Oracle将两行合并为一行

Question

我计划将两(许多)行合并为一行.我的数据看起来像这样

??????????????????????????????????????????????????????????
? ReportID ?  Item  ? StartDt   ? EndDt     ? Statement  ?
??????????????????????????????????????????????????????????
?  1       ? 3000   ? 11-Mar-16 ? (null)    ? Remark     ?
??????????????????????????????????????????????????????????
?  1       ? 3001   ? 11-Mar-16 ? 13-Mar-16 ? (null)     ?
??????????????????????????????????????????????????????????
?  2       ? 4002   ? 24-May-16 ? 27-May-16 ? Remark1    ?
??????????????????????????????????????????????????????????
?  2       ? 4003   ? 24-May-16 ? 28-May-16 ? Remark1    ?
??????????????????????????????????????????????????????????

我很乐意合并ReportID并使用不同的规则:

• 使用最高 endDt
• 使用Statement不是null
• 使用Statement最高的记录Item

因此,结果应该是

?????????????????????????????????????????????????
? ReportID ? StartDt   ? EndDt     ? Statement  ?
?????????????????????????????????????????????????
?  1       ? 11-Mar-16 ? 13-Mar-16 ? Remark     ?
?????????????????????????????????????????????????
?  2       ? 24-May-16 ? 28-May-16 ? Remark1    ?
?????????????????????????????????????????????????

我需要使用纯SQL实现此功能,并且无法编写PL-SQL例程.

数据

SELECT 1 as ReportID, 3000 as Item, TO_DATE('11-03-2016') as StartDt, TO_DATE(NULL) as EndDt, 'Remark' as Statement FROM DUAL
UNION
SELECT 1, 3001, TO_DATE('11-03-2016'), TO_DATE('13-03-2016'), NULL FROM DUAL
UNION
SELECT 2, 4002, TO_DATE('24-05-2016'), TO_DATE('27-05-2016'), 'Remark1' FROM DUAL
UNION
SELECT 2, 4003, TO_DATE('24-05-2016'), TO_DATE('28-05-2016'), 'Remark1' FROM DUAL

Answer 1

你想要每行一行reportid,所以你要按它分组.然后使用适当的聚合函数(KEEP FIRST/LAST用于语句列)来获取所需的值:

select 
  reportid,
  max(startdt) as startdt,
  max(enddt) as enddt,
  max(statement) keep (dense_rank last 
                         order by case when statement is null then 1 else 2 end, item
                      ) as statement
from mytable
group by reportid
order by reportid;