小编Swa*_*ika的帖子

我有一些存储在S3存储桶中的json文件,其中每个文件都有多个结构相同的元素.例如,

[{"eventId":"1","eventName":"INSERT","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"New item!","Id":101}},{"eventId":"2","eventName":"MODIFY","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}},{"eventId":"3","eventName":"REMOVE","eventVersion":"1.0","eventSource":"aws:dynamodb","awsRegion":"us-west-2","image":{"Message":"This item has changed","Id":101}}]

我想在Athena中创建一个与上述数据相对应的表格.

我写的用于创建表的查询:

CREATE EXTERNAL TABLE IF NOT EXISTS sampledb.elb_logs2 (
  `eventId` string,
  `eventName` string,
  `eventVersion` string,
  `eventSource` string,
  `awsRegion` string,
  `image` map<string,string> 
)
ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe'
WITH SERDEPROPERTIES (
  'serialization.format' = '1',
  'field.delim' = ' '
) LOCATION 's3://<bucketname>/';

但如果我按如下方式进行SELECT查询,

SELECT * FROM sampledb.elb_logs4;

我得到以下结果:

1   {"eventid":"1","eventversion":"1.0","image":{"id":"101","message":"New item!"},"eventsource":"aws:dynamodb","eventname":"INSERT","awsregion":"us-west-2"}   {"eventid":"2","eventversion":"1.0","image":{"id":"101","message":"This item has changed"},"eventsource":"aws:dynamodb","eventname":"MODIFY","awsregion":"us-west-2"}   {"eventid":"3","eventversion":"1.0","image":{"id":"101","message":"This item has changed"},"eventsource":"aws:dynamodb","eventname":"REMOVE","awsregion":"us-west-2"}   

json文件的全部内容在此处作为一个条目被选中.

如何将json文件的每个元素作为一个条目读取？

编辑:如何读取图像的每个子列,即地图的每个元素？

谢谢.

在我的步骤函数中，我想执行 Athena 查询。我能够定义一个步骤并成功执行查询。但是，我想传递一些参数作为输入并在查询字符串中使用它们。例如。

假设我的查询字符串是：

select * from <Data Source>.<database>.<tablename> where partition_0 = '2021';

我希望能够将年份作为输入 json 传递给步骤函数，例如：

{
"YYYY": 2021
}

是否可以在查询字符串中插入输入“YYYY”？如果是这样，怎么办？

步骤函数配置示例：

{
  "Comment": "Start athena exececution",
  "StartAt": "athena",
  "States": {
    "athena": {
      "Type": "Task",
      "InputPath": "$",
      "Resource": "arn:aws:states:::athena:startQueryExecution.sync",
      "Parameters": {
        "QueryString": "select * from mycatalog.mydatabase.mytable where partition_0 = '2021'",
        "WorkGroup": "primary",
        "ResultConfiguration": {
          "OutputLocation": "s3://mys3bucket"
        }
      },
      "Next": "Pass"
    },
    "Pass": {
      "Comment": "A Pass state passes its input to its output, without performing work. Pass states are useful …

我有一个A大小为nRows x nCols 的矩阵.

我有一个nx2矩阵B,其中包含矩阵的索引A.我想获得A给出的指数的值B.

比方说,

B = [1, 2;
     2, 3;
     3, 4]

A(1,2) = 1
A(2,3) = 2
A(3,4) = 1

我想知道任何给出以下的Matlab命令,给定A和B(我不想使用循环):

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