MongoDB數據庫(二):增刪查改

時間 2019-12-05

原文原文鏈接

MongoDB數據庫的增刪查改正則表達式

1.插入數據

語法：數據庫

db.集合名稱.insert(document)
db.table_name.insert({name:'gj',gender:1})
db.table_name.insert({_id:"20170101",name:'gj',gender:1})

插⼊⽂檔時，若是不指定_id參數，MongoDB會爲⽂檔分配⼀個惟⼀的ObjectId函數

使用insert時若是指定的_id在數據表中已經存在，則插入數據失敗this

例子：code

> db.test_table01.insert({_id:1000001,name:"xiaobing",age:30})          # 向數據庫中插入一條_id爲1000001的數據
WriteResult({ "nInserted" : 1 })

> db.test_table01.insert({_id:1000001,name:"xiaoming",age:40})          # 再次向數據庫中插入一條_id爲1000001的數據，會提示失敗
WriteResult({
        "nInserted" : 0,
        "writeError" : {
                "code" : 11000,
                "errmsg" : "E11000 duplicate key error collection: study_test.test_table01 index: _id_ dup key: { : 1000001.0 }"
        }
})

2.保存數據

語法：排序

db.集合名稱.save(document)

若是⽂檔的_id已經存在則修改文檔，若是⽂檔的_id不存在則添加，相似於Django中的update_or_createip

例子:rem

> db.test_table01.find()
{ "_id" : ObjectId("5c939a4f4c9ce97c5b78a0da"), "name" : "xiaowang", "age" : 10 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaohong", "age" : 20 }
{ "_id" : 1000001, "name" : "xiaobing", "age" : 30 }

> db.test_table01.save({_id:1000001,name:"xiaoming",age:40})            # 向數據庫中保存_id爲1000001的數據，會更新已經的數據
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.test_table01.find()
{ "_id" : ObjectId("5c939a4f4c9ce97c5b78a0da"), "name" : "xiaowang", "age" : 10 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaohong", "age" : 20 }
{ "_id" : 1000001, "name" : "xiaoming", "age" : 40 }

3.簡單查詢

語法：文檔

db.集合名稱.find({條件⽂檔})                # 查詢全部符合條件的文檔
db.集合名稱.findOne({條件⽂檔})             # 根據條件查詢文檔，只返回第⼀個
db.集合名稱.find({條件⽂檔}).pretty()       # 根據條件查詢文檔，並將輸出結果格式化

4.更新

語法：it

db.集合名稱.update(<query> ,<update>,{multi: <boolean>})
參數說明：
    query:查詢條件
    update:更新操做符
    multi:可選，默認是false，表示只更新找到的第⼀條記錄，值爲true表示把滿⾜query條件的⽂檔所有更新

"multi update only works with $ operators":只有替換後的字段前面加上"$"時，才能夠一次性更新多條數據

例子:

> db.userinfo.find().pretty()                                   # userinfo數據庫裏有5條數據
{
        "_id" : ObjectId("5c94f37d25000fc9936a9759"),
        "country" : "china",
        "province" : "sh",
        "userid" : "a"
}
{
        "_id" : ObjectId("5c94f38425000fc9936a975a"),
        "country" : "china",
        "province" : "sh",
        "userid" : "b"
}
{
        "_id" : ObjectId("5c94f38625000fc9936a975b"),
        "country" : "china",
        "province" : "sh",
        "userid" : "c"
}
{
        "_id" : ObjectId("5c94f39325000fc9936a975c"),
        "country" : "china",
        "province" : "bj",
        "userid" : "da"
}
{
        "_id" : ObjectId("5c94f39925000fc9936a975d"),
        "country" : "china",
        "province" : "bj",
        "userid" : "fa"
}
> db.userinfo.update({country:"china"},{set:{country:"zhongguo"}})      # 把country等於china的整條數據替換掉，只替換一條數據
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.userinfo.find()                    # 第一條數據被替換，只有_id字段沒有改變
{ "_id" : ObjectId("5c94f37d25000fc9936a9759"), "set" : { "country" : "zhongguo" } }
{ "_id" : ObjectId("5c94f38425000fc9936a975a"), "country" : "china", "province" : "sh", "userid" : "b" }
{ "_id" : ObjectId("5c94f38625000fc9936a975b"), "country" : "china", "province" : "sh", "userid" : "c" }
{ "_id" : ObjectId("5c94f39325000fc9936a975c"), "country" : "china", "province" : "bj", "userid" : "da" }
{ "_id" : ObjectId("5c94f39925000fc9936a975d"), "country" : "china", "province" : "bj", "userid" : "fa" }

> db.userinfo.update({country:"china"},{$set:{country:"zhongguo"}})     # 把country等於china的字段更新爲country等於zhongguo,只更新一條數據
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.userinfo.find()
{ "_id" : ObjectId("5c94f37d25000fc9936a9759"), "set" : { "country" : "zhongguo" } }
{ "_id" : ObjectId("5c94f38425000fc9936a975a"), "country" : "zhongguo", "province" : "sh", "userid" : "b" }
{ "_id" : ObjectId("5c94f38625000fc9936a975b"), "country" : "china", "province" : "sh", "userid" : "c" }
{ "_id" : ObjectId("5c94f39325000fc9936a975c"), "country" : "china", "province" : "bj", "userid" : "da" }
{ "_id" : ObjectId("5c94f39925000fc9936a975d"), "country" : "china", "province" : "bj", "userid" : "fa" }

> db.userinfo.update({country:"china"},{$set:{country:"zhongguo"}},{multi:true})    # 把country等於china的字段更新爲country等於zhongguo,multi的值爲true,因此更新全部符合條件的數據
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })

> db.userinfo.find()
{ "_id" : ObjectId("5c94f37d25000fc9936a9759"), "set" : { "country" : "zhongguo" } }
{ "_id" : ObjectId("5c94f38425000fc9936a975a"), "country" : "zhongguo", "province" : "sh", "userid" : "b" }
{ "_id" : ObjectId("5c94f38625000fc9936a975b"), "country" : "zhongguo", "province" : "sh", "userid" : "c" }
{ "_id" : ObjectId("5c94f39325000fc9936a975c"), "country" : "zhongguo", "province" : "bj", "userid" : "da" }
{ "_id" : ObjectId("5c94f39925000fc9936a975d"), "country" : "zhongguo", "province" : "bj", "userid" : "fa" }

> db.userinfo.update({country:"zhongguo"},{set:{country:"zh_CN"}},{multi:true})     # multi的值爲true,可是set前沒有加"$",因此這次更新操做沒有更新數據
WriteResult({
        "nMatched" : 0,
        "nUpserted" : 0,
        "nModified" : 0,
        "writeError" : {
                "code" : 9,
                "errmsg" : "multi update only works with $ operators"
        }
})

> db.userinfo.update({country:"zhongguo"},{$set:{country:"zh_CN"}},{multi:true})    # multi的值爲true,set前加了"$",因此把全部文檔的country字段更新爲"zh_CN"
WriteResult({ "nMatched" : 4, "nUpserted" : 0, "nModified" : 4 })

> db.userinfo.find()
{ "_id" : ObjectId("5c94f37d25000fc9936a9759"), "set" : { "country" : "zhongguo" } }
{ "_id" : ObjectId("5c94f38425000fc9936a975a"), "country" : "zh_CN", "province" : "sh", "userid" : "b" }
{ "_id" : ObjectId("5c94f38625000fc9936a975b"), "country" : "zh_CN", "province" : "sh", "userid" : "c" }
{ "_id" : ObjectId("5c94f39325000fc9936a975c"), "country" : "zh_CN", "province" : "bj", "userid" : "da" }
{ "_id" : ObjectId("5c94f39925000fc9936a975d"), "country" : "zh_CN", "province" : "bj", "userid" : "fa" }

5.刪除文檔

語法：

db.集合名稱.remove(<query>,{justOne: <boolean>})
參數說明：
    query:可選，刪除⽂檔的條件
    justOne:可選， 若是設爲true或1， 則只刪除⼀條， 默認false， 表示刪除多條

例子:

> db.test_table01.find()
{ "_id" : ObjectId("5c939a4f4c9ce97c5b78a0da"), "name" : "xiaoqiang", "age" : 10 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : 1000001, "name" : "xiaobei" }
{ "_id" : ObjectId("5c939dd14c9ce97c5b78a0dc"), "name" : "xiaoqiang", "age" : 20 }
{ "_id" : ObjectId("5c939dd44c9ce97c5b78a0dd"), "name" : "xiaoqiang", "age" : 30 }
{ "_id" : ObjectId("5c939dd74c9ce97c5b78a0de"), "name" : "xiaoqiang", "age" : 40 }

> db.test_table01.remove({name:"xiaobei"})          # 刪除全部name爲xiaobei的數據
WriteResult({ "nRemoved" : 1 })     

> db.test_table01.find()
{ "_id" : ObjectId("5c939a4f4c9ce97c5b78a0da"), "name" : "xiaoqiang", "age" : 10 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c939dd14c9ce97c5b78a0dc"), "name" : "xiaoqiang", "age" : 20 }
{ "_id" : ObjectId("5c939dd44c9ce97c5b78a0dd"), "name" : "xiaoqiang", "age" : 30 }
{ "_id" : ObjectId("5c939dd74c9ce97c5b78a0de"), "name" : "xiaoqiang", "age" : 40 }

> db.test_table01.remove({name:"xiaoqiang"},{justOne:true})     # 刪除一條name等於xiaoqiang的數據
WriteResult({ "nRemoved" : 1 })

> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c939dd14c9ce97c5b78a0dc"), "name" : "xiaoqiang", "age" : 20 }
{ "_id" : ObjectId("5c939dd44c9ce97c5b78a0dd"), "name" : "xiaoqiang", "age" : 30 }
{ "_id" : ObjectId("5c939dd74c9ce97c5b78a0de"), "name" : "xiaoqiang", "age" : 40 }

> db.test_table01.remove({name:"xiaoqiang"})         # 刪除全部name等於xiaoqiang的數據,共刪除了3條數據
WriteResult({ "nRemoved" : 3 })

> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }

6.⽐較運算符查詢

MongoDB數據庫中的⽐較運算符有：

=                   等於,默認是等於判斷,沒有運算符
$lt                 ⼩於
$lte                ⼩於等於
$gt                 ⼤於
$gte                ⼤於等於
$ne                 不等於

例子:

> db.test_table01.insert({name:"喬峯",hometown:"丐幫",gender:"male",age:32})            # 向數據表中插入四條數據
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"段譽",hometown:"雲南大理",gender:"male",age:22})
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"虛竹",hometown:"少林寺",gender:"male",age:28})
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"王語嫣",hometown:"燕子塢",gender:"female",age:18})
WriteResult({ "nInserted" : 1 })

> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

> db.test_table01.find({age:{$lt:20}})                  # 查找年齡小於20歲的全部數據
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

> db.test_table01.find({age:{$lte:25}})                 # 查找年齡小於等於25歲的全部數據
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

> db.test_table01.find({age:{$gt:20}})                  # 查找年齡大於20歲的全部數據
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

> db.test_table01.find({age:{$gte:30}})                 # 查找年齡大於等於30歲的全部數據
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }

> db.test_table01.find({age:{$ne:18}})                  # 查找年齡不等於18歲的全部數據
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

7.邏輯運算符查詢

語法：

and         條件與，多個條件共同查詢
or          條件或，符合一個條件與可

例子:

> db.test_table01.find({age:22,gender:"male"})                      # 查找全部年齡爲22，性別爲男的人
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }

> db.test_table01.find({age:{$gt:20},gender:"male"})                # 查找全部年齡大於20，性別爲男的人
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

> db.test_table01.find({$or:[{age:{$gt:20},gender:"male"}]})        # 查找全部年齡大於20或者性別爲男的人
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

> db.test_table01.find({$or:[{age:{$gte:20},gender:"male"}]})       # 查找全部年齡大於等於20或者性別爲男的人
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

8.範圍運算符查詢

語法：

$in             在範圍以內
$nin            不在範圍以內

例子:

> db.test_table01.find({age:{$in:[18,28,38]}})          # 查找年齡爲18或者28或者38的人
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

> db.test_table01.find({age:{$nin:[18,28,38]}})         # 查找年齡不等於18或者28或者38的人
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }

9.正則表達式語句查詢

語法：

//              後接正則表達式進行查詢
$regex          後接正則表達式進行查詢

例子:

> db.test_table01.find({name:{$regex:'^王'}})           # 查找姓王的全部人
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

10.limit和skip

limit()             ⽤於讀取指定數量的⽂檔
skip()              ⽤於跳過指定數量的⽂檔

語法：

db.集合名稱.find({條件⽂檔}).skip(number)               # 按條件查詢，跳過number條數據
db.集合名稱.find({條件⽂檔}).limit(number)              # 按條件查詢，取前number條數據
db.集合名稱.find({條件⽂檔}).limit(10).skip(5)          # 按條件查詢後，取第6到第10條數據
db.集合名稱.find({條件⽂檔}).skip(5).limit(4)           # 按條件查詢後，取第6條到和9條數據

例子:

> db.test_table01.find({gender:"male"})                 # 查詢全部的男性
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

> db.test_table01.find({gender:"male"}).limit(2)        # 查詢全部的男性，取前兩條數據
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }

> db.test_table01.find({gender:"male"}).skip(2)         # 查詢全部的男性，跳過前2條數據
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }

11.投影

語法：

db.集合名稱.find({},{字段名稱:1,...})           # 查詢結果，只選擇必要的字段
參數爲字段與值，值爲1表示顯示，值爲0不顯

對於_id列默認是顯示的，若是不顯示須要明確設置爲0

例子:

> db.test_table01.find({gender:"male"},{name:1,hometown:1})         # 查詢全部的男性，顯示_id，name和hometown
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫" }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理" }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺" }

> db.test_table01.find({gender:"male"},{name:1})                    # 查詢全部男性，顯示name和_id字段
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯" }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽" }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹" }

> db.test_table01.find({gender:"male"},{hometown:1})                # 查詢全部男性，顯示_id和hometown字段
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "hometown" : "丐幫" }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "hometown" : "雲南大理" }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "hometown" : "少林寺" }

> db.test_table01.find({gender:"male"},{hometown:1,_id:0})          # 查詢全部男性，顯示hometown，不顯示_id字段
{ "hometown" : "丐幫" }
{ "hometown" : "雲南大理" }
{ "hometown" : "少林寺" }

> db.test_table01.find({},{name:1,age:1})                           # 查詢全部男性，顯示_id和name，age字段
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "age" : 18 }

> db.test_table01.find({},{name:1,age:1,_id:0})                     # 查詢全部男性，顯示name，age字段
{ "name" : "xiaozhao", "age" : 20 }
{ "name" : "喬峯", "age" : 32 }
{ "name" : "段譽", "age" : 22 }
{ "name" : "虛竹", "age" : 28 } 
{ "name" : "王語嫣", "age" : 18 }

12.排序

sort()          對查詢結果進⾏排序

語法：

db.集合名稱.find().sort({字段:1,...})
    參數1爲升序排列
    參數-1爲降序排列

例子:

> db.test_table01.find().sort({age:1})                              # 查詢全部數據，按age字段升序排列
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }

> db.test_table01.find().sort({age:-1})                             # 查詢全部數據，按age字段降序排列
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }

> db.test_table01.find().sort({name:-1})                            # 查詢全部數據，按name字段降序排列
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }

> db.test_table01.find().sort({hometown:1})                         # 查詢全部數據，按hometown字段升序排列
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段譽", "hometown" : "雲南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王語嫣", "hometown" : "燕子塢", "gender" : "female", "age" : 18 }
> db.test_table01.find({age:{$gt:25}}).sort({age:1})                # 查詢age大於25的全部數據，按age字段升序排列
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虛竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }

13.統計個數

count()                 統計結果集中⽂檔條數

語法：

db.集合名稱.find({查詢條件}).count()
db.集合名稱.count({查詢條件})

例子:

> db.test_table01.find({}).count()                      # 查詢全部數據的數量
5       
> db.test_table01.find({age:{$gt:25}}).count()          # 查詢age大於25的全部數據的總數
2
> db.test_table01.find({gender:"male"}).count()         # 查詢gender等於male的全部數據的總數
3

14.去重

distinct()              對數據進⾏去重

語法：

db.集合名稱.distinct('去重字段',{條件})

例子:

> db.test_table01.distinct("gender")                        # 對gemder字段進行去重
[ "male", "female" ]

> db.test_table01.distinct("gender",{age:{$gt:20}})         # 對age大於20的全部數據的gender字段信息進行去重
[ "male" ]

> db.test_table01.distinct("age")                           # 對全部數據的age字段進行去重
[ 20, 32, 22, 28, 18 ]

> db.test_table01.distinct("name")                          # 對全部數據的name字段進行去重
[ "xiaozhao", "喬峯", "段譽", "虛竹", "王語嫣" ]

15.⾃定義查詢

語法：

使⽤$where後⾯寫⼀個函數， 返回滿⾜條件的數據

例子:

> db.test_table01.find({$where:function(){return this.age > 30}})       # 查詢age大於30的全部數據
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "喬峯", "hometown" : "丐幫", "gender" : "male", "age" : 32 }