[FLINK-3497] Add SQL scalar functions to Table API

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Component/s: Table SQL / API
• Assignee: Timo Walther
• Reporter: Timo Walther
• Created: 24/Feb/16 12:47
• Updated: 15/Mar/18 10:33
• Resolved: 15/Mar/18 10:33

Description

In order to use the Table API as ETL tool and prepare for FLINK-2099, we need to add more scalar functions such as trim(), abs(), like(), etc.

Calcite implements the most important functions. We can basically forward calls to Calcites built-in runtime functions. Some functions need special treatment because of Flink specifics.

I would propose the following steps:

• Implement TRIM, SUBSTRING as reference design
• remaining string functions
• math functions
• Date/time functions
• System functions
• Case function
• Array functions
• other

Each step includes implementation, test and documentation.

Sub-Tasks

• Implement TRIM, SUBSTRING as reference design for Table API: Closed
• Implement more String functions for Table API: Resolved
• Implement math functions for Table API: Resolved
• Reintroduce Date/Time and implement scalar functions for it: Resolved
• Add CASE function to Table API: Resolved
• Create FLOOR/CEIL function: Resolved