postgresql - Syntax error at or near "unnest" -

this request:

unnest('{1,2}'::int[]);

gives me error:

syntax error @ or near "unnest"

neither unnest('{1,2}'); works

why?

intire:

create or replace function result() returns setof  users              $$             declare              begin             unnest('{1,2}'::int[]);  return query select *   users;             end;             $$ language plpgsql;             select result(); 

edit core idea:

to retrive , manipualate bigint[] stored inside in column. so, have got this:

select * users email = email_ limit 1 usr;

then, usr.chain contains bigint[] data. example, {1,2,3,4,5,6,7,8,9,10}. want save 4 last of them.

how retrieve {7,8,9,10} , {1,2,3,4,5,6} , iterate on these arrays?

i found solution use select unnest(usr.chain) x order x asc limit (sdl - mdl) offset mchain , on. unnest function gives me stupid error. i'm not understand why happends. doesn't work in sucj easy case wrote @ beginning of question. subarray function doesn't work because of data type bigint[] not int[]

futher more, code unnest(array[1,2]) gives me same error. http://www.postgresql.org/docs/9.2/static/functions-array.html same error array_append function

to iterate on array:

create or replace function someresult(somearr bigint[] ) returns setof     bigint  $$ declare   integer;   x bigint; begin  x in select unnest($1)    loop --    return next x;    end loop;  --  or   in array_lower($1, 1) .. array_upper($1, 1)      loop       -- like:     return next ($1)[i];     end loop;   end; $$ language plpgsql;  select someresult('{1,2,3,4}') ; 

---

array_append ....

create or replace function someresult2(somearr bigint[],val bigint ) returns  bigint[]  $$ declare   somenew_arr bigint[]; begin somenew_arr = array_append($1, $2 ); return somenew_arr;  end; $$ language plpgsql; select someresult2('{1,2,3,4}' ,222) ; 

so, here have basic example how iterate , append arrays. can write step step want do, achieve .