Question

I have a postgresql table:

|  words  |  repl |
|  word1  | repl1 |
|  word2  | repl2 |
|  word3  | repl3 |    

How can I return a set of all words and repl with stored procedure.

I try:

create function get_words() returns setof text as
$$
declare
    r varchar;
begin
  for r in
      select word,repl from my_table
      loop
        return next r;
    end loop;
    return;
end
$$ language plpgsql;

When i execute it i got only word:

select * from get_words();
 get_words 
-----------
 word1
 word2
 word3

Thank you.

Answer 1

Your function is defined to return only a single column (returns text). Additionally the variable you are reading the values into is a scalar as well and cannot hold more than one value, so only the word column is put into the r variable.

You need to change the function to e.g. returns set of my_table and change the definition of the loop variable:

create or replace function get_words() 
   returns setof my_table as
$$
declare
    r words%rowtype;
begin
  for r in select w.word, w.repl from my_table w
  loop
     return next r;
  end loop;
  return;
end
$$ language plpgsql;

If you don’t intend to do anything in the loop using return query makes things a bit easier:

create or replace function get_words() 
  returns table (word text, repl text)
as
$$
begin
  return query select w.word, w.repl from words w;
end
$$ language plpgsql;

You can shorten this even further if you don’t use PL/pgSQL but a plain SQL function:

create or replace function get_words() 
   returns table (word text, repl text)
as
$$
  select w.word, w.repl from words w;
$$ language sql;