Re: sql function with empty row

On 05/16/2018 11:07 AM, Philipp Kraus wrote:
> Hello,
> 
> I have defined a SQL function
> 
> CREATE OR REPLACE FUNCTION substancetrivialname(text)
>      RETURNS substance
>      LANGUAGE 'sql'
>      COST 100
>      VOLATILE
> AS $BODY$
> select s.* from substancetrivialname n
>      join substance s on s.id = n.idsubstance
>     where lower(btrim(n.name)) = lower(btrim($1));
> $BODY$;
> 
> substance and substancetrivialname have got a 1-to-N relationship (for each substance can exist multiple trivial
names).
> If I call the function with a non-existing trivial name it returns a single row with all fields are set to NULL.

Since there can be many trivial names per substance shouldn't you be 
using SETOF?:

https://www.postgresql.org/docs/10/static/xfunc-sql.html#XFUNC-SQL-FUNCTIONS-RETURNING-SET

> 
> If I run the join query directly it returns an empty record set on a non-existing trivial name.
> I expected equal behavior on my function, so my question is, how can I fix this?
> 
> Thanks
> 
> Phil
> 
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com