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全部文章（共44篇）

题解 | #统计每种性别的人数#

# select if(profile like '%male','male','female') gender, # count(*) number # from user_submit # group by gender; # SELECT IF(profile LIKE '%female',...

2023-03-26

0 262

题解 | #计算用户8月每天的练题数量#

select day(date) as day, count(question_id) as question_cnt from question_practice_detail where month(date)=08 and year(date)=2021 group by date

2023-03-25

0 216

题解 | #查看不同年龄段的用户明细#

select device_id,gender, case when age<20 then "20岁以下" when age>=20 and age<=24 then "20-24岁" when age>=25 then "25岁及以上" el...

2023-03-25

0 238

题解 | #查找山东大学或者性别为男生的信息#

select device_id,gender,age,gpa from user_profile where university = "山东大学" union all select device_id,gender,age,gpa from user_profile where gender...

2023-03-25

0 194

题解 | #计算男生人数以及平均GPA#

select count(gender) as male_num, round(avg(gpa),1) as avg_gpa from user_profile where gender = "male"

2023-03-24

0 233

题解 | #查找GPA最高值#

select max(gpa) from user_profile where university = "复旦大学"

2023-03-24

0 227

题解 | #查看学校名称中含北京的用户#

select device_id,age,university from user_profile where university like "北京%"

2023-03-24

0 342

题解 | #操作符混合运用#

select device_id,gender,age,university,gpa from user_profile where (gpa>3.5 and university = "山东大学") or (gpa>3.8 and university = "复旦大学")

2023-03-24

0 241

题解 | #Where in 和Not in#

select device_id,gender,age,university,gpa from user_profile where university in ("北京大学","复旦大学","山东大学")

2023-03-24

0 192

题解 | #高级操作符练习(2）#

select device_id,gender,age,university,gpa from user_profile where university = "北京大学" or gpa > 3.7

2023-03-24

0 209