在 Postgres 中从多行到单列

Question

我正在通过具有只读访问权限的 pgAdmin 4 使用 Postgres 9.5，我正在尝试编写一个 select 查询来转换这种形式的数据：

+----------+-------------------+--------------------+----------------+
| username |      filters      |       groups       |     roles      |
+----------+-------------------+--------------------+----------------+
| kd24     | Khaled  <27607>   | V1                 | NewsStand User |
| kd24     | Khaled  <27607>   | V1                 | User           |
| kd24     | Khaled  <27607>   | Weekly KPIs        | NewsStand User |
| kd24     | Khaled  <27607>   | Detailed Sales     | User           |
| kd24     | Khaled  <27607>   | Qanz Monthly Group | User           |
| kd24     | Khaled  <27607>   | Detailed Sales     | NewsStand User |
| kd24     | Khaled  <27607>   | Qanz Monthly Group | NewsStand User |
| kd24     | Khaled  <27607>   | Weekly KPIs        | User           |
| kd24     | Khaled  <F_27607> | Weekly KPIs        | User           |
| kd24     | Khaled  <F_27607> | Weekly KPIs        | NewsStand User |
| kd24     | Khaled  <F_27607> | Qanz Monthly Group | NewsStand User |
| kd24     | Khaled  <F_27607> | Detailed Sales     | User           |
| kd24     | Khaled  <F_27607> | V1                 | User           |
| kd24     | Khaled  <F_27607> | Detailed Sales     | NewsStand User |
| kd24     | Khaled  <F_27607> | Qanz Monthly Group | User           |
| kd24     | Khaled  <F_27607> | V1                 | NewsStand User |
| kd24     | khaled.d          | Weekly KPIs        | User           |
| kd24     | khaled.d          | V1                 | NewsStand User |
| kd24     | khaled.d          | Detailed Sales     | NewsStand User |
| kd24     | khaled.d          | Qanz Monthly Group | NewsStand User |
| kd24     | khaled.d          | Weekly KPIs        | NewsStand User |
| kd24     | khaled.d          | V1                 | User           |
| kd24     | khaled.d          | Detailed Sales     | User           |
| kd24     | khaled.d          | Qanz Monthly Group | User           |
+----------+-------------------+--------------------+----------------+

到这个表格：

+----------+-----------------------------------------------+-----------------------------------------------------+---------------------+
| username |                    filters                    |                       groups                        |        roles        |
+----------+-----------------------------------------------+-----------------------------------------------------+---------------------+
| kd24     |  Khaled  <27607>, Khaled  <F_27607>,khaled.d  | V1, Weekly KPIs, Detailed Sales, Qanz Monthly Group | NewStand User, User |
+----------+-----------------------------------------------+-----------------------------------------------------+---------------------+

请注意列过滤器、组和角色中的值可能会更改。

是否有可以执行该操作的 postgres select 脚本？

非常感谢！

Answer 1

您可以使用 distinct 关键字和聚合函数，如 array_agg 从每一列收集不同的值：

select
    array_agg(distinct username) as username,
    array_agg(distinct filters) as filters,
    array_agg(distinct groups) as groups,
    array_agg(distinct roles) as groups
from YourTable;

Answer 2

试试这个

SELECT
    username,
    string_agg(DISTINCT filters,',') as filters,
    string_agg(DISTINCT groups,',') as roles,
    string_agg(DISTINCT roles,',') as groups
FROM
    table1
GROUP BY
    username;

Demo

在 Postgres 中从多行到单列

From multiple rows to single column in Postgres

sql

postgresql

string-aggregation