数据库结结构_openid：可能多个
[{_id: "1533796e54ea401fa55be4060f668991", _openid: "oaVUp46Ztu4INHIdx-lTIIio555I", addTime: "2019-11-01 21:24:09", validTime: 1573046649027},{_id: "92a464912ccf4852bbcf90c060885729", _openid: "oaVUp46Ztu4INHIdx-lTIIio555I", addTime: "2019-11-01 21:24:20", validTime: 1573046660592},{_id: "ccfc8b521b9c4fd59036995dd7139437", _openid: "oaVUp46Ztu4INHIdx-lTIIio555I", addTime: "2019-11-01 21:26:18", validTime: 1573046778242},{_id: "afd969472b5447239a92a9444897ae78", _openid: "oaVUp46Ztu4INHIdx-lTIIio555I", addTime: "2019-11-01 21:27:36", validTime: 1573046856953},{_id: "86d702aa2d0a4216836982b9a1d0ce4b", _openid: "oaVUp46Ztu4INHIdx-lTIIio555I", addTime: "2019-11-01 21:28:53", validTime: 1573046933944},{_id: "160b8653e7ad43e69bd94ea75a99fd45", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:48", validTime: 1573047588321},{_id: "01f88ec3eb0c46d598fe47954207a570", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:49", validTime: 1573047589202},{_id: "9ef11a0193364cbca5f44c4852aebb50", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:49", validTime: 1573047589454},{_id: "3f62884ee0f844e6b3e1c0d2ff6227a4", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:49", validTime: 1573047589649},{_id: "83359af659ea4683b8ed73e4ad58c5b1", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:49", validTime: 1573047589823},{_id: "c1ea5e825477445facf60fdab37a1b2d", _openid: "oaVUp4zrpkGhKsCuF6Sx8AGBJXSg", addTime: "2019-11-01 21:39:50", validTime: 1573047590047},{_id: "5b0bc911d72a4aa291b102cdfa1eeeb5", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:39:50", validTime: 1573047590223},{_id: "158d8640e78c43f2ba647de2eafcecaa", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:39:50", validTime: 1573047590907},{_id: "ba86af1baa7142449cf9e3a955c6b90b", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:39:59", validTime: 1573047599150},{_id: "1141f0644fb746f7af1fe58798698991", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:40:34", validTime: 1573047634853},{_id: "5b1c8adcc274461fa04062a0e6b25b11", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:40:35", validTime: 1573047635463},{_id: "d89467992afb4dc4b8a8125c7a70abc2", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:40:50", validTime: 1573047650073},{_id: "a9dca14680b2401b855881f3543d9d8f", _openid: "oaVUp47N8U125EABrHTCXWr8SJDY", addTime: "2019-11-01 21:40:55", validTime: 1573047655545}] |
要求： 1.取一组数据 里面的_openid不能重复 2.并且validTime是相同_openid里面最大的 云函数搜索条件该如何编写？？谢谢
https://developers.weixin.qq.com/miniprogram/dev/wxcloud/reference-client-api/database/aggregation/operators/first.html
参考这个，应该可以满足你的需求
类似如下写法：
const $ = db.command.aggregatedb.collection('collection_name').aggregate().sort({_openid: 1, validTime: -1}).group({_id:"$_openid",__id: $.first('$_id'),validTime: $.first('$validTime'),addTime: $.first('$addTime')}).end()注意加索引
你这个集合设计得有问题啊
插入前不能判断_openid是否存在吗
存在就更新，不存在就新增，不就没有现在这麻烦事了？？
db.collection('xxx').aggregate()
.group({
_openid:'$_openid',
validTime: $.max('$validTime')
})
.end()
db.collection('xxx').aggregate()
.match({
_openid:'xxxxxxxxx'
})
.group({
_openid:'$_openid',
validTime: $.max('$validTime')
})
.end()
拜托大神们！！！
首先根据vaildTime从大到小排序，然后用Set来去重