Internal server error when using non-boolean expression in START WITH clause of CONNECT BY

Detail name	Value
Changelog Number	5832
Type	Bug
Status	Resolved
Affected Versions	EXASOL 6.0.0, EXASolution 5.0.0
Fix Versions	EXASOL 6.0.8
Resolution Date	2018-03-05

Problem Description

When using CONNECT BY with a START WITH clause that is no boolean expression, the statement terminates with 'internal server error' error message. If START WITH contains a correct start condition, there is no problem.

Expected behavior

The statement should result in a exception stating that START WITH has to be a a boolean expression.

Example

CREATE SCHEMA test;
CREATE OR REPLACE TABLE connect_me (id int, parent_id int, name varchar(10));

-- internal server error
SELECT LEVEL, c.* FROM connect_me AS c CONNECT BY PRIOR parent_id = id
START WITH 'xxx';

-- ok (compare expression)
SELECT LEVEL, c.* FROM connect_me AS c CONNECT BY PRIOR parent_id = id
START WITH name = 'xxx';

-- ok (general boolean expression)
SELECT LEVEL, c.* FROM connect_me AS c CONNECT BY PRIOR parent_id = id
START WITH true;

Workaround

If you encounter this problem your statement has a wrong START WITH expression. Simply correct it and the statement will work.