数据库结结构_openid：可能多个 [代码][{_id: [代码][代码]"1533796e54ea401fa55be4060f668991"[代码][代码], _openid: [代码][代码]"oaVUp46Ztu4INHIdx-lTIIio555I"[代码][代码], addTime: [代码][代码]"2019-11-01 21:24:09"[代码][代码], validTime: 1573046649027},[代码][代码]{_id: [代码][代码]"92a464912ccf4852bbcf90c060885729"[代码][代码], _openid: [代码][代码]"oaVUp46Ztu4INHIdx-lTIIio555I"[代码][代码], addTime: [代码][代码]"2019-11-01 21:24:20"[代码][代码], validTime: 1573046660592},[代码][代码]{_id: [代码][代码]"ccfc8b521b9c4fd59036995dd7139437"[代码][代码], _openid: [代码][代码]"oaVUp46Ztu4INHIdx-lTIIio555I"[代码][代码], addTime: [代码][代码]"2019-11-01 21:26:18"[代码][代码], validTime: 1573046778242},[代码][代码]{_id: [代码][代码]"afd969472b5447239a92a9444897ae78"[代码][代码], _openid: [代码][代码]"oaVUp46Ztu4INHIdx-lTIIio555I"[代码][代码], addTime: [代码][代码]"2019-11-01 21:27:36"[代码][代码], validTime: 1573046856953},[代码][代码]{_id: [代码][代码]"86d702aa2d0a4216836982b9a1d0ce4b"[代码][代码], _openid: [代码][代码]"oaVUp46Ztu4INHIdx-lTIIio555I"[代码][代码], addTime: [代码][代码]"2019-11-01 21:28:53"[代码][代码], validTime: 1573046933944},[代码][代码]{_id: [代码][代码]"160b8653e7ad43e69bd94ea75a99fd45"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:48"[代码][代码], validTime: 1573047588321},[代码][代码]{_id: [代码][代码]"01f88ec3eb0c46d598fe47954207a570"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:49"[代码][代码], validTime: 1573047589202},[代码][代码]{_id: [代码][代码]"9ef11a0193364cbca5f44c4852aebb50"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:49"[代码][代码], validTime: 1573047589454},[代码][代码]{_id: [代码][代码]"3f62884ee0f844e6b3e1c0d2ff6227a4"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:49"[代码][代码], validTime: 1573047589649},[代码][代码]{_id: [代码][代码]"83359af659ea4683b8ed73e4ad58c5b1"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:49"[代码][代码], validTime: 1573047589823},[代码][代码]{_id: [代码][代码]"c1ea5e825477445facf60fdab37a1b2d"[代码][代码], _openid: [代码][代码]"oaVUp4zrpkGhKsCuF6Sx8AGBJXSg"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:50"[代码][代码], validTime: 1573047590047},[代码][代码]{_id: [代码][代码]"5b0bc911d72a4aa291b102cdfa1eeeb5"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:50"[代码][代码], validTime: 1573047590223},[代码][代码]{_id: [代码][代码]"158d8640e78c43f2ba647de2eafcecaa"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:50"[代码][代码], validTime: 1573047590907},[代码][代码]{_id: [代码][代码]"ba86af1baa7142449cf9e3a955c6b90b"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:39:59"[代码][代码], validTime: 1573047599150},[代码][代码]{_id: [代码][代码]"1141f0644fb746f7af1fe58798698991"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:40:34"[代码][代码], validTime: 1573047634853},[代码][代码]{_id: [代码][代码]"5b1c8adcc274461fa04062a0e6b25b11"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:40:35"[代码][代码], validTime: 1573047635463},[代码][代码]{_id: [代码][代码]"d89467992afb4dc4b8a8125c7a70abc2"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:40:50"[代码][代码], validTime: 1573047650073},[代码][代码]{_id: [代码][代码]"a9dca14680b2401b855881f3543d9d8f"[代码][代码], _openid: [代码][代码]"oaVUp47N8U125EABrHTCXWr8SJDY"[代码][代码], addTime: [代码][代码]"2019-11-01 21:40:55"[代码][代码], validTime: 1573047655545}][代码] 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

ios下播放16:9的视频 首次会横屏 再次进入会竖屏 具体机型:iphone8  系统版本:ios13 [代码]     var[代码] [代码]src = [代码][代码]"https://******.cos.ap-shanghai.myqcloud.com/video/2019-10-14/**.mp4"[代码][代码];[代码][代码]   [代码][代码]var[代码] [代码]poster = [代码][代码]"https://******.cos.ap-shanghai.myqcloud.com/poster/2019-10-14/**.png"[代码][代码];[代码][代码]   [代码][代码]var[代码] [代码]videoContext = wx.createVideoContext([代码][代码]'myvideo'[代码][代码], [代码][代码]this[代码][代码]); [代码] [代码]   [代码][代码]videoContext.requestFullScreen(); //不指定则根据宽高比自动判断[代码][代码]   [代码][代码]this[代码][代码].setData({[代码][代码]     [代码][代码]src: src,[代码][代码]     [代码][代码]poster: poster[代码][代码]   [代码][代码]})[代码]