Postgres 中从多行到单列

Question

我通过 pgAdmin 4 使用具有只读访问权限的 Postgres 9.5，并且尝试编写一个选择查询来转换来自此表单的数据：

+----------+-------------------+--------------------+----------------+
| 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           |
+----------+-------------------+--------------------+----------------+

对于这种形式：

+----------+-----------------------------------------------+-----------------------------------------------------+---------------------+
| 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发生变化。

postgres select 脚本可以执行此操作吗？

非常感激！

Answer 1

尝试这个

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;

演示