Question

我目前正在使用h2版本1.4.196。我有一个CSV文件，如下所示，

Status,message,code
1,hello,13
2,world,14
3,ciao,26

以下查询按预期工作＆amp;返回正确的状态值。

select "Status" from  CSVREAD('myfile.csv', 
'Status,message,code', null) ;

以下查询会产生异常。它似乎是文字字符串＆＃34; Status＆＃34;正在传递转换而不是由返回的值执行查询。我不确定我对转换的理解是否正确正确。请帮我修复此查询以返回所需的结果。提前谢谢。

select convert("Status", int) from  CSVREAD('myfile.csv', 'Status,message,code', null) ;

Caused by: java.lang.NumberFormatException: For input string: "Status" 
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) 
    at java.lang.Integer.parseInt(Integer.java:580) 
    at java.lang.Integer.parseInt(Integer.java:615) 
    at org.h2.value.Value.convertTo(Value.java:940)

----------------------详细例外----------------------- -------

select convert("Status", int) from  CSVREAD('myfile.csv', 
'Status,message,code', null) ;
Data conversion error converting "Status"; SQL statement:
select convert("Status", int) from  CSVREAD('myfile.csv', 
'Status,message,code', null) [22018-196] 22018/22018 (Help)
org.h2.jdbc.JdbcSQLException: Data conversion error converting "Status"; SQL statement:
select convert("Status", int) from  CSVREAD('myfile.csv', 
'Status,message,code', null) [22018-196] 
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:345) 
    at org.h2.message.DbException.get(DbException.java:168) 
    at org.h2.value.Value.convertTo(Value.java:996) 
    at org.h2.expression.Function.getSimpleValue(Function.java:945) 
    at org.h2.expression.Function.getValueWithArgs(Function.java:1196) 
    at org.h2.expression.Function.getValue(Function.java:591) 
    at org.h2.command.dml.Select$LazyResultQueryFlat.fetchNextRow(Select.java:1459) 
    at org.h2.result.LazyResult.hasNext(LazyResult.java:79) 
    at org.h2.result.LazyResult.next(LazyResult.java:59) 
    at org.h2.command.dml.Select.queryFlat(Select.java:519) 
    at org.h2.command.dml.Select.queryWithoutCache(Select.java:625) 
    at org.h2.command.dml.Query.queryWithoutCacheLazyCheck(Query.java:114) 
    at org.h2.command.dml.Query.query(Query.java:371) 
    at org.h2.command.dml.Query.query(Query.java:333) 
    at org.h2.command.CommandContainer.query(CommandContainer.java:113) 
    at org.h2.command.Command.executeQuery(Command.java:201) 
    at org.h2.jdbc.JdbcStatement.executeInternal(JdbcStatement.java:186) 
    at org.h2.jdbc.JdbcStatement.execute(JdbcStatement.java:164) 
    at org.h2.server.web.WebApp.getResult(WebApp.java:1380) 
    at org.h2.server.web.WebApp.query(WebApp.java:1053) 
    at org.h2.server.web.WebApp$1.next(WebApp.java:1015) 
    at org.h2.server.web.WebApp$1.next(WebApp.java:1002) 
    at org.h2.server.web.WebThread.process(WebThread.java:164) 
    at org.h2.server.web.WebThread.run(WebThread.java:89) 
    at java.lang.Thread.run(Thread.java:748) 
Caused by: java.lang.NumberFormatException: For input string: "Status" 
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) 
    at java.lang.Integer.parseInt(Integer.java:580) 
    at java.lang.Integer.parseInt(Integer.java:615) 
    at org.h2.value.Value.convertTo(Value.java:940) 
    ... 22 more

Answer 1

您使用它的方式是您定义列并阅读csv中的所有行，因此您也可以使用Status获取第一行。然后你尝试将字符串Status转换为显然导致exeption的整数。

相反，你不应该定义列，但让h2从csv的第一行获取它们：

select convert(status,int) from CSVREAD('myfile.csv');

H2数据库问题：使用CSVREAD和转换函数进行列解释

1 个答案: