MySQL - 在选择另一列的最小值后选择一列的最小值

Question

我有下表(tablea):

       x            y
---------------------------
      3            1 
      1            4
      1            3

结果我想要 x = 1 和 y = 3(让 x 尽可能低是最高优先级，让 y 尽可能低是次要优先级)。 所以我想要一个类似这样的 SQL 语句:

Select Min(y), x 
FROM (SELECT MIN(x), y FROM tablea);

但这给了我以下错误代码:

Error Code: 1248. Every derived table must have its own alias

如果我尝试这样做:

Select Min(y), x 
FROM (SELECT MIN(x), y FROM tablea) as a;

我得到:

Error Code: 1054. Unknown column 'x' in 'field list'

Answer 1

为避免错误未知列，您需要将别名添加到MIN(x):

Select Min(a.y), a.x 
FROM (SELECT MIN(x) AS x, y FROM tablea) as a;

但为了获得您建议的结果，我会将您的查询重写为:

Select x, MIN(y) AS y
FROM tablea
WHERE x = (SELECT MIN(x) FROM tablea);

SqlFiddleDemo