龄小于20岁的男生；

执行删除命令，删除集合 stu2 的所有数据。

题目的答案

`var document = [{ "_id": 1, "name": "西西", "sex": "女", "age": 23, "national": "汉族" }, { "_id": 2, "name": "东东", "sex": "男", "age": 20, "national": "苗族" }, { "_id": 3, "name": "北北", "sex": "男", "age": 19, "national": "汉族" }, { "_id": 4, "name": "南南", "sex": "女", "age": 15, "national": "傣族" }
]; 
db.stu1.insertMany(document); 
db.stu2.insertMany(document); 
db.stu1.find({ age: { $gte: 15 }, sex: "女" }); 
db.stu1.find({ national: "苗族" }); 
db.stu1.find({ age: { $lt: 20 }, sex: "男" }); 
db.stu2.deleteMany({});`