[CALCITE-5198] Expand table function document to introduce what makes a table function to be polymorphic, why we need this and give examples to explain how to use it

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core
• Assignee: Unassigned
• Reporter: Jing Zhang
• Created: 25/Jun/22 05:21
• Updated: 01/Jul/22 15:30

Description

CALCITE-4864 allows table functions to be polymorphic, which means they have ability to take and return tables with row type not declared at design time. You could find more information in detail in CALCITE-4864.

To make it more clear to users, this JIRA aims to update table functions doc to add description of this.

It includes the following points:

• What makes table functions to be polymorphic
• Why would you use them
• Lists some examples
• For table function author, how to create and implement one
• For query author, how to use one in query