Обсуждение: help using arrays in a function

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"Jennifer Lee" <jlee@scri.sari.ac.uk> writes:
>                         WHILE a[i] LOOP

> I'm now testing our database on 7.4 and get an error with this function
> and I can't figure out how to fix it.
> ERROR:  invalid input syntax for type boolean: "100"
> CONTEXT:  PL/pgSQL function "array_element_compare" line 9 at while

plpgsql now enforces that the test expression of IF, WHILE, etc must be
a boolean.  The above is not.

This is pretty poor coding practice anyway, since even before 7.4 it
would have given wrong answers for arrays containing zeroes or arrays
whose lower index bound is not 1.  I'd suggest using the array_lower and
array_upper functions to determine the valid range of subscripts.
Something like

    FOR i IN array_lower(a,1) .. array_upper(a,1) LOOP

should work.

            regards, tom lane

Jennifer Lee wrote:
>            WHILE a[i] LOOP

This problem has nothing to do with arrays, per se. PL/pgSQL no longer
assumes it can coerce an integer constant to a boolean. Instead make the
above line look like this:

              WHILE a[i] IS NOT NULL LOOP


BTW, in 7.4 you could more easily get the same result like this:

regression=# select 82 = any ('{100,92,82}');
  ?column?
----------
  t
(1 row)

regression=# select 82 = any ('{100,92}');
  ?column?
----------
  f
(1 row)

See:
http://www.postgresql.org/docs/current/static/functions-comparisons.html

HTH,

Joe