Bug: Query returns nulls in DBeaver and not other clients

The following query returns nulls in DBeaver but not other clients

select
  t.*,
  CAST( CAST(t.date_key AS CHAR(8)) AS DATE FORMAT 'YYYYMMDD')
from schema.test_table as t

looking at the tooltip it looks like dbeaver is confused on the type of the result given that its showing the datetime icon but hovering says integer?

CREATE MULTISET TABLE schema.test_table ,NO FALLBACK ,
     NO BEFORE JOURNAL,
     NO AFTER JOURNAL,
     CHECKSUM = DEFAULT,
     DEFAULT MERGEBLOCKRATIO
     (
      date_key INTEGER NOT NULL
     )
no primary index;

insert into schema.test_table values (20100101);
insert into schema.test_table values (20100102);
insert into schema.test_table values (20100103);
insert into schema.test_table values (20100104);

[serge-rider]

This is what causes problem with date values:

Unrecognized type 'java.sql.Date' - can't convert to numeric

DBeaver thinks that this column has numeric data type. This is because you second column has the same alias as the real table column (date_key). DBeaver tries to discover real attribute data type from database metadata whenever it is possible. Smarty pants.

Workaround - set some alias for your expression. And I’ll think how to handle this problem better…

[r-richmond]

makes sense… given that here is code that reproduces the issue in oracle

create table schema.test_table as select 20100101 as date_key from dual;

select
  t.*,
  to_date(cast(t.date_key as varchar(8)),'YYYYMMDD') as date_key
from schema.TEST_TABLE t;