{"id":184842,"date":"2023-07-13T07:13:38","date_gmt":"2023-07-12T23:13:38","guid":{"rendered":"http:\/\/www.idc.net\/help\/184842\/"},"modified":"2023-07-13T07:13:38","modified_gmt":"2023-07-12T23:13:38","slug":"%e5%90%8e%e6%b5%aa%e4%ba%91%e5%b0%8f%e7%a8%8b%e5%ba%8f%e6%95%99%e7%a8%8b%ef%bc%9asdk%e6%95%b0%e6%8d%ae%e5%ba%93-command%c2%b7%e8%81%9a%e5%90%88%e6%93%8d%e4%bd%9c%e7%ac%a6%c2%b7%e5%8f%98%e9%87%8f","status":"publish","type":"post","link":"https:\/\/idc.net\/help\/184842\/","title":{"rendered":"\u540e\u6d6a\u4e91\u5c0f\u7a0b\u5e8f\u6559\u7a0b\uff1aSDK\u6570\u636e\u5e93 Command\u00b7\u805a\u5408\u64cd\u4f5c\u7b26\u00b7\u53d8\u91cf\u64cd\u4f5c\u7b26"},"content":{"rendered":"

AggregateCommand.let(value: any): Object<\/h2>\n

\n \u652f\u6301\u7aef\uff1a\u5c0f\u7a0b\u5e8f 2.7.4, \u4e91\u51fd\u6570 0.8.1, Web\n<\/p><\/blockquote>\n

\u805a\u5408\u64cd\u4f5c\u7b26\u3002\u81ea\u5b9a\u4e49\u53d8\u91cf\uff0c\u5e76\u4e14\u5728\u6307\u5b9a\u8868\u8fbe\u5f0f\u4e2d\u4f7f\u7528\uff0c\u8fd4\u56de\u7684\u7ed3\u679c\u662f\u8868\u8fbe\u5f0f\u7684\u7ed3\u679c\u3002<\/p>\n

\u53c2\u6570<\/h2>\n

value: any<\/h3>\n

\u8fd4\u56de\u503c<\/h2>\n

Object<\/h3>\n

API \u8bf4\u660e<\/h2>\n

let \u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

db.command.aggregate.let({\n  vars: {\n    <\u53d8\u91cf1>: <\u53d8\u91cf\u8868\u8fbe\u5f0f>,\n    <\u53d8\u91cf2>: <\u53d8\u91cf\u8868\u8fbe\u5f0f>,\n    ...\n  },\n  in: <\u7ed3\u679c\u8868\u8fbe\u5f0f>\n})\n<\/code><\/pre>\n
vars \u4e2d\u53ef\u4ee5\u5b9a\u4e49\u591a\u4e2a\u53d8\u91cf\uff0c\u53d8\u91cf\u7684\u503c\u7531 \u53d8\u91cf\u8868\u8fbe\u5f0f \u8ba1\u7b97\u800c\u6765\uff0c\u5e76\u4e14\u88ab\u5b9a\u4e49\u7684\u53d8\u91cf\u53ea\u6709\u5728 in \u4e2d\u7684 \u7ed3\u679c\u8868\u8fbe\u5f0f \u624d\u53ef\u4ee5\u8bbf\u95ee\u3002<\/p>\n
\u5728 in \u7684\u7ed3\u679c\u8868\u8fbe\u5f0f\u4e2d\u8bbf\u95ee\u81ea\u5b9a\u4e49\u53d8\u91cf\u65f6\u5019\uff0c\u8bf7\u5728\u53d8\u91cf\u540d\u524d\u52a0\u4e0a\u53cc\u7f8e\u5143\u7b26\u53f7( $$ )\u5e76\u7528\u5f15\u53f7\u62ec\u8d77\u6765\u3002<\/p>\n
\u793a\u4f8b\u4ee3\u7801<\/h2>\n
\u5047\u8bbe\u4ee3\u8868\u5546\u54c1\u7684\u96c6\u5408 goods \u7684\u8bb0\u5f55\u5982\u4e0b\uff1aprice \u4ee3\u8868\u5546\u54c1\u4ef7\u683c\uff0cdiscount \u4ee3\u8868\u5546\u54c1\u6298\u6263\u7387\uff0ccost \u4ee3\u8868\u5546\u54c1\u6210\u672c<\/p>\n
{ \"cost\": -10, \"discount\": 0.95, \"price\": 100 }\n{ \"cost\": -15, \"discount\": 0.98, \"price\": 1 }\n{ \"cost\": -10, \"discount\": 1, \"price\": 10 }\n<\/code><\/pre>\n
\u501f\u52a9 let \u53ef\u4ee5\u5b9a\u4e49\u5e76\u8ba1\u7b97\u6bcf\u4ef6\u5546\u54c1\u5b9e\u9645\u7684\u9500\u552e\u4ef7\u683c\uff0c\u5e76\u5c06\u5176\u8d4b\u503c\u7ed9\u81ea\u5b9a\u4e49\u53d8\u91cf priceTotal\u3002\u6700\u540e\u518d\u5c06 priceTotal \u4e0e cost \u8fdb\u884c\u53d6\u548c( sum )\u8fd0\u7b97\uff0c\u5f97\u5230\u6bcf\u4ef6\u5546\u54c1\u7684\u5229\u6da6\u3002<\/p>\n
\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
const $ = db.command.aggregate\ndb\n  .collection('goods')\n  .aggregate()\n  .project({\n    profit: $.let({\n      vars: {\n        priceTotal: $.multiply(['$price', '$discount'])\n      },\n      in: $.sum(['$$priceTotal', '$cost'])\n    })\n  })\n  .end()\n<\/code><\/pre>\n
\u8fd4\u56de\u7684\u6570\u636e\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n
{ \"profit\": 85 }\n{ \"profit\": -14.02 }\n{ \"profit\": 0 }<\/code><\/pre>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
AggregateCommand.let(value: any): Object \u652f\u6301\u7aef\uff1a\u5c0f\u7a0b\u5e8f 2.7.4, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[182398],"tags":[],"class_list":["post-184842","post","type-post","status-publish","format-standard","hentry","category-mini-program"],"_links":{"self":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/184842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/comments?post=184842"}],"version-history":[{"count":0,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/184842\/revisions"}],"wp:attachment":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/media?parent=184842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/categories?post=184842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/tags?post=184842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}