SQL 服务器：使用递归 CTE 解析组成员资格

Question

我有一个 table (users_groups) :

+-----------+------------+---------+
| groupGUID | memberGUID | isGroup |
+-----------+------------+---------+
|  32AB160C |   5B277276 |       0 |
|  32AB160C |   0A023D1D |       0 |
|  5C952B2E |   32AB160C |       1 |
|  4444FTG5 |   5C952B2E |       1 |
+-----------+------------+---------+

isGroup列表示memberGUID是否为一个组。

我想获得一个新的 table (new_users_groups)，所有组成员资格都已解决：

+-----------+------------+
| groupGUID | memberGUID |
+-----------+------------+
|  32AB160C |   5B277276 |
|  32AB160C |   0A023D1D |
|  5C952B2E |   5B277276 |
|  5C952B2E |   0A023D1D |
|  4444FTG5 |   5B277276 |
|  4444FTG5 |   0A023D1D |
+-----------+------------+

目前，我正在手动执行所有操作：

正在寻找所有组的成员GUID

SELECT * FROM users_groups WHERE isGroup = 1;
对于上一步返回的所有组，找到其成员

SELECT * FROM users_groups WHERE groupGUID = '5C952B2E'
如果成员不是群组，将他们插入到新的 table

INSERT INTO new_users_groups (groupGUID, memberGUID) VALUES ('5C952B2E', '5B277276'); INSERT INTO new_users_groups (groupGUID, memberGUID) VALUES ('5C952B2E', '0A023D1D');
如果成员是组，转到步骤 2。

我怎样才能使它自动化？也许使用递归 CTE？

Answer 1

您可以使用递归 CTE 执行此操作：

with cte as (
  select ug.groupGUID, ug.groupGUID as grp, ug.memberGUID
  from user_groups ug
  where isGroup = 0
  union all
  select ug.groupGUID, ug.groupGUID as grp, cte.memberGUID
  from user_groups ug join
       cte
       on cte.grp = ug.memberGUID
 )
select groupGUID, memberGUID
from cte;

这里是Rextester.

Answer 2

尝试CROSS JOIN

SELECT t1.groupGUID, t2.memberGUID 
FROM temp t1, temp t2 WHERE t2.isGroup = 0
GROUP BY t1.groupGUID, t2.memberGUID

SQL 服务器：使用递归 CTE 解析组成员资格

SQL Server : Using recursive CTE to resolve group membership

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