[FLINK-14321] Support to parse watermark statement in SQL DDL

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.10.0
• Component/s: Table SQL / API
• Labels: pull-request-available
• Assignee: Jark Wu
• Reporter: Jark Wu
• Created: 05/Oct/19 03:17
• Updated: 25/Oct/19 06:55
• Resolved: 25/Oct/19 06:55

Description

Support to parse watermark syntax in SQL DDL. This can implemented in flink-sql-parser module.

The watermark syntax is as following:

WATERMARK FOR columnName AS <watermark_strategy_expression>

We should also do some validation during parsing, for example, whether the referenced rowtime field exist. We should also support to reference a nested field as the rowtime field.

Issue Links

• links to: GitHub Pull Request #9952