從Postgres中的多行到單列

Question

我正在通過具有只讀訪問權限的pgAdmin 4使用Postgres 9.5，我正在嘗試編寫一個select查詢，該查詢將從這種形式轉換數據：

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

填寫此表格：

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

注意列過濾器，組和角色中的值可能會更改。

是一個可以執行該操作的postgres選擇腳本？

非常感激！

Answer 1

您可以使用與諸如array_agg之類的聚合函數一起使用distinct關鍵字，以從每一列中收集不同的值：

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

嘗試這個

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