```
select stu_id,stu_name,AVG(score) from student inner join score on student.stu_id=score.stu_id where sco
2023-07-11 10:47
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sql找出连续7天登陆，连续30天登陆的用户
要找出连续7天登录和连续30天登录的用户，你可以使用SQL查询来实现。请注意，具体的查询语法可能因使用的数据库管理系统而有所不同。以下是一种通用的示例查询：
2023-06-13 19:54
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SELECT t1.name, t1.grade
FROM table1 t1
INNER JOIN
(
SELECT class, MAX(grade) AS max_grade
FRO
2023-07-15 08:48
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select distinct student_id
from student_course
group by student_id
having count(*) >= 2;
2023-07-16 09:34
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```
SELECT a.name,a.chinese,a.math,a.english,
(SELECT COUNT(*)
FROM Table b
WHERE b.chinese > a.ch
2023-07-09 09:08
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```
SELECT student_name,AVG(grade) as avg_grade,(SELECT COUNT(DISTINCT(AVG(grade))) FROM student_grade WHERE
2023-07-12 15:20
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1、为已有表添加索引：
ALTER TABLE `table_name`
ADD INDEX `index_name` (`column_1`, `column_2`, ...);
2、为已有表添加唯一索引
2023-07-05 09:11
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