Question

下面是我的表（tracking_data）的示例数据的结构。我想在最后找到所有无法送达的包裹（cte_tracking_status_id = 10013）（有一些）。下面是一个包裹状态变化的例子。

CREATE TABLE tracking_data_event
(
    cte_id bigint NOT NULL DEFAULT nextval('tracking_data_event_cte_id_seq'::regclass),
    cte_tracking_number text NOT NULL,
    cte_tracking_status_id smallint NOT NULL,
    cte_timestamp timestamp without time zone,
    cte_description text,
    CONSTRAINT tracking_data_event_pkey PRIMARY KEY (cte_id)
)

Postgres版本：9.5

cte_id | cte_tracking_number | cte_tracking_status_id | cte_timestamp | cte_description  
--------------------------------------------------------------------------- 
8546809 | CO-141998094  |   1   | 19-04-2017 |  LABEL_PRINTED  
8708871 | CO-141998094  | 10014 | 19-04-2017 |    
9519695 | CO-141998094  | 10014 | 27-04-2017 |    
8708872 | CO-141998094  | 10004 | 27-04-2017 |  BPOST_LM_PARCEL_PROCESSED  
9519745 | CO-141998094  | 10014 | 27-04-2017 |    
8708933 | CO-141998094  | 10010 | 27-04-2017 |  BPOST_LM_PARCEL_STORED  
9519781 | CO-141998094  | 10014 | 27-04-2017 |    
8708969 | CO-141998094  | 10004 | 27-04-2017 |  BPOST_LM_PARCEL_PROCESSED  
8728290 | CO-141998094  | 10004 | 27-04-2017 |  BPOST_LM_TRANSIT  
8728291 | CO-141998094  | 10004 | 27-04-2017 |  BPOST_LM_TRANSIT  
9519829 | CO-141998094  | 10014 | 27-04-2017 |    
8728292 | CO-141998094  | 10004 | 27-04-2017 |  BPOST_LM_PARCEL_PROCESSED  
8743559 | CO-141998094  | 10004 | 28-04-2017 |  BPOST_LM_TRANSIT  
8743560 | CO-141998094  | 10004 | 28-04-2017 |  BPOST_LM_TRANSIT  
8767949 | CO-141998094  | 10009 | 01-05-2017 |  BPOST_LM_MISSED_DELIVERY  
9519855 | CO-141998094  | 10013 | 01-05-2017 |  BPOST_LM_UNDELIVERABLE  
8767950 | CO-141998094  | 10004 | 01-05-2017 |  BPOST_LM_TRANSIT  
8789169 | CO-141998094  | 20    | 02-05-2017 |  BPOST_LM_DELIVERED

Answer 1

如果“last”表示按时间戳排序的最后一个，那么您可以通过多种方式执行此操作。一种方法使用distinct on：

select t.*
from (select distinct on (cte_tracking_number) t.*
      from t
      order by cte_tracking_number, cte_timestamp desc
     ) t
where cte_tracking_status_id = 10013;

查找组中的最后一个事件

1 个答案: