Question

我的桌子上有这些列：

id       country     
A        Italy
A        France
A        Germany
B        Italy
B        France
C        Italy
C        France

我想获取 id ，其中包含 ONLY 意大利和法国，因此结果将变成这样：

id  
B
C

感谢您的帮助

Answer 1

对我而言，最简单的方法是通过id进行汇总，然后断言最小的国家是法国，最大的国家是意大利：

SELECT id
FROM yourTable
GROUP BY id
HAVING MIN(country) = 'France' AND MAX(country) = 'Italy' AND
       COUNT(DISTINCT country) = 2;

Answer 2

您可以使用exists

尝试如下

     with cte as
(
select 'A' as id , 'Italy' as country union all
select 'A','France' union all
select 'A','Germany' union all
select 'B','Italy' union all
select 'B','France' union all
select 'C' ,'Italy' union all
select 'C','France' 

) select distinct id from cte t1
 where  exists ( select 1 from cte t2
  where t1.id=t2.id  
  having count(distinct country)=2
 )
 and country in ('France','Italy')

输出

id
B
C

demo fiddle

Answer 3

Postgres中更通用的方法是使用数组进行比较：

select id
from t
group by id
having array_agg(country order by country) = array['France', 'Italy'];

Here是db <>小提琴。

Answer 4

你为什么不使用这个

select distinct(id) 
        from countries
        where country in ('Italy','France');

PostgreSQL-过滤条件后计数

4 个答案: