I have a stored procedure that stores some dynamic sql in a string (this is just an example):
CREATE PROCEDURE test RETURNS (return_variable AS VARCHAR(1000))
FOR
SELECT 'SELECT username FROM users ' FROM username INTO :return_variable
DO SUSPEND;
END

If I then run it:
SELECT return_variable
FROM test ;


Instead of returning
'SELECT username FROM users SELECT username FROM users SELECT username FROM users'

It returns 3 rows of 'SELECT username FROM users'. How do I get it to return a single string?