[CALCITE-3017] Improve null handling of JsonValueExpressionOperator

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.20.0
• Labels: pull-request-available
• Assignee: Hongze Zhang
• Reporter: Hongze Zhang
• Created: 24/Apr/19 08:03
• Updated: 24/Jun/19 15:02
• Resolved: 15/May/19 04:59

Description

In Calcite's implementation, JsonValueExpressionOperator currently returns a null value no matter the argument is JSON NULL value or SQL NULL value. But in MySQL, some JSON functions behave differently on different null inputs. For instance for a MySQL JSON function JSON_STORAGE_SIZE, if we execute:

SELECT JSON_STORAGE_SIZE(null), JSON_STORAGE_SIZE('null')

The result should be:

JSON_STORAGE_SIZE(null)	JSON_STORAGE_SIZE('null')
null	2

We should improve the operator a bit to support different behaviors.

Issue Links

• blocks: CALCITE-2985 Implement JSON_STORAGE_SIZE function
• links to: GitHub Pull Request #1203