[
https://issues.apache.org/jira/browse/HIVE-16513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15980577#comment-15980577
]
Carter Shanklin commented on HIVE-16513:
----------------------------------------
Further note, the error you get for the case items is:
select width_bucket(5, c2, case c1 when 1 then c1 * 2 else c1 * 3 end, 10) from
e011_01;
OK
Failed with exception
java.io.IOException:org.apache.hadoop.hive.ql.metadata.HiveException: Error
evaluating width_bucket(5, c2, CASE WHEN ((c1 = 1)) THEN ((c1 * 2)) ELSE ((c1 *
3)) END, 10)
Time taken: 0.087 seconds
> width_bucket issues
> -------------------
>
> Key: HIVE-16513
> URL: https://issues.apache.org/jira/browse/HIVE-16513
> Project: Hive
> Issue Type: Bug
> Reporter: Carter Shanklin
>
> width_bucket was recently added with HIVE-15982. This ticket notes a few
> issues.
> Usability issue:
> Currently only accepts integral numeric types. Decimals, floats and doubles
> are not supported.
> Runtime failures: This query will cause a runtime divide-by-zero in the
> reduce stage.
> select width_bucket(c1, 0, c1*2, 10) from e011_01 group by c1;
> The divide-by-zero seems to trigger any time I use a group-by. Here's another
> example (that actually requires the group-by):
> select width_bucket(c1, 0, max(c1), 10) from e011_01 group by c1;
> Advanced Usage Issues:
> Suppose you have a table e011_01 as follows:
> create table e011_01 (c1 integer, c2 smallint);
> insert into e011_01 values (1, 1), (2, 2);
> Compile-time problems:
> You cannot use simple case expressions, searched case expressions or grouping
> sets. These queries fail:
> select width_bucket(5, c2, case c1 when 1 then c1 * 2 else c1 * 3 end, 10)
> from e011_01;
> select width_bucket(5, c2, case when c1 < 2 then c1 * 2 else c1 * 3 end, 10)
> from e011_01;
> select width_bucket(5, c2, max(c1)*10, cast(grouping(c1, c2)*20+1 as
> integer)) from e011_02 group by cube(c1, c2);
> I'll admit the grouping one is pretty contrived but the case ones seem
> straightforward, valid, and it's strange that they don't work. Similar
> queries work with other UDFs like sum. Why wouldn't they "just work"? Maybe
> [~ashutoshc] can lend some perspective on that?
> Interestingly, you can use window functions in width_bucket, example:
> select width_bucket(rank() over (order by c2), 0, 10, 10) from e011_01;
> works just fine. Hopefully we can get to a place where people implementing
> functions like this don't need to think about value expression support but we
> don't seem to be there yet.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
