使用窗口函数而不是聚合函数：

SELECT *, 
       MIN(value) OVER (PARTITION BY item) min_val, 
       MAX(value) OVER (PARTITION BY item) max_val 
FROM ask;

请参阅demo。

你不应该这样做。最有可能的是，您应该保持表的原样，而创建一个视图：

CREATE VIEW ask_minmax AS (
    SELECT item,
           max(value) AS maxval,
           min(value) AS minval
    FROM ask
    GROUP BY item
);

将CREATE TABLE中的第一个文本数据类型更改为varchar

CREATE TABLE ask (
item VARCHAR,
value Integer NOT NULL)

插入您的数据

INSERT INTO ask (item,value)
VALUES
('A',   1),
('A',   4),
('A',   3),
('B',   0),
('B',   1),
('C',   2),
('C', 4);

然后，在运行以下查询之后

With T1 As
(SELECT  item,max(value) as max_val, min(value) as min_val FROM ask
GROUP bY item)
Select T2.item,T2.value,T1.min_val,T1.max_val From ask T2
join T1 On T1.item = T2.item

您可以创建一个具有最大/最小值的临时表，然后将其联接以创建所需的表/结果。
即。

select item, max(value) maxval, min(value) minval
from ask group by item;

然后

SELECT a.item, a.value, maxval, minval
from 
  ask a
join
  (select item, max(value) maxval, min(value) minval from ask group by item) b
on a.item = b.item;