Using Custom SQL functions for queries with Postgres and GraphQL

This text discusses how to use custom SQL functions for queries with Postgres and GraphQL. Custom SQL functions are procedures that can be defined and stored in a database, allowing business logic to be run directly on the database itself. Currently, only certain types of Postgres functions can be queried in the GraphQL API. Access control permissions configured for the SETOF table of a function are also applicable to the function itself. The text provides two examples of how to query functions in the GraphQL API: a custom text-search function and a PostGIS-based function. It also mentions that support for more function types and for functions in mutations is on its way.