Laravel Postgres计算时差并获得最小值/最大值

Question

我的表结构是这样的，我正在使用laravel和postgres数据库

id | serving_start_time      | serving_end_time    
1  | 2016-10-05 00:24:08.894 | 2016-10-05 00:24:19.003    
2  | 2016-10-05 00:24:59.875 | 2016-10-05 00:25:13.728    
3  | 2016-10-05 11:43:52.055 | 2016-10-05 11:45:41.561

我想计算＆＃39; total_serving_time＆＃39;（serving_start_time-serving_end_time）并且只获得最小和最大的total_serving_time＆＃39;。这可能在一个查询中？请帮忙

Answer 1

在一个如下的查询中？

SELECT 
    MIN(serving_end_time - serving_start_time) AS min_total_serving_time,
    MAX(serving_end_time - serving_start_time) AS max_total_serving_time
FROM table;