对嵌套select中的列进行分组

我有一张桌子 table1 包含以下列:

id (INT)
label (VARCHAR)
value (INT)

我想检索 value 列,整个行中 价值 是最大的,是最低的行 价值 . 像这样:

{
    average: xxx,
    maxval: {
        id: x,
        label: x,
        value: x
    },
    minval: {
        id: x,
        label: x,
        value: x
    }
}

尝试使用以下查询:

SELECT 
AVG(a.value) AS average, 
b.*,
c.*
FROM table1 a
INNER JOIN table1 b ON ( b.value = (SELECT MAX(value) FROM table1 WHERE label = "el")) 
INNER JOIN table1 c ON ( c.value = (SELECT MIN(value) FROM table1 WHERE label = "el")) 
WHERE a.label = "el";

但这将返回单个级别中的所有字段,如:

{
    average,
    id,
    label,
    value,
    id,
    label,
    value
}

也尝试过:

SELECT 
AVG(a.value) AS average, 
(SELECT b.* FROM table1 b WHERE ( b.value = (SELECT MAX(value) FROM table1 WHERE label = "el"))) AS maxval,
(SELECT c.* FROM table1 c WHERE ( c.value = (SELECT MIN(value) FROM table1 WHERE label = "el"))) AS minval
FROM table1 a
WHERE a.label = "el";

最后一个给出了一个错误,因为我试图在多个列上使用一个别名。

使用MySQL5.5。