分组并过滤其他列上的2个不同值，其中必须包含1个值

Question

我有一张桌子T1

Jn company
X1 c1
X1 c2
X1 c3
Y2 c1
Y2 c2
Y2 c3
Z3 c2
Z3 c3
Z3 c4

我想按Jn分组，只过滤那些至少有2个独立公司的记录，其中1个应该是c1。

所需结果：

X1
Y2

我正尝试这样

select Jn from T1
group by Jn
having -----

Answer 1

select Jn
from your_table
group by Jn
having count(distinct company) >= 2 
   and sum(case when company = 'c1' then 1 else 0 end) > 0

Answer 2

使用聚合函数count()

    select Jn  from T1          
    group by jn
    having count(distinct company)>=2
    and sum(case when company='c1' then 1 else 0 end)>0

Answer 3

您可以使用exists：

select t1.Jn 
from table t1
where exists (select 1 from table t2 where t2.jn = t1.jn and t2.company = 'c1')

编辑：

select t1.Jn 
from table t1
group by jn
having count(distinct company) >= 2 and
       sum(case when company = 'c1' then 1 else 0 end) > 0;

Answer 4

这对您的测试数据对我有用。我得到所有拥有至少2个公司的Jns，然后将其与拥有C1公司的Jns相交

SELECT Jn
FROM T1
GROUP BY Jn
HAVING COUNT(Company) >= 2

INTERSECT

SELECT Jn
FROM T1
WHERE Company = 'c1'
GROUP BY Jn;