sql - 无法使用 CSV 文件中的 Presto 创建 Hive 表

Question

我想使用 Presto 创建一个 Hive 表，并将数据存储在 S3 上的 csv 文件中。

我已经在 S3 上上传了文件，我确信 Presto 能够连接到存储桶。

现在，当我发出 create table 命令时，我在查询表时将所有值(行)都设为 NULL。

我尝试调查过类似的问题，但事实证明 Presto 在 Stackoverflow 上并不那么出名。

文件中的一些行是:

PassengerId,Survived,Pclass,Name,Sex,Age,SibSp,Parch,Ticket,Fare,Cabin,Embarked
1,0,3,"Braund, Mr. Owen Harris",male,22,1,0,A/5 21171,7.25,,S
2,1,1,"Cumings, Mrs. John Bradley (Florence Briggs Thayer)",female,38,1,0,PC 17599,71.2833,C85,C
3,1,3,"Heikkinen, Miss. Laina",female,26,0,0,STON/O2. 3101282,7.925,,S
4,1,1,"Futrelle, Mrs. Jacques Heath (Lily May Peel)",female,35,1,0,113803,53.1,C123,S
5,0,3,"Allen, Mr. William Henry",male,35,0,0,373450,8.05,,S
6,0,3,"Moran, Mr. James",male,,0,0,330877,8.4583,,Q
7,0,1,"McCarthy, Mr. Timothy J",male,54,0,0,17463,51.8625,E46,S
8,0,3,"Palsson, Master. Gosta Leonard",male,2,3,1,349909,21.075,,S
9,1,3,"Johnson, Mrs. Oscar W (Elisabeth Vilhelmina Berg)",female,27,0,2,347742,11.1333,,S
10,1,2,"Nasser, Mrs. Nicholas (Adele Achem)",female,14,1,0,237736,30.0708,,C
11,1,3,"Sandstrom, Miss. Marguerite Rut",female,4,1,1,PP 9549,16.7,G6,S
12,1,1,"Bonnell, Miss. Elizabeth",female,58,0,0,113783,26.55,C103,S
13,0,3,"Saundercock, Mr. William Henry",male,20,0,0,A/5. 2151,8.05,,S
14,0,3,"Andersson, Mr. Anders Johan",male,39,1,5,347082,31.275,,S
15,0,3,"Vestrom, Miss. Hulda Amanda Adolfina",female,14,0,0,350406,7.8542,,S
16,1,2,"Hewlett, Mrs. (Mary D Kingcome) ",female,55,0,0,248706,16,,S
17,0,3,"Rice, Master. Eugene",male,2,4,1,382652,29.125,,Q
18,1,2,"Williams, Mr. Charles Eugene",male,,0,0,244373,13,,S
19,0,3,"Vander Planke, Mrs. Julius (Emelia Maria Vandemoortele)",female,31,1,0,345763,18,,S
20,1,3,"Masselmani, Mrs. Fatima",female,,0,0,2649,7.225,,C

我的 csv 文件是 here ，从这里获取 train.csv。因此，我的 presto 命令是:

create table testing_nan_4 ( PassengerId integer, Survived integer, Pclass integer, Name varchar, Sex varchar, Age integer, SibSp integer, Parch integer, Ticket integer, Fare double, Cabin varchar, Embarked varchar ) with ( external_location = 's3://my_bucket/titanic_train/', format = 'textfile' );

结果是:

 passengerid | survived | pclass | name | sex  | age  | sibsp | parch | ticket | fare | cabin | embarked
-------------+----------+--------+------+------+------+-------+-------+--------+------+-------+----------
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL
 NULL        | NULL     | NULL   | NULL | NULL | NULL | NULL  | NULL  | NULL   | NULL | NULL  | NULL

并且期望得到实际数据。

Answer 1

Starburst Presto 目前支持 CSV Hive 存储格式，请参阅:https://docs.starburstdata.com/latest/release/release-302-e.html?highlight=csv

还有一些工作正在进行中以使其在 PrestoSQL 中工作，请参阅:https://github.com/prestosql/presto/pull/920

然后你可以在 Presto Hive 连接器中使用这样的表:

CREATE TABLE hive.default.csv_table_with_custom_parameters (
    c_bigint varchar,
    c_varchar varchar)
WITH (
    csv_escape = '',
    csv_quote = '',  
    csv_separator = U&'\0001', -- to pass unicode character
    external_location = 'hdfs://hadoop/datacsv_table_with_custom_parameters',
    format = 'CSV')

在你的情况下是:

CREATE TABLE hive.default.csv_table_with_custom_parameters (
       PassengerId int, Survived int, Pclass int, Name string, Sex string, Age int, SibSp int, Parch int, Ticket int, Fare double, Cabin string, Embarked string)
WITH (
    csv_escape = '\',
    csv_quote = '"',  
    csv_separator = ',',
    external_location = 's3://my_bucket/titanic_train/',
    format = 'CSV')

请注意，csv_escape、csv_quote 和 csv_separator 表属性仅支持单个字符值。

另外 "skip.header.line.count"="1" 在 Presto 中还没有 CSV 表的等价语法。所以我建议你从数据文件中删除标题。