postgreSQL-总小时数（通过唯一ID等）

Question

我正在尝试找出如何通过唯一ID（每个ID仅表示一个）来求和时间。这是一些数据的标记。我需要GROUP BY f_name，l_name和area。我还需要组计数（唯一编号的id）和组参与者（仅简单编号的id）。

+----+------+-------+-------+------+--+
| ID | Time | fname | lname | Area |  |
+----+------+-------+-------+------+--+
|  1 | 3:30 | Jeff  | Chose | LA   |  |
|  1 | 3:30 | Jeff  | Chose | LA   |  |
|  1 | 3:30 | Jeff  | Chose | LA   |  |
|  2 | 4:00 | Jeff  | Chose | LA   |  |
+----+------+-------+-------+------+--+

数据应如下所示：

+------+-------+-------+------+-------------+--------------------+
| Time | fname | lnam  | Area | Group Count | Group Participants |
+------+-------+-------+------+-------------+--------------------+
| 7:30 | Jeff  | Chose | LA   |           2 |                  4 |
|      |       |       |      |             |                    |
+------+-------+-------+------+-------------+--------------------+

奖金：如果您可以将3:30转换为3.5

Answer 1

SQL DEMO

WITH cte as (
    SELECT fname, lname, Area,
           COUNT(DISTINCT id) as "Group Count",
           COUNT(id) as "Group Participants", 
           SUM(DISTINCT "time"::time) as "Time"
    FROM Table1
    GROUP BY fname, lname, Area, id 
)    
SELECT fname, lname, Area,
       SUM("Group Count") as "Group Count",
       SUM("Group Participants") as "Group Participants", 
       SUM("Time"::time) as "Time"
FROM cte
GROUP BY fname, lname, Area;

输出