Question

我有下表，其中描述了特定用户对特定对象的权限：

+------+-----------+----------+-----------+------------+------------+
| type | object_id | can_read | can_write | can_delete | can_create |
+------+-----------+----------+-----------+------------+------------+
|    0 |         1 |        1 |         1 |          0 |          1 |
|    0 |         2 |        1 |         0 |          0 |          0 |
|    1 |         1 |        1 |         1 |          1 |          0 |
+------+-----------+----------+-----------+------------+------------+

type和object_id是整数。

type是对象类型。存在共享相同object_id的不同类型的对象，但由于不同的＆＃34;类型＆＃34;应该被视为不同的对象。

can_read，can_write，can_delete，can_create是布尔值，它描述当前所选用户可以对（type，object_id）元组执行的操作。

此表是几个UNION的输出，它们既获取单个用户对object_id的权限，又获取特定＆＃34; Group＆＃34;的权限。 as object_id，其中单个用户是成员，然后为每个对象类型重复。

现在问题。我现在想要返回与type和object_id不同的行。对于任何重复记录，布尔值应该是逻辑＆＃34; OR＆＃34;在每一行。

在这种情况下，上面的示例表应该返回为：

arguments

在这种情况下，由于所选用户具有权限can_read = true，can_write = false，can_delete = false，can_create = true来自单个用户权限，类型= 0，object_id = 1。然后同一个用户拥有权限can_read = true，can_write = true，can_delete = false，can_create = false来自类型为0的组成员资格，object_id = 1.

因此有效权利是can_read = true，can_write = true，can_delete = false，can_create = true。

Answer 1

你可能需要一个聚合函数来合并这种情况下每个类型的最大值的值object_id

   select type, object_id
      , max(can_read) can_read
      , max(can_write) can_write
      , max(can_delete) can_delete
      , max(can_create) can_create
   from my_table 
   group by type, object_id

和联盟

   select type, object_id
      , max(can_read) can_read
      , max(can_write) can_write
      , max(can_delete) can_delete
      , max(can_create) can_create
   from (

    select type, object_id, can_read, can_write, can_delete, can_create
    from table1
    union 

    select type, object_id, can_read, can_write, can_delete, can_create
    from table2
   ) t
   group by type, object_id

Answer 2

如果1行为1则为1，如果为1则为0，则需要使用MAX（）函数：

SELECT type, object_id,
 MAX(can_read),
 MAX(can_write),
 MAX(can_delete),
 MAX(can_create)
FROM myTable
GROUP BY type, object_id

将SQL中的多个记录与每个布尔值的逻辑OR组合在一起

2 个答案: