Обсуждение: function signature allow "default" keyword

jian he schrieb am 15.05.2023 um 10:33:
>
> function idea.
> allow function calling using the default keyword for any of the input arguments.
>
> example: https://dbfiddle.uk/FQwnfdmm
> So something like this "SELECT * FROM customer_orders(2579927, 'order_placed_on DESC', default, 2);"
> should work.


You can use named parameters when calling the function, that will use the default value for those not mentioned:

SELECT *
FROM customer_orders(_customer_id => 2579927,
                     _sort_field_and_direction => 'order_placed_on DESC',
                     _offset => 2);

On Mon, May 15, 2023 at 5:00 PM Thomas Kellerer <shammat@gmx.net> wrote:

jian he schrieb am 15.05.2023 um 10:33:
>
> function idea.
> allow function calling using the default keyword for any of the input arguments.
>
> example: https://dbfiddle.uk/FQwnfdmm
> So something like this "SELECT * FROM customer_orders(2579927, 'order_placed_on DESC', default, 2);"
> should work.


You can use named parameters when calling the function, that will use the default value for those not mentioned:

SELECT *
FROM customer_orders(_customer_id => 2579927,
                     _sort_field_and_direction => 'order_placed_on DESC',
                     _offset => 2);

select  proname
        ,proargtypes
        ,pg_get_expr(pp.proargdefaults,0,true)
        ,pronargdefaults
from    pg_proc     pp
where   pp.proname  = 'customer_orders';

----------return-------------

proname         | customer_orders

proargtypes     | 23 25 23 23 1082 1082
pg_get_expr     | 10, 0, CURRENT_DATE - 30, CURRENT_DATE
pronargdefaults | 4

table insert works, i guess because pg_attribute has column ordinal number (left to right).

but pg_proc only counts the number of arguments that have a default value.