Invalid usage of tables in PRIOR and CONNECT BY causes Internal Server Error

Detail name	Value
Changelog Number	21791
Type	Bug
Status	Resolved
Affected Versions	Exasol 8.6.0
Fix Versions	Exasol 2025.1.9, Exasol 2026.1.0, Exasol 2025.2.1
Resolution Date	2026-02-18

Description

Queries using functions like PRIOR, CONNECT_BY_ROOT, ROOT expect expressions as input.
Tables given as input cause an internal server error.
Example:

create table X as select 'a' as a from dual;

-- Expected: SyntaxError: tables are not allowed in this context
-- Observed: Internal Server Error
with k1(y) as ( values between 1 and 5 )
select
    k1.*
    , sys_connect_by_path(y, '-') as pth
    , prior X || ' > ' as X
from k1
connect by
    y = prior y+1
    start with y = 1;

Workaround

As this is an invalid query, there is no workaround.

Fix

The incorrect usage of tables as input with functions like PRIOR is now met with a proper syntax error tables are not allowed in this context.