MongoDB下查询数组的尝试记录

[root@sunrise16 bin]# ./mongo
MongoDB shell version: 2.0.0
connecting to: test

插入一个带有数组元素的文档。
> db.food.insert({"fruit": ["apple", "banana", "peach"]})
> db.food.find()
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }

查询数组元素中包含某个值的文档。
> db.food.find({"fruit": "banana"})
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }

> db.food.find({"fruit": {"$all": ["banana"]}})
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }

查询匹配指定数组的文档。注意要完全相同，数量和顺序都不能有错，否则找不到。

> db.food.find({"fruit": ["banana"]})
> db.food.find({"fruit": ["apple", "banana", "peach"]})
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }
> db.food.find({"fruit": ["banana", "apple", "peach"]})

查询数组元素中包含多个指定值的文档，全部包含，顺序无关。

> db.food.find({"fruit": {"$all": ["banana", "apple", "peach"]}})
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }

查询包含多个值之一的文档。似乎无法实现！

> db.food.find({"fruit":["banna","cherry"]})
> db.food.find({"fruit":{"$all":["banna","cherry"]}})
> db.food.find({"fruit":{"$in":["banna","cherry"]}})

查询指定长度的数组。但不能查询指定长度范围的数组。

> db.food.find({"fruit": {"$size": 3}})
{ "_id" : ObjectId("4ea6a4ef0b12b1d429b4057f"), "fruit" : [ "apple", "banana", "peach" ] }
> db.food.find({"fruit": {"$size": 2}})
> db.food.find({"fruit": {"$size": 4}})
退出。
> exit
bye
[root@sunrise16 bin]#