{"id":207799,"date":"2025-07-08T10:47:31","date_gmt":"2025-07-08T02:47:31","guid":{"rendered":"https:\/\/server.hk\/cnblog\/207799\/"},"modified":"2025-07-08T10:47:31","modified_gmt":"2025-07-08T02:47:31","slug":"%e5%a6%82%e4%bd%95%e5%9c%a8-golang-%e4%b8%ad%e4%bd%bf%e7%94%a8-facet-%e5%92%8c-mgo-%e5%ba%93%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/207799\/","title":{"rendered":"\u5982\u4f55\u5728 golang \u4e2d\u4f7f\u7528 $facet \u548c mgo \u5e93\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u5982\u4f55\u5728 golang \u4e2d\u4f7f\u7528 $facet \u548c mgo \u5e93\uff1f<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-25 18:15:33<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u4eca\u5929\u7ed9\u5927\u5bb6\u5e26\u6765\u4e86\u300a\u5982\u4f55\u5728 golang \u4e2d\u4f7f\u7528 $facet \u548c mgo \u5e93\uff1f\u300b<\/span>\uff0c\u5176\u4e2d\u6d89\u53ca\u5230\u7684\u77e5\u8bc6\u70b9\u5305\u62ec<\/span>\u7b49\u7b49\uff0c\u65e0\u8bba\u4f60\u662f\u5c0f\u767d\u8fd8\u662f\u8001\u624b\uff0c\u90fd\u9002\u5408\u770b\u4e00\u770b\u54e6~\u6709\u597d\u7684\u5efa\u8bae\u4e5f\u6b22\u8fce\u5927\u5bb6\u5728\u8bc4\u8bba\u7559\u8a00\uff0c\u82e5\u662f\u770b\u5b8c\u6709\u6240\u6536\u83b7\uff0c\u4e5f\u5e0c\u671b\u5927\u5bb6\u80fd\u591a\u591a\u70b9\u8d5e\u652f\u6301\u5440\uff01\u4e00\u8d77\u52a0\u6cb9\u5b66\u4e60~<\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u6211\u5f00\u59cb\u5b66\u4e60 mongodb \u7684\u6027\u80fd\u6539\u8fdb\u3002\u6211\u6709\u4e00\u4e2a\u57fa\u4e8e\u95ee\u9898\u7684\u805a\u5408\u51fd\u6570\u3002 \u6211\u521b\u5efa\u4e86\u4e00\u4e2a\u57fa\u672c\u6d4b\u8bd5\u96c6\u5408\uff0c\u5305\u542b 3 \u4e2a\u5b57\u6bb5\u4ea7\u54c1\u3001\u989c\u8272\u548c\u5e74\u4efd\uff1a<\/p>\n

{\n    \"product\" : \"car\",\n    \"colour\" : \"red\",\n    \"year\" : \"2019\"\n}\n{\n    \"product\" : \"car\",\n    \"colour\" : \"black\",\n    \"year\" : \"2018\"\n}\n{\n    \"product\" : \"bike\",\n    \"colour\" : \"blue\",\n    \"year\" : \"2014\"\n}\n{\n    \"product\" : \"train\",\n    \"colour\" : \"black\",\n    \"year\" : \"2019\"\n}\n{\n    \"product\" : \"ship\",\n    \"colour\" : \"red\",\n    \"year\" : \"2018\"\n}\n{\n    \"product\" : \"car\",\n    \"colour\" : \"red\",\n    \"year\" : \"2016\"\n}\n{\n    \"product\" : \"car\",\n    \"colour\" : \"blue\",\n    \"year\" : \"2015\"\n}\n{\n    \"product\" : \"bike\",\n    \"colour\" : \"white\",\n    \"year\" : \"2014\"\n}\n{\n    \"product\" : \"train\",\n    \"colour\" : \"red\",\n    \"year\" : \"2016\"\n}\n{\n    \"product\" : \"ship\",\n    \"colour\" : \"red\",\n    \"year\" : \"2015\"\n}<\/pre>\n
\u7531\u4e8e\u6027\u80fd\u95ee\u9898\uff0c\u6211\u5e0c\u671b\u4f7f\u7528facet\u8fdb\u884c\u5355\u4e2a\u805a\u5408\u9636\u6bb5\uff1a<\/p>\n
db.getCollection('test').aggregate([\n    {\n        \"$match\":{\n            \"colour\":\"red\"\n        }\n    },\n    {\n        \"$facet\": {\n            \"cntOfReds\":[\n                {\"$group\":{\"_id\": \"$product\", \"count\": {\"$sum\": 1}}}\n            ],\n            \"cntOfRedsIn2015\":[\n                {\"$match\" :{\"year\": \"2015\"}},\n                {\"$group\": {\"_id\": \"$year\", \"count\": {\"$sum\": 1}}}\n            ]\n    }   }\n\n    ])<\/pre>\n
\u6211\u4eec\u5982\u4f55\u4f7f\u7528 mgo.v2 \u5728 golang \u4e0a\u5b9e\u73b0\u76f8\u540c\u7684\u67e5\u8be2\u5e76\u5c06\u7ed3\u679c\u8bbe\u7f6e\u4e3a\u7ed3\u6784\u4f53\uff1f<\/p>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
\u4f7f\u7528 mgo\uff0c\u60a8\u5fc5\u987b\u5c06\u6587\u6863\u6570\u7ec4\u4f20\u9012\u7ed9 pipe<\/code>\uff1a<\/p>\n
p:=collection.pipe([]bson.m{\n  {\"$match\": bson.m{\"colour\":\"red\"}},\n  {\"$facet\": bson.m{ \"cntofreds\":[]bson.m{{\"$group\":{\"_id\": \"$product\", \"count\": bson.m{\"$sum\":1}}}}},\n  \"cntofredsin2015\": ...<\/pre>\n
\u7136\u540e\uff0c\u8fd0\u884c\u7ba1\u9053\u5e76\u83b7\u53d6\u7ed3\u679c\uff1a<\/p>\n
p.All(&results)<\/pre>\n
\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300a\u5982\u4f55\u5728 golang \u4e2d\u4f7f\u7528 $facet \u548c mgo \u5e93\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u516c\u4f17\u53f7\u5427\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-207799","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207799","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=207799"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207799\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=207799"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=207799"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=207799"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}