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https://issues.apache.org/jira/browse/CALCITE-4590?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17350228#comment-17350228
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duan xiong commented on CALCITE-4590:
-------------------------------------
[~julianhyde] Hi. I have read code about this issue.But I have some confuse. In
RexBuilder Function makeLiteral:
{code:java}
case CHAR:
final NlsString nlsString = (NlsString) value;
if (trim)
{ return makeCharLiteral(nlsString.rtrim()); }
else
{ return makeCharLiteral(padRight(nlsString, type.getPrecision())); }{code}
The Char Type value has been converted to the Fixed length string. For example
'a'(char(3))->'a '. But the trim parameter make this to origin. So I want to
know why we need to trim when Type is Char.
In MySql:
{code:java}
CREATE TABLE char_test(char_col CHAR(10));
INSERT INTO char_test VALUES('string1');
INSERT INTO char_test VALUES(' string2');
INSERT INTO char_test VALUES('string3 ');
then:
select * from char_test where char_col='string3';
select * from char_test where char_col='string3 ';
select * from char_test where char_col='string3 ';
all can return:
+----------+
| char_col |
+----------+
| string3 |
+----------+{code}
PostgreSql is same as Mysql;
> Incorrect query result with fixed-length string
> -----------------------------------------------
>
> Key: CALCITE-4590
> URL: https://issues.apache.org/jira/browse/CALCITE-4590
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.26.0
> Reporter: Roman Kondakov
> Assignee: duan xiong
> Priority: Major
>
> Query may return wrong result when fixed-length strings (CHAR(N)) are used in
> OR/IN clause
> {code:java}
> @Test void test() {
> // Passed.
> CalciteAssert.that()
> .query("select * from (values (1, 'a'), (2, 'abc')) where EXPR$1 =
> 'a'")
> .returns("EXPR$0=1; EXPR$1=a \n");
> // Failed. Only "EXPR$0=2; EXPR$1=abc\n" is returned
> CalciteAssert.that()
> .query("select * from (values (1, 'a'), (2, 'abc')) where EXPR$1 =
> 'a' or EXPR$1 = 'abc'")
> .returns("EXPR$0=1; EXPR$1=a \n"
> + "EXPR$0=2; EXPR$1=abc\n");
> }
> {code}
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