根据日期、记录列表中的活动选择 Oracle 中的最新记录答案

【问题标题】：SELECT the newest record in Oracle based on date, activity in the list of records根据日期、记录列表中的活动选择 Oracle 中的最新记录
【发布时间】：2015-09-06 23:55:00
【问题描述】：

我在其中一张表中有以下数据

我想根据突出显示的记录来区分它们，例如：当我根据Foreign_key列选择记录并且第二条记录是“Content = Response OR Process_id = 11”时 那么我需要将其标记为“PROCESS”。如果第二条记录不是 Content = Response 而是 "Content = Initiate OR Process_id = 20" (Foreign_key = 101) 那么我想标记它 "NOT过程”。

提示：此表中的活动是按 Processdate 顺序 (ASC) 创建的。

谁能建议我 SQL 查询，请记住，由于其他 JOIN 语句的负载，我需要在 CASE 内执行查询。

【问题讨论】：

标签： sql oracle subquery case .when

【解决方案1】：

Analytic functions 是你的救星

这里有一个完整的例子：

drop table test;
create table test
(id number,
content varchar2(30),
processdate date,
process_id number,
foreighn_key number);

insert into test values(1,'New',to_date('18.06.2015 10','dd.mm.yyyy hh24'), 10,100);
insert into test values(2,'Response',to_date('18.06.2015 11','dd.mm.yyyy hh24'), 11,100);
insert into test values(3,'Reply',to_date('18.06.2015 12','dd.mm.yyyy hh24'), 12,100);
insert into test values(4,'Closed',to_date('18.06.2015 13','dd.mm.yyyy hh24'), 13,100);
insert into test values(5,'New',to_date('18.06.2015 14','dd.mm.yyyy hh24'), 10,101);
insert into test values(6,'Initiate',to_date('18.06.2015 15','dd.mm.yyyy hh24'), 20,101);
insert into test values(7,'Target',to_date('18.06.2015 16','dd.mm.yyyy hh24'), 21,101);
insert into test values(8,'Closed',to_date('18.06.2015 17','dd.mm.yyyy hh24'), 13,101);
commit;

with trans as (
select ID, CONTENT, PROCESSDATE, PROCESS_ID, FOREIGHN_KEY,
-- first row per FK gets rn = 1
row_number() over (partition by FOREIGHN_KEY order by PROCESSDATE) rn,
-- lookup the next row value of the column
lead(CONTENT) over (partition by FOREIGHN_KEY order by PROCESSDATE) content_lead,
lead(PROCESS_ID) over (partition by FOREIGHN_KEY order by PROCESSDATE) Process_id_lead
from test order by processdate)
select 
 ID, CONTENT, PROCESSDATE, PROCESS_ID, FOREIGHN_KEY,
 case when content_lead = 'Response' OR Process_id_lead = 11 then 'PROCESS'
 when content_lead = 'Initiate' OR Process_id_lead = 20 then 'NOT PROCESS' end as trans_type
from trans 
where rn = 1

给予

    ID CONTENT                        PROCESSDATE         PROCESS_ID FOREIGHN_KEY TRANS_TYPE
---------- ------------------------------ ------------------- ---------- ------------ -----------
     1 New                            18.06.2015 10:00:00         10          100 PROCESS     
     5 New                            18.06.2015 14:00:00         10          101 NOT PROCESS

【讨论】：