No, the example is correct. Referring to the documentation above that:
If the width argument is negative, the result is left aligned (as if the - flag had been specified) ...
This applies even if the "-" flag is also specified. So the last example is meant to illustrate that 2 minuses don't make a plus here.
That's very unusual, IMO. This behavior follows some SQL standard or is it an invention of PostgreSQL?
this is postgresql feature - standard doesn't support any similar functionality - and printf is some like developer Esperanto. We significantly reduced complexity of printf function and we modified basic rules for usage in SQL, but some very typical rules - like format placeholders, we share - we don't introduce own rules there.
