,_id:0}) # 查询所有男性，显示hometown，不显示_id字段
{ "hometown" : "丐帮" }
{ "hometown" : "云南大理" }
{ "hometown" : "少林寺" }
> db.test_table01.find({},{name:1,age:1}) # 查询所有男性，显示_id和name，age字段
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段誉", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语嫣", "age" : 18 }
> db.test_table01.find({},{name:1,age:1,_id:0}) # 查询所有男性，显示name，age字段
{ "name" : "xiaozhao", "age" : 20 }
{ "name" : "乔峰", "age" : 32 }
{ "name" : "段誉", "age" : 22 }
{ "name" : "虚竹", "age" : 28 }
{ "name" : "王语嫣", "age" : 18 }
12.排序
sort() 对查询结果进?排序
语法：
db.集合名称.find().sort({字段:1,...})
参数1为升序排列
参数-1为降序排列
例子:
> db.test_table01.find().sort({age:1}) # 查询所有数据，按age字段升序排列
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语嫣", "hometown" : "燕子坞", "gender" : "female", "age" : 18 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段誉", "hometown" : "云南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
> db.test_table01.find().sort({age:-1}) # 查询所有数据，按age字段降序排列
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段誉", "hometown" : "云南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name&qu