我将带有您提供的内容的示例csv文件上传到S3。然后我在上面跑了一个胶履带。这是我最终得到的表模式：

CREATE EXTERNAL TABLE `question_58765672`(
  `timestamp` bigint,`project_id` bigint,`campaign_id` bigint,`experiment_id` bigint,`variation_id` bigint,`layer_holdback` boolean,`audience_names` array<string>,`end_user_id` string,`uuid` string,`session_id` string,`snippet_revision` bigint,`user_ip` string,`user_agent` string,`user_engine` string,`user_engine_version` string,`referer` string,`global_holdback` boolean,`event_type` string,`event_name` bigint,`uf` string,`active_views` array<string>,`event_features` array<string>,`event_metrics` array<string>,`event_uuid` string)
ROW FORMAT DELIMITED 
  FIELDS TERMINATED BY '\t' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.mapred.TextInputFormat' 
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  's3://__S3_PATH_IN_MY_BUCKET__/'
TBLPROPERTIES (
  'CrawlerSchemaDeserializerVersion'='1.0','CrawlerSchemaSerializerVersion'='1.0','UPDATED_BY_CRAWLER'='some-crawler','areColumnsQuoted'='false','averageRecordSize'='553','classification'='csv','columnsOrdered'='true','compressionType'='none','delimiter'='\t','objectCount'='1','recordCount'='2','sizeKey'='1109','skip.header.line.count'='1','typeOfData'='file')

您可以看到它将列uf标识为字符串，对此我并不感到意外。为了取消嵌套此列，我必须手动将其强制转换为正确的类型ARRAY(JSON)：

SELECT
    "timestamp",_unnested_column
FROM
    "stackoverflow"."question_58765672",UNNEST( CAST(json_parse(uf) AS ARRAY(JSON)) ) AS t(_unnested_column)

结果：

    timestamp   _unnested_column
1   1570326511  {"name":"","type":"browserId","value":"unknown"}
2   1570326511  {"name":"","type":"device","value":"mobile"}
3   1570326511  {"name":"","type":"device_type","value":"phone"}
4   1570326511  {"name":"","type":"referrer","value":"https://www.google.co.uk/"}
5   1570326511  {"name":"","type":"source_type","value":"campaign"}
6   1570326511  {"name":"","type":"currentTimestamp","value":"-1631518596"}
7   1570326511  {"name":"","type":"offset","value":"-60"}

然后，我想到了创建一个athena views的地方，其中列uf会被正确地投射：

CREATE OR REPLACE VIEW question_58765672_v1_json AS
SELECT
    CAST(json_parse(uf) AS ARRAY(JSON)) as uf
    -- ALL other columns from your table
FROM 
    "stackoverflow"."question_58765672"

但是，出现以下错误：

  

列uf的列类型无效：不受支持的配置单元类型：json

我的猜测是，列uf的模式对于胶粘剂抓取器来说太过复杂以至于无法正确识别它，或者根本不被所使用的Serde支持，即'org.apache.hadoop.mapred.TextInputFormat'或{{1 }}。