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ot; : "王语嫣", "hometown" : "燕子坞", "gender" : "female", "age" : 18 }
> db.test_table01.find().sort({name:-1}) # 查询所有数据，按name字段降序排列
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语嫣", "hometown" : "燕子坞", "gender" : "female", "age" : 18 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段誉", "hometown" : "云南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
> db.test_table01.find().sort({hometown:1}) # 查询所有数据，按hometown字段升序排列
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
{ "_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("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语嫣", "hometown" : "燕子坞", "gender" : "female", "age" : 18 }
> db.test_table01.find({age:{$gt:25}}).sort({age:1}) # 查询age大于25的所有数据，按age字段升序排列
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
13.统计个数
count() 统计结果集中?档条数
语法：
db.集合名称.find({查询条件}).count()
db.集合名称.count({查询条件})
例子:
> db.test_table01.find({}).count() # 查询所有数据的数量
5
> db.test_table01.find({age:{$gt:25}}).count() # 查询age大于25的所有数据的总数
2
> db.test_table01.find({gender:"male"}).count() # 查询gender等于male的所有数据的总数
3
14.去重
distinct() 对数据进?去重
语法：
db.集合名称.distinct('去重字段',{条件})
例子:
> db.test_table01.distinct("gender") # 对gemder字段进行去重
[ "male", "female" ]
> db.test_table01.distinct("gender",{age:{$gt:20}}) # 对age大于20的所有数据的ge
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