Question

select s.attr1, s.attr2
from table1 s
where s.primarykey in 
    (select g.primarykey
    from table2 g
    group by g.primarykey
    having avg(g.numattr) > 80)
group by s.attr1
having min(s.attr3)
order by (s.attr2);

该查询应该在表2中检查平均numattr> 80，然后为满足该条件的主键，为每个attr1选择attr3的最小值，然后按attr2的顺序对其进行排序。我得到的结果是没有选择最小值，也不确定为什么。

Answer 1

您需要将MIN移至SELECT才能将其放入结果中。另外，您需要按attr1和attr2进行分组。您可以尝试以下方法吗？

SELECT s.attr1, s.attr2, min(s.attr3)
FROM table1 s
WHERE s.primarykey IN
    (SELECT g.primarykey
    FROM table2 g
    GROUP BY g.primarykey
    HAVING avg(g.numattr) > 80)
GROUP BY s.attr1, s.attr2
ORDER BY s.attr2;

Answer 2

SELECT s.attr1, s.attr2, 
FROM table1 s
WHERE s.attr3 = 
(SELECT min(s2.attr3) from table1 s2 where s.attr1 = s2.attr1 group by s2.attr1)
and s.primarykey IN
(SELECT g.primarykey
FROM table2 g
GROUP BY g.primarykey
HAVING avg(g.numattr) > 80)
GROUP BY s.attr1, s.attr2
ORDER BY s.attr2;

我认为是这样做的。

SQL查询分组依据，是否具有最小值，而不是选择最小值？

2 个答案: