Queries containing virtual tables and FALSE predicates may lead to an internal server error
Details
| Detail name | Value |
|---|---|
| Changelog Number | 11134 |
| Type | Bug |
| Status | Resolved |
| Affected Versions | Exasol 6.2.0, Exasol 7.0.0 |
| Fix Versions | Exasol 7.0.4, Exasol 6.2.12 |
| Resolution Date | 2020-11-13 |
Description
A query that meets the following conditions will return an internal server error:
- A query contains a subselect
- The subselect references a virtual table
- A WHERE condition evaluates to FALSE (ex. WHERE 1=0 or WHERE FALSE)
- This filter filters out all rows of the subselect
Example:
select x from (select max(a) x from virtual_schema.virtual_table) where false;
Workaround
You can encapsulate the subselect containing the virtual table with another subselect to avoid the internal server error. For example:
select x from (select x from (select max(a) x from virtual_schema.virtual_table)) where false;
Fix
These types of queries will run as expected.
