Question

我正在尝试使用plpgsql在函数内部创建一个视图，它返回“小”表的x列，定义为（x integer，y integer）。

create or replace function skyline_naive2(dataset text) returns setof integer as
$$
declare 
    fullx text;
begin
    fullx = dataset||'_skyline_naive2';
    execute format('create view %s as select x,y from %s',fullx,dataset);
    return query select x from fullx;
end
$$ language plpgsql;

select * from skyline_naive2('small');

返回“关系fullx不存在”

我理解这是因为没有fullx关系，但我想使用变量名来调用视图。

任何帮助都将是

Answer 1

您需要EXECUTE动态查询：

RETURN QUERY EXECUTE 'SELECT x FROM ' || fullx;

Answer 2

为select使用动态SQL（正如您用于create）：

create or replace function skyline_naive2(dataset text) returns setof integer as
$$
declare 
    fullx text;
begin
    fullx = dataset||'_skyline_naive2';
    execute format('create view %I as select x,y from %I',fullx,dataset);
    return query execute format('select x from %I', fullx);
end
$$ language plpgsql;

关系不存在PLPGSQL

2 个答案: