Declaring empty, non-NULL array in plpgsql

[CSN]

Is there a way to declare an array in plpgsql so that
it's empty (not NULL)? The following causes arr to end
up being NULL:

arr varchar[];
-- do stuff with arr..
arr = array_append(ar r, '','');
And this causes an unwanted element at the front:

arr varchar[] := array[''''];
-- do stuff with arr..
arr = array_append(ar r, '','');
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[Tom Lane]

CSN <co************ *******@yahoo.c om> writes:

Is there a way to declare an array in plpgsql so that
it's empty (not NULL)?

Sure. An empty-array literal is '{}', so:

regression=# create function foo(int) returns varchar[] as '
regression'# declare
regression'# arr varchar[] := ''{}'';
regression'# begin
regression'# for i in 1..$1 loop
regression'# arr = array_append(ar r, i::varchar);
regression'# end loop;
regression'# return arr;
regression'# end' language plpgsql;
CREATE FUNCTION
regression=# select foo(10);
foo
------------------------
{1,2,3,4,5,6,7, 8,9,10}
(1 row)
regards, tom lane

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