LIKE expressions do not match constant strings in subselects

Detail name	Value
Changelog Number	7306
Type	Bug
Status	Resolved
Affected Versions	Exasol 6.1.0
Fix Versions	Exasol 6.1.1
Resolution Date	2019-01-07

How to reproduce
Given this table

create or replace table t(a varchar(100));
insert into t values 'Test123';

This query gives NULL instead of true:

SELECT A LIKE 'Test123' as should_be_true, A FROM 
 (select 'Test123' as a from t group by a);

while this query works:

SELECT A LIKE 'Test123' as should_be_true, A FROM 
 (select a from t group by a);

Workaround
Add a cast to VARCHAR for the constant expression in the sub-select:

SELECT A LIKE 'Test123' as should_be_true, A FROM 
 (select cast('Test123' as varchar(100)) as a from t group by a);