“数组值必须以我的plpgsql函数中的”{“开头

Question

我对这个问题非常沮丧。我在pl / pgsql中编写了一个merge-sort函数，如下所示：

create or replace function merge(a int[],low int, high int) returns int[]
as $$
declare mid int;
        i int;
        left_low int;
        right_low int;
        temp int[];
begin
    mid = (low + high)/2;
    left_low = low;
    right_low = mid+1;
    temp = array_fill(0,array[high - low +1],array[low]);
    i=low;
    while (left_low  <= mid and right_low <= high)  loop
        if (a[left_low] < a[right_low]) then
            temp[i] = a[left_low];
            left_low = left_low+1;
            i=i+1;
        else 
            temp[i] = a[right_low];
            right_low = right_low+1;
            i=i+1;
        end if;
    end loop;
    while ( left_low <= mid)  loop
        temp[i] = a[left_low];
        left_low = left_low+1;
        i=i+1;
    end loop;
    while ( right_low <= high)  loop
        temp[i] = a[right_low];
        right_low = right_low+1;
        i=i+1;
    end loop; 
    for i in low..high loop
        a[i] = temp[i];
    end loop;
    return a;
end;
$$ language plpgsql;

create or replace function merge_sort(arr int[],low int, high int) returns int[] as $$
declare mid int;
    left_part int[];
    right_part int[];
    b int[];
begin
    if (low < high)  then
    mid = (low + high)/2;
    left_part = merge_sort(arr,low,mid);
    right_part = merge_sort(arr,mid+1,high);
    b = left_part || right_part;
    b = merge(b,low,high);
    return b;
    end if;

    if (low = high) then 
    return arr; 
    end if; 
end;
$$ language plpgsql;

select merge_sort(array[1,6,7,2,45,6,3,8],1,8);

它引发了“数组值必须以”{“或维度信息”开头的错误，如您所见：

ERROR:  array value must start with "{" or dimension information
CONTEXT:  PL/pgSQL function merge_sort(integer[],integer,integer) line 12 at assignment
SQL statement "SELECT merge_sort(arr,low,mid)"
PL/pgSQL function merge_sort(integer[],integer,integer) line 9 at assignment
PL/pgSQL function merge_sort(integer[],integer,integer) line 9 at assignment

那很奇怪！函数“merge_sort（arr int []，low int，high int）”arr的参数声明为“int []”，显然是一个数组。

请帮帮我。谢谢。