[CALCITE-6149] ClickHouseSqlDialect should support cast to Nullable

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.36.0
• Fix Version/s: 1.37.0
• Component/s: core
• Labels: dialect pull-request-available
• Assignee: Unassigned
• Reporter: ChenLuyang
• Created: 01/Dec/23 10:05
• Updated: 06/May/24 22:19
• Resolved: 08/Jan/24 19:15

Description

In ClickHouse, there is an issue with RelDataType of Nullable type when casting to a non-Nullable type. For example, SELECT CAST(NULL, 'Int32') will throw an error. In such cases, we should use SELECT CAST(NULL, 'Nullable(Int32)') instead.

 

related error messages.

DB::Exception: Cannot convert NULL value to non-Nullable type

Issue Links

• links to: GitHub Pull Request #3556