Question

基本上我想要

Select * from x 
JOIN y
on x.id = y.x_id
where y.tag_id in (1, 2, 3, 4) order by [the amount of hits of y.tag_id]

所以

说y可以是：

id | x_id | tag_id
1 | 55 | 2
2 | 55 | 3
3 | 66 | 1

我想让记录x.id = 55排序在x.id = 66之上.55有2次点击（2和3）而66只有一次点击

Answer 1

您可以在子查询中找到每个x_id的命中数，将其与X表连接，并按计算的数量对结果进行排序。

Select * from x 
JOIN y
on x.id = y.x_id
inner join (
    select x_id, count(*) cnt
    from y
    group x_id
) t on x.id = t.x_id
where y.tag_id in (1, 2, 3, 4)
order by t.cnt desc;

Answer 2

计算与传递的accuracy = accuracy_score(y_test, y_pred) Traceback (most recent call last): File "<ipython-input-263-232dbb7449ea>", line 1, in <module> accuracy = accuracy_score(y_test, y_pred) File "C:\Anaconda3\lib\site-packages\sklearn\metrics\classification.py", line 172, in accuracy_score y_type, y_true, y_pred = _check_targets(y_true, y_pred) File "C:\Anaconda3\lib\site-packages\sklearn\metrics\classification.py", line 82, in _check_targets "".format(type_true, type_pred)) ValueError: Can't handle mix of multilabel-indicator and continuous- multioutput匹配的x_id并在tag_id中使用

Order by

在计数时应用过滤器很重要，因为我们需要计算匹配的SELECT * FROM x JOIN y ON x.id = y.x_id JOIN (SELECT x_id, Count(*) hit_cnt FROM y WHERE y.tag_id IN ( 1, 2, 3, 4 ) GROUP BY x_id) ct ON ct.x_id = y.x_id ORDER BY hit_cnt DESC的{{1}}

订单记录＆＃34;在数组＆＃34;

2 个答案: