MongoDB數據查詢 --MongoDB

1、插入測試數據

use flower

db.goods.insert({'goods_name':'Hyacinth',price:10,num:800})
db.goods.insert({goods_name:'Hyacinth',price:10,num:800})
db.goods.insert({goods_name:'violet',price:20,num:1000})
db.goods.insert({goods_name:'Plum blossom',price:20,num:1000})
db.goods.insert({goods_name:'Datura',price:40,num:700})
db.goods.insert({goods_name:'Rosemary',price:39,num:2000})
db.goods.insert({goods_name:'Rosemary',price:39,num:2000,area:{province:'beijing','city':'beijing'}})
db.goods.insert({goods_name:'Rosemary',price:39,num:2000,area:{province:'Shanghai','city':'Shanghai'}})
db.goods.insert({goods_name:'Chinese rose',price:67,num:3700,area:{province:'Henan','city':'Luoyang'}})
db.goods.insert({goods_name:'Chinese rose',price:32,num:900,area:{province:'Henan','city':'Luoyang'}})
db.goods.insert({goods_name:'Chinese rose',price:32,num:900,area:{province:'Henan','city':'Luoyang'},color:['write','red']})
db.goods.insert({goods_name:'Chinese rose',price:32,num:900,area:{province:'Henan','city':'Luoyang'},color:['red','green']})
db.goods.insert({goods_name:'Chinese rose',price:32,num:900,area:{province:'Henan','city':'Luoyang'},color:['write','red','grees']})

添加數據的方式：普通數據的添加、多維數據的添加、數組數據的添加

2、MongoDB命令行查詢數據

MongoDB命令行查詢數據有以下幾種方式

• 籠統方式查詢
• 條件限制查詢
• 范圍查詢
• 多個查詢條件
• 多維字段的查詢
• 數組條件的限制查詢
• 字段的限制查詢

1）籠統方式查詢：

db.goods.find()

db.goods.find()
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f14b"), "goods_name" : "Hyacinth", "price" : 10, "num" : 800 }
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f14c"), "goods_name" : "Hyacinth", "price" : 10, "num" : 800 }
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f14d"), "goods_name" : "violet", "price" : 20, "num" : 1000 }
……

采用這種方式查詢，會查詢所有數據。

db.goods.findOne()

查詢所有數據中的第一條，並且將數據格式化輸出。

db.goods.findOne()
{
"_id" : ObjectId("5cb5bba28a0ad00bec55f14b"),
"goods_name" : "Hyacinth",
"price" : 10,
"num" : 800
}

2）條件限制查詢

db.goods.find({goods_name:'Hyacinth'})

{ "_id" : ObjectId("5cb5bba28a0ad00bec55f14b"), "goods_name" : "Hyacinth", "price" : 10, "num" : 800 }
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f14c"), "goods_name" : "Hyacinth", "price" : 10, "num" : 800 }

相當於：SELECT *FROM goods WHERE goods_name='Hyacinth'

db.goods.findOne({goods_name:'Hyacinth'})

{
"_id" : ObjectId("5cb5bba28a0ad00bec55f14b"),
"goods_name" : "Hyacinth",
"price" : 10,
"num" : 800
}

該_id字段的內容值是MongoDB本身算法獲得出來的，_id字段對應的值是“全球唯一”的，相當於MySQL表里的主鍵id，是唯一的。id可以自行設置，但是不推薦。
優點：方便MongoDB的數據做升級、遷移

3）范圍查詢

查詢goods表中價格大於10的數據：

db.goods.find({price:{'$gt':10}})

查詢goods表中價格大於等於10的數據：

db.goods.find({price:{'$gte':10}})

查詢goods表中價格小於10的數據：

db.goods.find({price:{'$lt':12}})

查詢goods表中價格小於等於10的數據：

db.goods.find({price:{'$lte':12}})

4）多個查詢條件

例如：要求price大於10，庫存大於800

db.goods.find({price:{'$gt':10},num:{'$gt':800}})

要求price大於10，庫存為900

db.goods.find({price:{'$gt':10},num:900})

5）多維字段的查詢

db.goods.find({'area.province':'Shanghai'})

db.goods.find({'area.city':'Shanghai'})

6）數組條件的限制查詢

查詢“color”中有“red”記錄，滿足一個元素即可：

db.goods.find({color:'red'})

查詢“color”中有“red”並且(AND)有“write”的記錄：

db.goods.find({color:{'$all':['red','write']}})

查詢“price”是10或者(OR)“num”是800

db.goods.find({$or:[{'price':10},{'num':800}]})

7）字段的限制查詢

db.goods.find({price:32},{goods_name:1})

{ "_id" : ObjectId("5cb5bba28a0ad00bec55f154"), "goods_name" : "Chinese rose" }
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f155"), "goods_name" : "Chinese rose" }
{ "_id" : ObjectId("5cb5bba28a0ad00bec55f156"), "goods_name" : "Chinese rose" }
{ "_id" : ObjectId("5cb5bba48a0ad00bec55f157"), "goods_name" : "Chinese rose" }

db.goods.find({price:32},{goods_name:1,_id:0})

{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }

db.goods.find({price:{'$gt':30}},{goods_name:1,_id:0})

{ "goods_name" : "Datura" }
{ "goods_name" : "Rosemary" }
{ "goods_name" : "Rosemary" }
{ "goods_name" : "Rosemary" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }
{ "goods_name" : "Chinese rose" }

db.goods.find({price:{'$gt':30}},{goods_name:1,price:1,_id:0})

{ "goods_name" : "Datura", "price" : 40 }
{ "goods_name" : "Rosemary", "price" : 39 }
{ "goods_name" : "Rosemary", "price" : 39 }
{ "goods_name" : "Rosemary", "price" : 39 }
{ "goods_name" : "Chinese rose", "price" : 67 }
{ "goods_name" : "Chinese rose", "price" : 32 }
{ "goods_name" : "Chinese rose", "price" : 32 }
{ "goods_name" : "Chinese rose", "price" : 32 }
{ "goods_name" : "Chinese rose", "price" : 32 }

說明：_id字段除外，其它字段可以隨意設置0，1。可以設置全部字段都輸出，也設置為全部字段都不輸出。但是，字段中一個是1，另一個是0，這是不可以。