Question

I can’t quite get this right.. my function looks like:

create or replace function myfunc(integer, varchar(25), varchar(25), integer, integer) returns numeric as $$
declare var_return numeric;

begin

select sum(a+ b) / sum(a + b + c)
from mytable
where col1 = $1
and col2 = $2
and col3 = $3
and col4 between $4 AND $5
into var_return;

exception when division_by_zero then return 0.0;

return coalesce(var_return, 0.0);

end;

$$ language plpgsql;

But when I do select myfunc(123, 'foo', 'bar', 1, 10); I see:

ERROR:  control reached end of function without RETURN
CONTEXT:  PL/pgSQL function "myfunc"

Why does this happen? Clearly I want to catch when the select statement encounters a case where a + b + c equals 0 and return 0.

Answer 1

The EXCEPTION clause pertains to the entire BEGIN block, and runs until the END. That is, Postgres understands you to have written this:

create or replace function myfunc(...) returns ... as $$
  declare var_return numeric;

  begin
    select ...
    into var_return; -- but no RETURN statement in this block
  exception when division_by_zero then
    return 0.0;
    return coalesce(var_return, 0.0); -- this is part of the exception handler
  end;
$$ language plpgsql;

Move your “RETURN COALESCE…” above the EXCEPTION line, and try again.