mongo 中 高级查询之 group

/* 0 */
{
"_id" : ObjectId("553e04180aec5b607765f34b"),
"name" : "aaaaaa",
"date" : ISODate("2015-04-27T09:40:40.345Z"),
"time" : "",
"title" : "11313",
"text" : "121212",
"pinglun" : [
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:16.125Z"),
"text" : "爱的撒旦啊啊",
"id" : "553e04180aec5b607765f34b"
}
]
}

/* 1 */
{
"_id" : ObjectId("553e03870aec5b607765f34a"),
"name" : "aaaaaa",
"date" : ISODate("2015-04-27T09:38:15.409Z"),
"time" : "",
"title" : "111",
"text" : "1111",
"pinglun" : [
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-27T09:38:19.356Z"),
"text" : "11212",
"id" : "553e03870aec5b607765f34a"
},
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:20.410Z"),
"text" : "爱的撒旦啊啊啊实打实",
"id" : "553e03870aec5b607765f34a"
},
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:23.118Z"),
"text" : "爱的撒旦啊啊啊实打实",
"id" : "553e03870aec5b607765f34a"
},
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:24.798Z"),
"text" : "爱的撒旦啊啊啊实打实",
"id" : "553e03870aec5b607765f34a"
},
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:26.295Z"),
"text" : "爱的撒旦啊啊啊实打实",
"id" : "553e03870aec5b607765f34a"
}
]
}

/* 2 */
{
"_id" : ObjectId("553ee2850aec5b607765f34c"),
"name" : "aaaaaa",
"date" : ISODate("2015-04-28T01:29:41.409Z"),
"time" : "",
"title" : "12121",
"text" : "12131313",
"pinglun" : [
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:29:46.070Z"),
"text" : "阿斯达的飒飒",
"id" : "553ee2850aec5b607765f34c"
}
]
}

/* 3 */
{
"_id" : ObjectId("553ee2c80aec5b607765f34e"),
"name" : "aaaaaa",
"date" : ISODate("2015-04-28T01:30:48.431Z"),
"time" : "",
"title" : "1313",
"text" : "12121212",
"pinglun" : []
}

/* 4 */
{
"_id" : ObjectId("553ee2bf0aec5b607765f34d"),
"name" : "aaaaaa",
"date" : ISODate("2015-04-28T01:30:39.398Z"),
"time" : "",
"title" : "暗杀暗杀撒啊",
"text" : "爱上大声的撒",
"pinglun" : [
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:30:43.753Z"),
"text" : "13123131313",
"id" : "553ee2bf0aec5b607765f34d"
},
{
"name" : "aaaaaa",
"day" : ISODate("2015-04-28T01:32:15.446Z"),
"text" : "瓦大厦的萨安师大暗杀大师大",
"id" : "553ee2bf0aec5b607765f34d"
}
]
}

/* 5 */
{
"_id" : ObjectId("559dda00ed63ee0000dc6548"),
"name" : "gjc9620",
"date" : ISODate("2015-07-09T02:18:40.672Z"),
"time" : "",
"title" : "adadadada",
"text" : "adadadasda",
"pinglun" : []
}

/* 6 */
{
"_id" : ObjectId("559dda05ed63ee0000dc6549"),
"name" : "gjc9620",
"date" : ISODate("2015-07-09T02:18:45.119Z"),
"time" : "",
"title" : "adasd",
"text" : "adasdasdas",
"pinglun" : []
}

/* 7 */
{
"_id" : ObjectId("559dda0ced63ee0000dc654a"),
"name" : "gjc9620",
"date" : ISODate("2015-07-09T02:18:52.518Z"),
"time" : "",
"title" : "asdasd",
"text" : "afasdasdasdas",
"pinglun" : []
}

db.posts.group({
"key":{"name":true}, //分组依据
"initial":{"count":0}, //初始值
"reduce":function(doc,prev){

prev.count +=1  //相当于count

},
"condition": {"pinglun": {"$gte": {"$size":1}}}  //过滤条件
})

/* 0 */
{
"0" : {
"name" : "aaaaaa",
"count" : 4
},
"1" : {
"name" : "gjc9620",
"count" : 1
}
}