我该如何做SQL等效的“ DISTINCT”？在CouchDB中？ [英] How do I do the SQL equivalent of "DISTINCT" in CouchDB?

问题描述

我在CouchDB中有一堆MP3元数据。我想返回MP3元数据中的所有专辑，但没有重复。

I have a bunch of MP3 metadata in CouchDB. I want to return every album that is in the MP3 metadata, but no duplicates.

一个典型的文档如下：

{
   "_id": "005e16a055ba78589695c583fbcdf7e26064df98",
   "_rev": "2-87aa12c52ee0a406084b09eca6116804",
   "name": "Fifty-Fifty Clown",
   "number": 15,
   "artist": "Cocteau Twins",
   "bitrate": 320,
   "album": "Stars and Topsoil: A Collection (1982-1990)",
   "path": "Cocteau Twins/Stars and Topsoil: A Collection (1982-1990)/15 - Fifty-Fifty Clown.mp3",
   "year": 0,
   "genre": "Shoegaze"
}

推荐答案

我相信您的地图/缩小将类似于：

I believe your map/reduce would look something like:

function map(doc) {
    emit(doc.album, null);
}

function reduce(key, values) {
    return null;
}

请记住使用附加参数 group = true进行查询

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