如何从索引查询两个值？ Appsync查询DynamoDB

Question

我的解析器模板

{
   "version" : "2017-02-28",
    "operation" : "Query",
    "query" : {
        "expression" : "receiverusername = :receiverusername and createdat > :createdat",
        "expressionValues" : {
            ":receiverusername" : $util.dynamodb.toDynamoDBJson($context.identity.username),
            ":createdat" : $util.dynamodb.toDynamoDBJson($ctx.args.input.lastDate),
        }
    },
    "index" : "receiverusername-createdat-index",
}

我正在尝试查询日期和用户名，但是我一直在收到此错误，

{
  "data": {
    "listMyMessages": null
  },
  "errors": [
    {
      "path": [
        "listMyMessages"
      ],
      "data": null,
      "errorType": "DynamoDB:DynamoDbException",
      "errorInfo": null,
      "locations": [
        {
          "line": 2,
          "column": 3,
          "sourceName": null
        }
      ],
      "message": "One or more parameter values were invalid: Condition parameter type does not match schema type (Service: DynamoDb, Status Code: 400, Request ID: 7I18ODEK46H52NMBSF99OTNSQ7VV4KQNSO5AEMVJF66Q9ASUAAJG)"
    }
  ]

该如何查询此问题？

我试图从文档中学习，但没有任何线索！

Answer 1

对于DynamoDB，不可能同时查询2个值，因为每个GSI都会创建一个具有不同索引的重复表。我能想到的一个很好的解决方案是并行查询索引并返回其交流。

Answer 2

我只是这样做了，它起作用了。
是的，我没有触摸或调查原因。

{
    "version" : "2017-02-28",
    "operation" : "Query",
    "index" : "receiverusername-createdat-index",
    "query" : {
        ## Provide a query expression. **
        "expression": "receiverusername = :receiverusername and createdat > :createdat",
        "expressionValues" : {
            ":receiverusername" : {
                "S" : "${context.identity.username}"
            },
            ":createdat": {
                "S": "${ctx.args.lastDate}"
            }
        }
    }
}

我没有使用排序键，而只是索引键