SELECT stu_no FROM student_course WHERE course_no IN (SELECT course_no FROM student_course WHERE stu_no=01
2023-07-10 09:03
133
0
0
0
```
SELECT s.name AS 姓名, c.name AS 课程名称, s.score AS 成绩, AVG(s.score) AS 平均成绩
FROM student s, course c
WHERE
2023-07-11 10:49
133
0
0
0
Student(S#,Sname,Sage,Ssex) 学生表Course(C#,Cname,T#) 课程表SC(S#,C#,score) 成绩表Teacher(T#,Tname) 教师表问题：1、查询“001”课程
2021-12-07 14:35
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1
1
0
SELECT student_num,student_name FROM student_score WHERE course_score
2023-07-10 09:02
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0
0
0
```
SELECT stu_name,score_sum,
@curRank := @curRank + 1 AS rank
FROM student,(SELECT @curRank := 0) r
ORDE
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132
0
0
0
SELECT student_name, course_name,score FROM student_course WHERE score>70;
2023-07-13 09:14
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0
0
0
SELECT sno,AVG(score)
FROM student
WHERE score < 60
GROUP BY sno
HAVING COUNT(score)>=2;
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0
0
0
1、减少不必要的数据库操作：尽量将多次查询合并成一次查询，使用存储过程，将多次查询合并成一次查询，减少数据库的操作次数。
2、优化SQL语句：可以在SQL语句中使用表的别名，加快查询速度；使用EXPLAIN关键
2023-07-07 09:21
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0
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0