On Tue, 25 Mar 2025 at 19:07, Tom Lane <t...@sss.pgh.pa.us> wrote:
> Alexander Farber <alexander.far...@gmail.com> writes: > > Then I am trying to add a function, which would receive a series of > > locations (longitude and latitude pairs in microdegrees) and return a > list > > of lowercase 2-letter country codes, like "de", "pl", "lv": > > > CREATE OR REPLACE FUNCTION find_countries(locations BIGINT[][]) > > RETURNS TABLE (country TEXT) AS $$ > > Postgres isn't too friendly to representing a list of locations as > a 2-D array, because we generally don't treat arrays as being > arrays-of-arrays, so unnest produces a set of bigints not a set > of smaller arrays. You might be best advised to create a composite > type like "location (long bigint, lat bigint)" and use an array of > that. If you're really hot to use a 2-D array, the only construct > I can think of that's on board with unnesting that the way you need > is plpgsql's FOREACH SLICE syntax: > > > https://www.postgresql.org/docs/devel/plpgsql-control-structures.html#PLPGSQL-FOREACH-ARRAY > > You could probably make a custom version of unnest that uses that > and then keep your query about the same. > > regards, tom lane > > > Another approach I use is to string everything into a JSON object, and de-serialize it in the function.
