[jira] [Commented] (HIVE-17724) Cast from string to float gives strange result

["Andrew Sherman (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-17724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16194757#comment-16194757 ] 

Andrew Sherman commented on HIVE-17724:
---------------------------------------

I run Java code:

{quote}long l = 1507284611L;
float f = l;
System.out.println("f = " + f);
System.out.printf("%f\n", f);{quote}

and get
{quote}f = 1.50728461E9
1507284608.000000{quote}

Floats are precise only to about 7 digits. So probably this is just a limitation of the type.
See https://stackoverflow.com/questions/13542944/how-many-significant-digits-have-floats-and-doubles-in-java

> Cast from string to float gives strange result
> ----------------------------------------------
>
>                 Key: HIVE-17724
>                 URL: https://issues.apache.org/jira/browse/HIVE-17724
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 1.1.0
>         Environment: Hive 1.1.0-cdh5.10.0
> Subversion file:///data0/jenkins/workspace/generic-package-ubuntu64-14-04/CDH5.10.0-Packaging-Hive-2017-01-20_11-52-43/hive-1.1.0+cdh5.10.0+859-1.cdh5.10.0.p0.71~trusty -r Unknown
>            Reporter: David Scarlatti
>
> this query:"select CAST ('1507284611' as int), CAST ('1507284611' as bigint),  CAST ('1507284611' as float),   CAST ('1507284611' as double),   CAST ('1507284611' as decimal)"
> returns
> 1507284611	1507284611	1507284608	1507284611	1507284611
> cast as float is the only one changing the numeric value.



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