node.js - 以下情况的 mongoDb 查询是什么？

Question

我有一个收藏：

{ "_id" : 1, "item" : "abc", "date" : ISODate("2014-01-01T08:00:00Z"), "price" : 10, "quantity" : 2 }
{ "_id" : 2, "item" : "jkl", "date" : ISODate("2014-02-03T09:00:00Z"), "price" : 20, "quantity" : 1 }
{ "_id" : 3, "item" : "xyz", "date" : ISODate("2014-02-03T09:05:00Z"), "price" : 5, "quantity" : 5 }
{ "_id" : 4, "item" : "abc", "date" : ISODate("2014-02-15T08:00:00Z"), "price" : 10, "quantity" : 10 }
{ "_id" : 5, "item" : "xyz", "date" : ISODate("2014-02-15T09:05:00Z"), "price" : 5, "quantity" : 10 }
{ "_id" : 6, "item" : "xyz", "date" : ISODate("2014-02-15T12:05:10Z"), "price" : 5, "quantity" : 5 }
{ "_id" : 7, "item" : "xyz", "date" : ISODate("2014-02-15T14:12:12Z"), "price" : 5, "quantity" : 10 }
{ "_id" : 7, "item" : "xyz", "date" : ISODate("2014-02-15T17:12:12Z"), "price" : 5, "quantity" : 10 }
{ "_id" : 7, "item" : "pop", "date" : ISODate("2014-02-16T14:12:12Z"), "price" : 5, "quantity" : 10 }
{ "_id" : 7, "item" : "pop", "date" : ISODate("2014-02-10T14:12:12Z"), "price" : 5, "quantity" : 10 }

我想根据给定条件的日期获取最后一个条目......假设：

我想一次使用 $in 运算符获取项目 ["abc","pop"] 的所有最后一个条目。

The result would be : 

{ "_id" : 4, "item" : "abc", "date" : ISODate("2014-02-15T08:00:00Z"), "price" : 10, "quantity" : 10 }
{ "_id" : 7, "item" : "pop", "date" : ISODate("2014-02-16T14:12:12Z"), "price" : 5, "quantity" : 10 }

标签： node.jsmongodb