# MongoDB 查詢
## 描述
本教程我們將向大家介紹如何在MongoDB集合中獲取數據。
**我們使用的數據庫名稱為"myinfo" 我們的集合名稱為"userdetails",以下為我們插入的數據:**
```
> db.userdetails.insert({"user_id" : "user1","password" :"1a2b3c" ,"date_of_join" : "16/10/2010" ,"education" :"M.C.A."
, "profession" : "CONSULTANT","interest" : "MUSIC","community_name" :["MODERN MUSIC", "CLASSICAL MUSIC","WESTERN
MUSIC"],"community_moder_id" : ["MR. Alex","MR. Dang","MR Haris"],"community_members" :
[700,200,1500],"friends_id" : ["kumar","harry","anand"],"ban_friends_id" :["Amir","Raja","mont"]});
```
```
> db.userdetails.insert({"user_id" : "user2","password" :"11aa1a" ,"date_of_join" : "17/10/2009" ,"education"
:"M.B.A." , "profession" : "MARKETING","interest" : "MUSIC","community_name" :["MODERN MUSIC", "CLASSICAL
MUSIC","WESTERN MUSIC"],"community_moder_id" : ["MR. Roy","MR. Das","MR Doglus"],"community_members" :
[500,300,1400],"friends_id" : ["pal","viki","john"],"ban_friends_id" :["jalan","monoj","evan"]});
```
```
> db.userdetails.insert({"user_id" : "user3","password" :"b1c1d1" ,"date_of_join" : "16/10/2010" ,"education"
:"M.C.A." , "profession" : "IT COR.","interest" : "ART","community_name" :["MODERN ART", "CLASSICAL ART","WESTERN
ART"],"community_moder_id" : ["MR. Rifel","MR. Sarma","MR Bhatia"],"community_members" :
[5000,2000,1500],"friends_id" : ["philip","anant","alan"],"ban_friends_id" :["Amir","Raja","mont"]});
```
```
> db.userdetails.insert({"user_id" : "user4","password" :"abczyx" ,"date_of_join" : "17/8/2009" ,"education"
:"M.B.B.S." , "profession" : "DOCTOR","interest" : "SPORTS","community_name" :["ATHELATIC", "GAMES FAN
GYES","FAVOURIT GAMES"],"community_moder_id" : ["MR. Paul","MR. Das","MR Doglus"],"community_members" :
[2500,2200,3500],"friends_id" : ["vinod","viki","john"],"ban_friends_id" :["jalan","monoj","evan"]});
```
## 從集合中獲取數據
如果你想在集合中讀取所有的的數據,可以執行以下命令
```
> db.userdetails.find();
```
類似于如下SQL查詢語句:
```
Select * from userdetails;
```
輸出數據如下所示:

## 通過指定條件讀取數據
如果我們想在集合"userdetails"中讀取"education"為"M.C.A." 的數據,我們可以執行以下命令:
```
> db.userdetails.find({"education":"M.C.A."})
```
類似如下SQL查詢語句:
```
Select * from userdetails where education="M.C.A.";
```
輸出結果如下所示:

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