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https://issues.apache.org/jira/browse/HIVE-10120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15999540#comment-15999540
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Dudu Markovitz edited comment on HIVE-10120 at 5/7/17 9:00 AM:
---------------------------------------------------------------
1.
I'm truly puzzled here.
Why put a limitation on the *create* statement instead of removing the
limitation from the *select* statement?
There seems to be no logical reason to prohibit queries such as *select
`a.b.c`*.
2.
A)
*CTAS* was not handled and it still possible to create tables that could not be
queried
{code}
hive> create table t as select 1 as `a.b.c`;
OK
hive> desc t;
OK
col_name data_type comment
a.b.c int
Time taken: 0.441 seconds, Fetched: 1 row(s)
hive> select * from t;
FAILED: RuntimeException java.lang.RuntimeException: cannot find field a from
[0:a.b.c]
{code}
B)
*alter table ... change column* was not handled and it still possible to rename
a column such that the table could not be queried
{code}
create table t (i int);
alter table t change column i `a.b.c` int
select * from t;
Error while compiling statement: FAILED: RuntimeException
java.lang.RuntimeException: cannot find field a from [0:a.b.c]
{code}
was (Author: dmarkovitz):
1.
I'm truly puzzled here.
Why put a limitation on the *create* statement instead of removing the
limitation from the *select* statement?
There seems to be no logical reason to prohibit queries such as *select
`a.b.c`*.
2.
A)
*CTAS* was not handled and it still possible to create tables that cannot be
queried
{code}
hive> create table t as select 1 as `a.b.c`;
OK
hive> desc t;
OK
col_name data_type comment
a.b.c int
Time taken: 0.441 seconds, Fetched: 1 row(s)
hive> select * from t;
FAILED: RuntimeException java.lang.RuntimeException: cannot find field a from
[0:a.b.c]
{code}
B)
*alter table ... change column* was not handled and it still possible to rename
a column to unqueryable name.
{code}
create table t (i int);
alter table t change column i `a.b.c` int
select * from t;
Error while compiling statement: FAILED: RuntimeException
java.lang.RuntimeException: cannot find field a from [0:a.b.c]
{code}
> Disallow create table with dot/colon in column name
> ---------------------------------------------------
>
> Key: HIVE-10120
> URL: https://issues.apache.org/jira/browse/HIVE-10120
> Project: Hive
> Issue Type: Improvement
> Components: Parser
> Reporter: Pengcheng Xiong
> Assignee: Pengcheng Xiong
> Labels: TODOC1.2
> Fix For: 1.2.0
>
> Attachments: HIVE-10120.01.patch, HIVE-10120.02.patch
>
>
> Since we don't allow users to query column names with dot in the middle such
> as emp.no, don't allow users to create tables with such columns that cannot
> be queried. Fix the documentation to reflect this fix.
> Here is an example. Consider this table:
> {code}
> CREATE TABLE a (`emp.no` string);
> select `emp.no` from a; fails with this message:
> FAILED: RuntimeException java.lang.RuntimeException: cannot find field emp
> from [0:emp.no]
> {code}
> The hive documentation needs to be fixed:
> {code}
> (https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL) seems
> to indicate that any Unicode character can go between the backticks in the
> select statement, but it doesn’t like the dot/colon or even select * when
> there is a column that has a dot/colon.
> {code}
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