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linux(1) 题解(12)

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题解 | #话题的分布情况#

select substring_index (subject_set, ',', 1) subject_id1, -- 取出第一个数字 count(1) as cnt -- count(1)==count(*),后有group by，因此在这里count的subject_id1的次...

2024-07-14

2 155

题解 | #输出在5min内完成点击购买的用户ID#

-- trace_id为主键 select t1.user_id as uid from user_ad_click_time t1 join user_payment_time t2 on t1.trace_id = t2.trace_id where timestampdiff(minute...

2024-07-14

0 136

题解 | #查询用户刷题日期和下一次刷题日期#

select user_id, date , lead(date, 1, 'None') over(partition by user_id order by date) as nextdate from questions_pass_record

2024-07-14

0 131

题解 | #查询每天刷题通过数最多的前二名用户id和刷题数#

select t2.date, t2.user_id, t2.sum_pass_count as pass_count from (select t1.date, t1.user_id, t1.sum_pass_count, dense_rank() over (partition by t...

2024-07-14

0 141

题解 | #分群并计算群体人数#

select ( case when age < 20 then '20以下' when age between 20 and 50 then '20-50' when age > 50 then '50以上' else '未填写' en...

2024-07-14

0 121

题解 | #查询职位发布时间在2021年后或职位城市为上海

select job_id, boss_id, company_id from job_info where post_time >= '2021-01-01' or job_city = '上海'-- 要去重且排序，直接用or order by job_city

2024-07-14

0 118

题解 | #查询被投递过的职位信息#

select t2.* from deliver_record as t1 join job_info as t2 on t1.job_id = t2.job_id -- where t1.resume_if_checked = 1 -- order by -- t2....

2024-07-14

0 141

题解 | #查询2022年以来刷题用户的用user_id#

-- 查看数据类型，date类型可以用比较运算符 select user_id, university from user_info where user_id in (select user_id from questions_pass_record where date >= '2022-...

2024-07-14

0 128

题解 | #查询2022年毕业用户的刷题记录#

select * from questions_pass_record where user_id in (select user_id from user_info where graduation_year = '2022') -- 取出2022毕业的学号，遍历筛选

2024-07-14

0 133

vmware tools安装小结

左键虚拟机vmware tools为灰色关机，设置DVD（包括软盘）都为自动检测，开机，未进入系统前左键虚拟机安装vm tools，root进入。 vm tools正常 root进入，点击install vmware tools,出现vm tools安装包，后缀名.tar.gz，复制，打开文件...

2022-02-03

0 347