如何在oracle sql中对一系列数字进行分组，并提供特定的数字

我在oracle表中以以下格式存储了一系列数字

Emp_ID
1
2
3
4
5
6
7
8
9
10
14
15
16
17
18
31
32
33
34
35
36
41
42

我希望将此列表按固定数字（如7）分组，并以以下格式获得输出：

Range         Total
1-7            7
8-10,14-17     7
18-18,31-36    7
41-42          2

---

如果需要如示例所示的范围表示：

-- test data
with data(empid) as
 ( -- complete list 1..42
  select level
    from dual
  connect by level <= 42
  minus (
         -- minus gaps
         select level
           from dual
          where level between 11 and 13
         connect by level <= 42
         union
         select level
           from dual
          where level between 19 and 30
         connect by level <= 42
         union
         select level
           from dual
          where level between 37 and 40
         connect by level <= 42))

-- select:  
select listagg(case
                 when minempid = maxempid then
                  minempid || ' '
                 else
                  (minempid || '-' || maxempid)
               end,
               ', ') within group(order by minempid),
       sum(cnt)
  from (select grp,
               seq,
               min(empid) as minempid,
               max(empid) as maxempid,
               count(*) cnt
          from (select empid, rn, empid - rn as seq, ceil(rn / 7) as grp
                  from (select empid, row_number() over(order by empid) rn
                          from data))
         group by grp, seq)
 group by grp;

---

在Oracle 11g中，您可以使用listagg和分析函数：

---

另一个例子是使用case确定每个值的范围以及该范围上的分组：

select rng, count(1) from (
  select 
    case  
      when emp_id between 1 and 7 then 'range 1'
      when emp_id between 8 and 10 or emp_id between 14 and 17 then 'range 2'
      when emp_id between 18 and 18 or  emp_id between 31 and 36 then 'range 3'
      when emp_id between 41 and 42 then 'range 4'
      else 'no range'
    end as rng
  from employees) 
group by rng;

---

按行数猜组/7

select rng, count(1) from (
  select 
    case  
      when emp_id between 1 and 7 then 'range 1'
      when emp_id between 8 and 10 or emp_id between 14 and 17 then 'range 2'
      when emp_id between 18 and 18 or  emp_id between 31 and 36 then 'range 3'
      when emp_id between 41 and 42 then 'range 4'
      else 'no range'
    end as rng
  from employees) 
group by rng;