Presto(Athena)加载带有引号转义逗号的CSV文件 [英] Presto (Athena) loading of a CSV file with quote-escaped commas

问题描述

考虑CSV文件中的以下行:

Consider the following row in a CSV file:

1,0,True,"{""foo"":null,""bar"":null}",0,1
                       ▲

突出显示的 是列的一部分.也就是说，此全文:"{""foo":null，""bar":null}" 是单个列的值.但是，AWS Athena会将突出显示的 解释为以逗号分隔的逗号，从而将该文本错误地拆分为多列.

The highlighted , is part of a column. That is, this full text: " {""foo"":null,""bar"":null}" is the value of a single column. However AWS Athena is interpreting the highlighted , as a column-delimiting comma, incorrectly splitting that text into multiple columns.

我知道我可以将列定界符更改为其他名称以避免此问题.我的问题是:这是AWS Athena/Presto中的错误吗?如何避免这些逗号?

I know I could change the column delimiter to something else to avoid this problem. My question is: Is this a bug in AWS Athena / Presto? How can I escape these commas?

推荐答案

如果数据用双引号引起来，则需要使用

If your data is enclosed in double quotes, you need to use OpenCSVSerDe .

对于示例数据，下表定义有效:

for the sample data, the following table definition works:

1,0,True,"{""foo"":null,""bar"":null}",0,1

如何在数据中转义逗号

CREATE EXTERNAL TABLE `extra_comma`(
  `a` string COMMENT 'from deserializer', 
  `b` string COMMENT 'from deserializer', 
  `c` string COMMENT 'from deserializer', 
  `d` string COMMENT 'from deserializer',
  `e` string COMMENT 'from deserializer',
  `f` string COMMENT 'from deserializer'
  )
ROW FORMAT SERDE 
  'org.apache.hadoop.hive.serde2.OpenCSVSerde' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.mapred.TextInputFormat' 
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  's3://aws-glue-stackoverflow/comma_in_data/'

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