Sql 在组内比较以获取公共值

我有一张表，上面有以下数据

案例1：

table1
-------------
id      type
-------------
1         X
1         Y
2         X
3         Z
3         X
-------------

现在，正如您所看到的，X对于所有id都是公共的，所以在本例中，我需要返回X

案例2：

table1
-------------
id      type
-------------
1         X
1         Y
2         X
2         Y
3         X
3         Y
--------------

在这种情况下，X和Y都是公共的，然后我需要返回X和Y逗号分隔的X，Y

案例3

table1
-------------
id      type
-------------
1         X
1         Y
2         X
2         Y
3         X
3         Y
4         NULL
------------------

如果任何记录中出现null，我需要返回null

事实上，我告诉你的数据是从3个表中填充的，所以我已经为此编写了查询，但是现在我需要比较组中的公共数据组，这让我很困惑，如何比较组

注意：此处的组基于ID

---

任何帮助都将被告知

您可以将发生的事件与ID的计数进行比较吗

with data as (select rownum id, 'X' type from dual connect by level <= 3
              union all
              select rownum id, 'Y' type from dual connect by level <= 3
              union all
              select 3 id, 'Z' type from dual)
select wm_concat(distinct type)
  from (select type, count(*) over (partition by type) cnt, count(distinct id) over () total_ids
          from data)
 where cnt = total_ids;

而不是4，NULL，并且还希望返回NULL而不是分隔列表在这种情况下，您可以添加一个带有4的检查，上面的NULL将返回NULL，即使在以前的SQL版本上，因为计数不会占用：

       with data as (select rownum id, 'X' type from dual connect by level <= 3
                      union all
                      select rownum id, 'Y' type from dual connect by level <= 3
                      union all
                      select 3 id, 'Z' type from dual)
        select wm_concat(distinct type)
          from (select type, count(*) over (partition by type) cnt, count(distinct id) over 

() total_ids,
                       max(case when type is null then 'Y' else 'N' end) over () has_null_in_set
                  from data)
         where cnt = total_ids
          and has_null_in_set = 'N';

---

：不，您的编辑部分不是我的有效案例，但非常感谢您的精彩回答，非常感谢

       with data as (select rownum id, 'X' type from dual connect by level <= 3
                      union all
                      select rownum id, 'Y' type from dual connect by level <= 3
                      union all
                      select 3 id, 'Z' type from dual)
        select wm_concat(distinct type)
          from (select type, count(*) over (partition by type) cnt, count(distinct id) over 

() total_ids,
                       max(case when type is null then 'Y' else 'N' end) over () has_null_in_set
                  from data)
         where cnt = total_ids
          and has_null_in_set = 'N';