postgresql - How to write a function that returns text or integer values? -

i'm using postgresql 9.2.4.

postgres=# select version();

                           version -------------------------------------------------------------  postgresql 9.2.4, compiled visual c++ build 1600, 64-bit (1 row) 

sqlfiddle link

my query executes insertion safely. need function should return except void datatype. text("inserted table") or integer(0-false,1-true) , useful me validate whether inserted or not?

i need syntax function returns integer or text when insertion done. validation purpose. there way solve this?

what need

most need 1 function return text , 1 return integer or function returns boolean indicate success. of trivial , i'll refer excellent manual on create function or code examples in similar questions on so.

what asked

how write function returns text or integer values?

... in sense have one return type being either text or integer. not trivial, not impossible has been suggested. key word is: polymorphic types.

building on simple table:

create table tbl(   tbl_id int,   txt    text,   nr     int ); 

this function returns either integer or text (or other type if allow it), depending on input type.

create function f_insert_data(_id int, _data anyelement, out _result anyelement)   returns anyelement $func$ begin  case pg_typeof(_data)  when 'text'::regtype     insert tbl(tbl_id, txt) values(_id, _data)     returning txt     _result;  when 'integer'::regtype     insert tbl(tbl_id, nr) values(_id, _data)     returning nr     _result;  else     raise exception 'unexpected data type: %', pg_typeof(_data)::text; end case;  end $func$ language plpgsql; 

call:

select f_insert_data(1, 'foo'::text);  -- explicit cast needed. select f_insert_data(1, 7); 

simple case

one function returns true / false indicate whether row has been inserted, 1 input parameter of varying type:

create function f_insert_data2(_id int, _data anyelement)   returns boolean $func$ begin  case pg_typeof(_data) when 'text'::regtype    insert tbl(tbl_id, txt) values(_id, _data);  when 'integer'::regtype    insert tbl(tbl_id, nr) values(_id, _data);  else    raise exception 'unexpected data type: >>%<<', pg_typeof(_data)::text; end case;  if found return true; else return false; end if;  end $func$ language plpgsql; 

the input type can replaced text parameter purposes, can cast , other type.