I got unexpected results when I ran this PL/pgSQL function:
CREATE FUNCTION test() RETURNS void AS $$ BEGIN FOR i IN 1 .. 0.5*5 LOOP raise notice '%', i; END LOOP; END; $$ LANGUAGE plpgsql; SELECT * FROM test();
The result of the execution is: NOTICE: 1 NOTICE: 2 NOTICE: 3
I think this result is unexpected because the last round of loop variable is beyond the specified upper bound of the loop. Is this a bug in a FOR loop?
No, a loop needs a discrete data type so that a step makes sense. So integer it is.
postgres=# select 2.5::integer;
int4 ------ 3 (1 row)
But this seems to cause incomprehensible results. If it is unsafe to take values outside the upper and lower bounds of the loop, then this will lead to unintended consequences.
That is the nature of programming. Test your code and don't write stuff that doesn't actually make sense.
Is this implicit type conversion necessary? I think there are two better ways to do it. One is to report errors directly to the user.
In retrospect this probably would have been a better outcome. Introducing an error/change now seems problematic though.
So, yes, if either bound is not an integer the value will be coerced to become an integer by the normal casting rules between those types.
