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题解 | #分组过滤练习题#

1、HAVING select university, avg(question_cnt) as avg_question_cnt, avg(answer_cnt) as avg_answer_cnt from user_profile...

Mysql

2022-01-18

0 227

题解 | #计算男生人数以及平均GPA#

1、COUNT计数 AVG平均数 ROUND四舍五入（可控制几位小数） SELECT COUNT(gender) AS male_num, ROUND(avg(gpa),1) AS avg_gpa FROM user_profile WHERE&...

Mysql

2022-01-18

0 247

题解 | #查找某个年龄段的用户信息#

1.between列值之间 select device_id,gender,age from user_profile where age between 20 and 23 2.and条件连接 select&...

Mysql

2022-01-15

0 222

题解 | #查询结果去重#

1、distinct select distinct university from user_profile （distinct去重，放在列的前面使用） 2、group by select univers...

Mysql

2022-01-15

1 187