Tim Armstrong created HIVE-24040:
------------------------------------
Summary: Slightly odd behaviour with CHAR comparisons and string
literals
Key: HIVE-24040
URL: https://issues.apache.org/jira/browse/HIVE-24040
Project: Hive
Issue Type: Bug
Reporter: Tim Armstrong
If t is a char column, this statement behaves a bit strangely - since the RHS
is a STRING, I would have expected it to behave consistently with other
CHAR/STRING comparisons, where the CHAR column has its trailing spaces removed
and the STRING does not have its trailing spaces removed.
{noformat}
select count(*) from ax where t = cast('a ' as string);
{noformat}
Instead it seems to be treated the same as if it was a plain literal,
interpreted as CHAR, i.e.
{noformat}
select count(*) from ax where t = 'a ';
{noformat}
Here are some more experiments I did based on
https://github.com/apache/hive/blob/master/ql/src/test/queries/clientpositive/in_typecheck_char.q
that seem to show some inconsistencies.
{noformat}
-- Hive version 3.1.3000.7.2.1.0-287 r4e72e59f1c2a51a64e0ff37b14bd396cd4e97b98
create table ax(s char(1),t char(10));
insert into ax values ('a','a'),('a','a '),('b','bb');
-- varchar literal preserves trailing space
select count(*) from ax where t = cast('a ' as varchar(50));
+------+
| _c0 |
+------+
| 0 |
+------+
-- explicit cast of literal to string removes trailing space
select count(*) from ax where t = cast('a ' as string);
+------+
| _c0 |
+------+
| 2 |
+------+
-- other string expressions preserve trailing space
select count(*) from ax where t = concat('a', ' ');
+------+
| _c0 |
+------+
| 0 |
+------+
-- varchar col preserves trailing space
create table stringv as select cast('a ' as varchar(50));
select count(*) from ax, stringv where t = `_c0`;
+------+
| _c0 |
+------+
| 0 |
+------+
-- string col preserves trailing space
create table stringa as select 'a ';
select count(*) from ax, stringa where t = `_c0`;
+------+
| _c0 |
+------+
| 0 |
+------+
{noformat}
[~jcamachorodriguez] [~kgyrtkirk]
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