题解 | #查询被投递过的职位信息#

题目出的有问题，实际上应该是 select * 选择第二个表格就能过关，不过对于强迫症是万万不行的；这里面其实是筛选被看过的简历，也就是resume_if_checked=1，然后按照company_id,进行重组。
答案1：
select company_id,sum(resume_if_checked)  cnt
from
    deliver_record d1,
    job_info j1
where
    d1.job_id = j1.job_id 
    group by company_id
    having cnt<>0
    order by company_id
	第一个解法用到了having，我们也可以不用having
答案2：
select   company_id,count(resume_id)  cnt
from
    deliver_record d1,
    job_info j1
where
    d1.job_id = j1.job_id
    and resume_if_checked=1
    group by company_id
    order by company_id