select a as t1 from score where c_id=01
时间: 2024-02-24 09:54:37 浏览: 22
好的,这是查询课程id为01的成绩并将结果命名为t1的SQL语句:
```
SELECT a AS t1
FROM score
WHERE c_id = '01';
```
请注意,上述语句假设你的成绩表名为score,并且该表中包含c_id和a这两个字段。如果你的实际情况不同,请相应地修改语句中的表名和字段名。
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 t1.gname, t1.score, t1.pics FROM game t1 INNER JOIN ( SELECT tid, MAX(score) AS max_score FROM game WHERE score != '评分过少' GROUP BY tid ) t2 ON t1.tid = t2.tid AND t1.score = t2.max_score INNER JOIN gameType t3 ON t1.tid = t3.tid WHERE t3.tname IN ( SELECT tname FROM `user` u INNER JOIN stock s ON u.uid = s.uid INNER JOIN game g ON s.gid = g.gid INNER JOIN gameType t ON g.tid = t.tid WHERE u.uid = (SELECT uid FROM `user` WHERE uname = 'admin') GROUP BY tname ) ORDER BY t1.gid;将以上sql优化,使得查出来的数据,相同的tname只留最小的gid的那一个数据
以下是优化后的 SQL 查询语句:
```
SELECT t1.gname, t1.score, t1.pics
FROM game t1
INNER JOIN (
SELECT tid, MAX(score) AS max_score, MIN(gid) AS min_gid
FROM game
WHERE score != '评分过少'
GROUP BY tid
) t2 ON t1.tid = t2.tid AND t1.score = t2.max_score AND t1.gid = t2.min_gid
INNER JOIN gameType t3 ON t1.tid = t3.tid
WHERE t3.tname IN (
SELECT tname
FROM `user` u
INNER JOIN stock s ON u.uid = s.uid
INNER JOIN game g ON s.gid = g.gid
INNER JOIN gameType t ON g.tid = t.tid
WHERE u.uid = (SELECT uid FROM `user` WHERE uname = 'admin')
GROUP BY tname
)
ORDER BY t1.gid;
```
在优化后的查询语句中,我添加了一个子查询来获取每个 tid 对应的最小 gid,然后在主查询中加入条件 t1.gid = t2.min_gid 来确保只保留相同 tname 下的最小 gid 的数据。这样可以实现相同的 tname 只留下最小 gid 的要求。