如何摆脱多个branch_id？

Question

我有一个这样的 SQL 查询：

SELECT 
    COUNT(PERMISSION_ID) AS USER_TOTAL_PERMISSION_PER_BRANCH,
    USER_ID,
    BRANCH_ID
FROM BRANCH_PERMISSION_USER
GROUP BY USER_ID, BRANCH_ID
ORDER BY USER_ID, USER_TOTAL_PERMISSION_PER_BRANCH DESC

但我有一个问题，因为我只想要每个 user_id 的第一行。主要目标是将用户列表放在它的分支和前 1 或 USER_TOTAL_PERMISSION_PER_BRANCH 上的不同

这是示例输出：

预期的输出应该是：

[USER_TOTAL_PERMISSION_PER_BRANCH][USER_ID][BRANCH_ID]

135    1    1
135    2    1
134    3    1
1      4    1
1      5    1
1      6    1

Answer 1

你可以使用窗口函数：

SELECT USER_TOTAL_PERMISSION_PER_BRANCH, USER_ID, BRANCH_ID
FROM (SELECT COUNT(*) AS USER_TOTAL_PERMISSION_PER_BRANCH,
             USER_ID, BRANCH_ID,
             ROW_NUMBER() OVER (PARTITION BY USER_ID ORDER BY COUNT(*) DESC) as seqnum
      FROM BRANCH_PERMISSION_USER
      GROUP BY USER_ID, BRANCH_ID
     ) ub
WHERE seqnum = 1

Answer 2

您可以将查询转换为 CTE，并使用相关性进行过滤：

with cte as (
    select 
        count(permission_id) as user_total_permission_per_branch,
        user_id,
        branch_id
    from branch_permission_user
    group by user_id, branch_id
)
select c.* 
from cte c
where c.user_total_permission_per_branch = (
    select max(c1.user_total_permission_per_branch)
    from cte c1 
    where c1.user_id = c.user_id and c1.branch_id = c.branch_id
)

Answer 3

感谢@Gordon 爵士

我使用他的逻辑。就是这样：

SELECT USER_TOTAL_PERMISSION_PER_BRANCH, USER_ID, BRANCH_ID
FROM (SELECT COUNT(*) AS USER_TOTAL_PERMISSION_PER_BRANCH,
             USER_ID, BRANCH_ID,
             ROW_NUMBER() OVER (PARTITION BY USER_ID ORDER BY COUNT(*) DESC) as seqnum
      FROM BRANCH_PERMISSION_USER
      GROUP BY USER_ID, BRANCH_ID
     ) ub
WHERE seqnum = 1