An ABAP CDS Table Function is a type of Core Data Services (CDS) artifact that allows you to define a reusable data service for a specific database table or view. A table function can be used to retrieve data from a table or view using SQL-like syntax, and it can also accept parameters to filter or transform the data that is returned.
Table functions can be created in the ABAP Development Tools (ADT) in Eclipse or in the SAP GUI using the ABAP Workbench. To create a table function, you define the input parameters, the data sources (which can include other table functions), and the output parameters.
Table functions can be used in ABAP programs, in the ABAP query builder, or in SAP Analytics Cloud. They offer a reusable way to retrieve and manipulate data from database tables and views, and can help to improve performance by reducing the amount of redundant code that needs to be written.