求一sql语句 - MS-SQL Server / 基础类

表
id bh  
1 10
2 11
3 12 
4 15
5 16
6 22
7 25
8 26
9 27
10 28

将bh按连续分段出来返回字符串：
10~12，15~16，22，25~28

---

SQL code:




declare @t table(num int)
insert into @t select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 12
union all select 17
union all select 18
union all select 19
union all select 20
union all select 25

select
rtrim(a.num)+(case when min(b.num)!=a.num then '-'+rtrim(min(b.num)) else '' end)
from
(select t.num from @t t where not exists(select 1 from @t where num=t.num-1)) a,
(select t.num from @t t where not exists(select 1 from @t where num=t.num+1)) b
where
a.num<=b.num
group by a.num

-------------------------
1-5
12
17-20
25
*/

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