我需要加入以下2个表格，结果如下 这个数据基本上是2个表，它们通过某种类型的组从两个表上的多个键上连接起来，但是我正在绘制一个空白，如何实现这一点 我正在使用Oracle数据库。
感谢
<table border="0">
<tr><td><b>Table 1</b></td><td></td><td><b>Table 2</b></td></tr>
<tr>
<td>
<table border="1">
<tr>
<th>Group</th>
<th>Key</th>
</tr>
<tr>
<td>A</td>
<td>1</td>
</tr>
<tr>
<td>A</td>
<td>2</td>
</tr>
<tr>
<td>B</td>
<td>1</td>
</tr>
<tr>
<td>B</td>
<td>3</td>
</tr>
<tr>
<td>C</td>
<td>1</td>
</tr>
<tr>
<td>C</td>
<td>2</td>
</tr>
<tr>
<td>C</td>
<td>3</td>
</tr>
<tr>
<td>D</td>
<td>2</td>
</tr>
<tr>
<td>D</td>
<td>4</td>
</tr>
</table>
</td>
<td>
</td>
<td>
<table border="1">
<tr>
<th>Users</th>
<th>Key</th>
</tr>
<tr>
<td>U1</td>
<td>1</td>
</tr>
<tr>
<td>U2</td>
<td>1</td>
</tr>
<tr>
<td>U2</td>
<td>3</td>
</tr>
<tr>
<td>U3</td>
<td>1</td>
</tr>
<tr>
<td>U3</td>
<td>2</td>
</tr>
<tr>
<td>U3</td>
<td>4</td>
</tr>
<tr>
<td>U4</td>
<td>1</td>
</tr>
<tr>
<td>U4</td>
<td>2</td>
</tr>
<tr>
<td>U4</td>
<td>3</td>
</tr>
<tr>
<td>U4</td>
<td>4</td>
</tr>
<tr>
<td>U5</td>
<td>1</td>
</tr>
<tr>
<td>U5</td>
<td>2</td>
</tr>
<tr>
<td>U5</td>
<td>4</td>
</tr>
</table>
</td>
</tr>
<tr>
<td><b>RESULT</b></td>
</tr>
<tr>
<td>
<table border="1">
<tr>
<th>Users</th>
<th>Groups</th>
</tr>
<tr><td>U1</td><td></td></tr>
<tr><td>U2</td><td>B</td></tr>
<tr><td>U3</td><td>A</td></tr>
<tr><td>U4</td><td>A, B, C, D</td></tr>
<tr><td>U5</td><td>A, D</td></tr>
</table>
</td>
</tr>
</table>
答案 0 :(得分：1)
这是一种方式：
with grps as (select 'A' grp, 1 key from dual union all
select 'A' grp, 2 key from dual union all
select 'B' grp, 1 key from dual union all
select 'B' grp, 3 key from dual union all
select 'C' grp, 1 key from dual union all
select 'C' grp, 2 key from dual union all
select 'C' grp, 3 key from dual union all
select 'D' grp, 2 key from dual union all
select 'D' grp, 4 key from dual),
usrs as (select 'U1' usr, 1 key from dual union all
select 'U2' usr, 1 key from dual union all
select 'U2' usr, 3 key from dual union all
select 'U3' usr, 1 key from dual union all
select 'U3' usr, 2 key from dual union all
select 'U4' usr, 1 key from dual union all
select 'U4' usr, 2 key from dual union all
select 'U4' usr, 3 key from dual union all
select 'U4' usr, 4 key from dual union all
select 'U5' usr, 1 key from dual union all
select 'U5' usr, 2 key from dual union all
select 'U5' usr, 4 key from dual)
-- end of mimicking your tables; see SQL below
select usr,
listagg(case when usr_grp_cnt = grp_cnt then grp end, ', ') within group (order by grp) grps
from (select u.usr,
g.grp,
g.grp_cnt,
count(g.key) usr_grp_cnt
from usrs u
left outer join (select grp,
key,
count(*) over (partition by grp) grp_cnt
from grps) g on (g.key = u.key)
group by u.usr,
g.grp,
g.grp_cnt)
group by usr;
USR GRPS
--- ---------------
U1
U2 B
U3 A
U4 A, B, C, D
U5 A, D
这首先找到每个组的键数（假设它是唯一的），然后它对usrs“table”进行外连接（这里，它是WITH子句中定义的子查询; google如果您不熟悉子查询因子。您可能有一个与该子查询等效的表，所以您只需在主sql语句中使用它。）
接下来，我们通过检查用户+组密钥计数与组密钥计数是否相同来找到每个用户每组的密钥数，然后我们可以使用它计算出哪些组匹配。然后我们使用listagg函数将其聚合到一个列表中。
N.B。我不得不更改用户U3的数据，因为最初，您的数据具有与用户U5相同的密钥。