Question

我有一张桌子（users_groups）：

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

isGroup列指示memberGUID是否为组。

我想获取一个新的表（new_users_groups），其中所有组成员身份都已解决：

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

目前，我正在手动进行所有操作：

正在寻找所有组的memberGUID

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'
如果成员不是组，则将其插入新表中

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，请转到步骤2。

我该如何自动化？也许使用递归CTE？

Answer 1

您可以使用递归CTE来做到这一点：

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 Server：使用递归CTE来解决组成员身份

2 个答案: