sql - returning value from execute query string in plpgsql -

i'm trying return id function this:

create or replace function fx (mytable text, myvalue text) returns int $$ declare   sqlquery text;   resultid int; begin   sqlquery :=     'insert '     || mytable || ' (id, some_column) values'     || ' ('     || 'nextval(' ||  quote_literal('seq_' || mytable) || ')'     || ',' || myvalue     || ') returning id ' || resultid;    execute sqlquery;   return resultid;  end; $$ language plpgsql;  select fx('some_table', 'some_value'); 

but not working.

how can id sql query string executed?

create or replace function fx (mytable text, myvalue text) returns int $body$ declare     sqlquery text;     resultid int; begin      sqlquery := format ($$         insert %i (id, some_column) values ($1, $2)         returning id         $$, mytable     );     execute sqlquery         resultid         using nextval('seq_' || mytable), myvalue;     return resultid;  end; $body$ language plpgsql; 

use %i format specifier pass identifiers , execute using pass data parameters.