PSQL Stored Functions

It is now possible to write a scalar function in PSQL and call it just like an internal function.

Syntax for the DDL

  {CREATE [OR ALTER] | ALTER | RECREATE} FUNCTION <name>
  [(param1 [, ...])]
  RETURNS <type>
  AS
  BEGIN
    ...
  END

The CREATE statement is the declaration syntax for PSQL functions, parallel to DECLARE for legacy UDFs.

Example

CREATE FUNCTION F(X INT) RETURNS INT
AS
BEGIN
  RETURN X+1;
END;
SELECT F(5) FROM RDB$DATABASE;