第一个和最后一个值 ORACLE

Question

尝试在 Oracle 8i 中获得此输出：

    column1 |time
    ________|_______
      ABC   | 00:00:01
      END   | 00:00:03
      123   | 00:00:04
      END   | 00:00:07

来自另一个查询的输出

   column1 |time
    ________|_______
      ABC   | 00:00:01
      ABC   | 00:00:02
      ABC   | 00:00:03
      123   | 00:00:04
      123   | 00:00:05
      123   | 00:00:06
      123   | 00:00:07

我可以在这里使用“first”或“last”的任何命令吗[比如在 XPath 中]？尝试 GROUP BY 但它不能正常工作:(

谢谢！

Answer 1

您可以将其放在两列中，这将是更自然的方法：

select column1, min(time) as firsttime, max(time) as lasttime
from t
group by column1;

你真的想要四行输出，END 在两行上不知道结束的内容吗？

编辑：

要得到你想要的输出：

select (case when n.n = 1 then column1 else 'END' end) as column1,
       (case when n.n = 1 then firsttime else lasttime end) as "time"
from (select column1, min(time) as firsttime, max(time) as lasttime
      from t
      group by column1
     ) t cross join
     (select 1 as n from dual union all select 2 from dual) n
order by column1, n.n;

注意order by 子句。结果不保证按任何特定顺序排列，排序对于理解这些结果很重要。