select student.* from student join((select cid,max(score) max from scores group by cid) t1 join scores t2 where t1.cid=t2.cid) t3 where t3.sid=student.sid

这是一个 SQL 查询语句，目的是查询每个课程中得分最高的学生信息。具体实现方式是通过子查询找到每个课程的最高分数，然后再通过 join 操作将该课程的最高分数与学生表中的信息进行关联，最终得到每个课程中得分最高的学生信息。

相关问题

这个SQL改造一下，相同的省份可能超过一条时要根据和再计算。SELECT ranking FROM (SELECT PNAME, MAX(IPCOUNT) AS max_score, DENSE_RANK() OVER (ORDER BY MAX(IPCOUNT) DESC) AS ranking FROM T_FACT_CDN_PRO_COUNT WHERE QUARTER = '202301' GROUP BY PNAME) t1 WHERE t1.PNAME = '甘肃' ORDER BY ranking ASC;

如果相同省份可能有多条数据，需要将其求和并作为计算排名的依据。可以通过在内层查询中使用`SUM()`函数来实现。具体的SQL语句如下：

SELECT ranking
FROM (
    SELECT pname, MAX(score_sum) AS max_score, DENSE_RANK() OVER (ORDER BY MAX(score_sum) DESC) AS ranking
    FROM (
        SELECT pname, SUM(total_score) AS score_sum
        FROM scores
        WHERE exam_time = '202301'
        GROUP BY pname
    ) t
    GROUP BY pname
) t1
WHERE t1.pname = '甘肃'
ORDER BY ranking ASC;

其中，`scores`是存储成绩信息的表，包含以下字段：`pname`(省份名称)、`total_score`(总分)、`exam_time`(考试时间)。首先，在内层查询中使用`SUM()`函数计算每个省份的总分，并按照省份进行分组。然后，再在外层查询中使用`MAX()`函数和`DENSE_RANK()`函数计算出每个省份的最高总分和排名。最后，通过`WHERE`子句筛选出指定的省份，再按照排名升序排序。

select a.s_id ,a.s_name ,count(b.c_id) as sum_course ,sum(b.s_score)as sum_score from student a left join score b on a.s_id=b.s_id GROUP BY a.s_id,a.s_name

Sure! Here is the SQL query to fulfill your request:

SELECT a.s_id, a.s_name, COUNT(b.c_id) AS sum_course, SUM(b.s_score) AS sum_score
FROM student a
LEFT JOIN score b ON a.s_id = b.s_id
GROUP BY a.s_id, a.s_name;

This query will retrieve the student ID (`s_id`), student name (`s_name`), the total number of courses taken by each student (`sum_course`), and the sum of scores obtained by each student (`sum_score`). The `LEFT JOIN` ensures that all students are included in the result, even if they don't have any scores recorded in the `score` table.

Let me know if you need any further assistance!