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mongodb的分頁查詢

下面這個是我的測試資料

> db.test.find().sort({"age":1});
{ "_id" : ObjectId("58623df3d13eafd014b937ab"), "name" : "aa", "age" : 20 }
{ "_id" : ObjectId("58623e3bd13eafd014b937ac"), "name" : "bb", "age" : 21 }
{ "_id" : ObjectId("58623e43d13eafd014b937ad"), "name" : "cc", "age" : 22 }
{ "_id" : ObjectId("58623e4bd13eafd014b937ae"), "name" : "dd", "age" : 23 }
{ "_id" : ObjectId("58623e53d13eafd014b937af"), "name" : "ee", "age" : 24 }
{ "_id" : ObjectId("58623e5bd13eafd014b937b0"), "name" : "ff", "age" : 25 }
{ "_id" : ObjectId("58623e67d13eafd014b937b1"), "name" : "gg", "age" : 26 }
{ "_id" : ObjectId("58623e6ed13eafd014b937b2"), "name" : "hh", "age" : 27 }
{ "_id" : ObjectId("58623e78d13eafd014b937b3"), "name" : "ii", "age" : 28 }
{ "_id" : ObjectId("58623e7fd13eafd014b937b4"), "name" : "jj", "age" : 29 }
{ "_id" : ObjectId("58623e87d13eafd014b937b5"), "name" : "kk", "age" : 30 }

第一種方法:

> db.test.find().sort({"age":1}).limit(2);
{ "_id" : ObjectId("58623df3d13eafd014b937ab"), "name" : "aa", "age" : 20 }
{ "_id" : ObjectId("58623e3bd13eafd014b937ac"), "name" : "bb", "age" : 21 }
> db.test.find().sort({"age":1}).skip(2).limit(2);
{ "_id" : ObjectId("58623e43d13eafd014b937ad"), "name" : "cc", "age" : 22 }
{ "_id" : ObjectId("58623e4bd13eafd014b937ae"), "name" : "dd", "age" : 23 }

第二種方法:

查詢第一頁的資料:

> db.test.find().sort({"age":1}).limit(2);
{ "_id" : ObjectId("58623df3d13eafd014b937ab"), "name" : "aa", "age" : 20 }
{ "_id" : ObjectId("58623e3bd13eafd014b937ac"), "name" : "bb", "age" : 21 }

查詢第二頁的資料:

> var p1 = db.test.find().sort({"age":1}).limit(2);
> var latest=null;
> while(p1.hasNext()){
... latest=p1.next();
... }
{ "_id" : ObjectId("58623e3bd13eafd014b937ac"), "name" : "bb", "age" : 21 }


> db.test.find({"age":{"$gt":latest.age}}).sort({"age":1}).limit(2);
{ "_id" : ObjectId("58623e43d13eafd014b937ad"), "name" : "cc", "age" : 22 }
{ "_id" : ObjectId("58623e4bd13eafd014b937ae"), "name" : "dd", "age" : 23 }

總結來說,如果資料量不是很大的話,可以使用第一種方法,畢竟比較簡單,如果資料量比較大的話,使用第二種方法比較好,因為這樣就可以不用到skip()這個函式,skip跳過太多的記錄,效率有點低