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https://issues.apache.org/jira/browse/DRILL-3014?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17125847#comment-17125847
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benj commented on DRILL-3014:
-----------------------------
This problem seems to have been corrected (it's not possible to reproduce in
1.17)
> Casting unknown field yields different result from casting null, and bad
> error message
> --------------------------------------------------------------------------------------
>
> Key: DRILL-3014
> URL: https://issues.apache.org/jira/browse/DRILL-3014
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Relational Operators
> Reporter: Daniel Barclay
> Priority: Minor
> Fix For: Future
>
>
> Casting null to INTEGER works as expected like this:
> {noformat}
> 0: jdbc:drill:zk=local> select cast(NULL AS INTEGER) from
> `dfs.tmp`.`simple.csv`;
> +------------+
> | EXPR$0 |
> +------------+
> | null |
> +------------+
> 1 row selected (0.15 seconds)
> 0: jdbc:drill:zk=local>
> {noformat}
> (File "{{simple.csv}}" contains one line containing simply "{{a,b,c,d}}".)
> However, casting an unknown column yields an error:
> {noformat}
> 0: jdbc:drill:zk=local> select cast(noSuchField AS INTEGER) from
> `dfs.tmp`.`simple.csv`;
> Error: SYSTEM ERROR: null
> Fragment 0:0
> [Error Id: a0b348ec-f2c5-4f66-9f05-591399f3c315 on dev-linux2:31010]
> (state=,code=0)
> 0: jdbc:drill:zk=local>
> {noformat}
> This looks like a JDK {{NumberFormatException}} that wasn't handled
> properly*, and looks like the logical null from the non-existent column was
> turned into the string "{{null}}" before the cast to {{INTEGER}}.
> Is that a bug or is it intentional that the non-existent field in this case
> is not actually treated as being all nulls (as non-existent fields are in at
> least some other places)?
> (*For most NumberFormatExceptions, the message text does not contain the
> information that the kind of exception was a number-format exception--that
> information is only in the class name. In particular that information is not
> in the message text returned by getMessage().
> Drill code that can throw a {{NumberFormatException}} (e.g., cast functions
> and other code that calls, e.g., {{Integer.parse(...)}}) should either
> immediately wrap it in a {{UserException}}, or at least wrap it in another
> {{NumberFormatException}} with fuller message text.)
> This seem to confirm that it's a {{NumberFormatException}} (note the
> first-column value "{{a}}"):
> {noformat}
> select cast(columns[0] AS INTEGER) from `dfs.tmp`.`simple.csv`;
> Error: SYSTEM ERROR: a
> Fragment 0:0
> [Error Id: 9d6107dc-dc2a-40ce-9676-6387ab427098 on dev-linux2:31010]
> (state=,code=0)
> 0: jdbc:drill:zk=local>
> {noformat}
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