Question

我想获得特定值的最小值，和具有该最小值的行的键。目前，我这样做如下：

SELECT dates.date AS Date, num_apples.apples AS MinApples FROM
(
    SELECT date, MIN(apples) AS MinApples, apples
    FROM Table
    HAVING MinApples = apples
) AS dates
JOIN
(
    SELECT date, apples
    FROM Table
) AS num_apples
ON (
    dates.date = num_apples.date
);

有没有更好的方法只使用“标准”（我指的是通常实现的）SQL？

Answer 1

这是ANSI标准SQL：

select *
from (
  select date, 
         apples, 
         min(apples) over () as min_apples
  from the_table
) t
where apples = min_apples;

窗口函数可用于各种DBMS。

Answer 2

假设date是你的关键：

SELECT qryNumApples.* FROM
(
    SELECT MIN(apples) AS MinApples
    FROM Table
) AS qryMinApples
JOIN
(
    SELECT *
    FROM Table
) AS qryNumApples
ON qryMinApples.MinApples= qryNumApples.apples
);

Answer 3

我总是这样做：

SELECT *
FROM the_table
WHERE apples = (SELECT MIN(apples) 
                  FROM the_table);

但也许我错过了什么。

我可以在单个查询中获取与聚合相关的数据吗？

3 个答案: