对递增 1 的连续行进行分组

Question

这是我的数据：

FirstKey   SecondKey    Sequence
A1         B1           10001
A1         B1           10002
A1         B1           10003
A1         B1           10004
A1         B2           10001
A1         B2           10003
A1         B2           10005
A1         B3           10001
A1         B3           10002
A1         B3           10003
A2         B4           20001
A2         B5           20002
A2         B5           20003
A2         B6           20004

我尝试输出以下结果：

FirstKey   SecondKey    StartSequence EndSequence
A1         B1           10001         10004
A1         B2           10001         10001
A1         B2           10003         10003
A1         B2           10005         10005
A1         B3           10001         10003
A2         B4           20001         20001
A2         B5           20002         20003
A2         B6           20004         20004

序列是整数，不是 varchar。我希望使用相同键（FirstKey、SecondKey）彼此跟随的序列出现在同一行上。我的结果是按 FirstKey, SecondKey, Sequence 排序的有谁知道在 SQL 中输出这个的解决方案（我是运行 Sybase 12.5）

Answer 1

一个常见的解决方案是利用 ROW_NUMBER 以及序列中存在间隙的事实：

select FirstKey,
   SecondKey,
   min(Sequence),
   max(Sequence)
from 
 (
   select FirstKey,
      SecondKey,
      Sequence,
      -- meaningless value, but the same for sequential rows
      Sequence -
      row_number() over (partition by FirstKey, SecondKey order by Sequence) as grp 
   from tab
 ) dt
group by 
   FirstKey,
   SecondKey,
   grp

对递增 1 的连续行进行分组

Group consecutive rows that are incremented by 1

sql

sybase