Re: Argument casting hierarchy?

On 7/1/19 12:18 PM, Wells Oliver wrote:
> Hi guys, hoping you can help clarify what the 'hierarchy' of casts might
> be in function arguments.
>
> Meaning I have the following two functions
>
> stats.foo1 (a bigint, b bigint) returns a/b::numeric
>
> stats.foo1 (a real, b real) returns a/b::numeric
>
> It's essentially the same function, but I thought I had to create two to
> accept the different types.
>
> However, when I call stats.foo1(3::smallint, 4::smallint) I receive the old:
>
> ERROR:  function stats.foo(smallint, smallint) is not unique
>
> Along w/ the message to explicitly cast.
>
> I am essentially trying to write one function that will cast "down", I
> guess, anything smaller than what's passed. I am guessing I only need
> the real/real argument signature, but I wanted some clarity from the group.

From the system catalogs, where float4 = real:

select typname AS cast_target from pg_cast join pg_type on
pg_cast.casttarget = pg_type.oid where castsource = 'float4'::regtype;
cast_target
-------------
int8
int2
int4
float8
numeric

select typname AS cast_target from pg_cast join pg_type on
pg_cast.casttarget = pg_type.oid where castsource = 'numeric'::regtype;
cast_target
-------------
int8
int2
int4
float4
float8
money
numeric
(7 rows)

>
> I appreciate it.
>
> --
> Wells Oliver
> wells(dot)oliver(at)gmail(dot)com <mailto:wellsoliver(at)gmail(dot)com>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com