[query whereKey:@"createAt" greaterThan:time];

想获取createAt大于time的记录。增加了这样的条件，结果查询不到数据。打开日志，如下：

2016-08-17 09:59:03.131

------ BEGIN LeanCloud REST Request ------
path: /1.1/classes/T_Activity
curl: curl -i -k --compressed -X GET -G -H 'User-Agent: AVOS Cloud iOS-v3.2.12 SDK' -H 'Content-Type: application/json; charset=utf-8' -H 'Accept: application/json' -H 'X-LC-Id:这里被我屏蔽了' -H 'X-LC-Sign: 这里被我屏蔽了' -H 'X-LC-Prod: 1' --data-urlencode 'where={"createAt":{"$gt":{"_type":"Date","iso":"2016-08-15T16:38:50.021Z"}}}' "https://api.leancloud.cn/1.1/classes/TActivity"
------ END -------------------------------

2016-08-17 09:59:03.422 这里被我屏蔽了[6772:3110758] [DEBUG] _56-[AVPaasClient performCurl:saveResult:block:retryTimes:]block_invoke [Line 597]

------ BEGIN LeanCloud REST Response ------
path: /1.1/classes/T_Activity
cost: 0.292s
response: {"results":[]}
------ END --------------------------------

数据库里是有记录的

 {

"ACL": {
"*": {
"read": true
}
},
"title": "测试",
"objectId": "57b3c0a1a34131006467234d",
"createdAt": "2016-08-17T01:40:49.747Z",
"updatedAt": "2016-08-17T01:53:38.317Z"
}