MySQL : Don't show duplicate result on SELECT

Question

第三次选择显示结果与前两次选择重复的结果。 所以假设我的数据集只有 5 个 ID。 前两个语句产生 ids 1,2,3 enabled = 1 最后一条语句我需要 ids 4,5 enabled = 0

但现在我正在启用 ids 1,2,3,4,5 = 1 PLUS ids 1,2,3,4,5 enabled = 0

SELECT p.*, 1 as enabled
    FROM member_permissions mp
    JOIN permissions p ON p.permission_id = mp.permission_id
    WHERE member_id = 1
UNION
    SELECT pgp.*, 1 as enabled
    FROM member_permissions mp
    JOIN permission_link pl ON pl.permission_group_id = mp.permission_group_id
    JOIN permissions pgp ON pgp.permission_id = pl.permission_id
    WHERE member_id = 1
UNION
    SELECT *, 0 as enabled
    FROM permissions p

Answer 1

不幸的是，您必须对两个顶级查询执行两次才能将它们从较低的查询中删除:

SELECT p.*, 1 as enabled
    FROM member_permissions mp
    JOIN permissions p ON p.permission_id = mp.permission_id
    WHERE member_id = 1
UNION
    SELECT pgp.*, 1 as enabled
    FROM member_permissions mp
    JOIN permission_link pl ON pl.permission_group_id = mp.permission_group_id
    JOIN permissions pgp ON pgp.permission_id = pl.permission_id
    WHERE member_id = 1
UNION
    SELECT *, 0 as enabled
    FROM permissions p where p.permission_id not in (
      SELECT p.permission_id
          FROM member_permissions mp
          JOIN permissions p ON p.permission_id = mp.permission_id
          WHERE member_id = 1
      UNION ALL
      SELECT pgp.permission_id
          FROM member_permissions mp
          JOIN permission_link pl ON pl.permission_group_id = mp.permission_group_id
          JOIN permissions pgp ON pgp.permission_id = pl.permission_id
          WHERE member_id = 1
   )