1 /*
2 标题：按某字段合并字符串之一(简单合并)
3 作者：爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开)
4 时间：2008-11-06
5 地点：广东深圳
6
7 描述：将如下形式的数据按id字段合并value字段。
8 id value
9 ----- ------
10 1 aa
11 1 bb
12 2 aaa
13 2 bbb
14 2 ccc
15 需要得到结果：
16 id value
17 ------ -----------
18 1 aa,bb
19 2 aaa,bbb,ccc
20 即：group by id, 求 value 的和（字符串相加）
21 */
22 --1、sql2000中只能用自定义的函数解决
23 create table tb(id int, value varchar(10))
24 insert into tb values(1, 'aa')
25 insert into tb values(1, 'bb')
26 insert into tb values(2, 'aaa')
27 insert into tb values(2, 'bbb')
28 insert into tb values(2, 'ccc')
29 go
30
31 create function dbo.f_str(@id varchar(10)) returns varchar(1000)
32 as
33 begin
34 declare @str varchar(1000)
35 select @str = isnull(@str + ',' , '') + cast(value as varchar) from tb where id = @id
36 return @str
37 end
38 go
39
40 --调用函数
41 select id , value = dbo.f_str(id) from tb group by id
42
43 drop function dbo.f_str
44 drop table tb
45
46
47 --2、sql2005中的方法
48 create table tb(id int, value varchar(10))
49 insert into tb values(1, 'aa')
50 insert into tb values(1, 'bb')
51 insert into tb values(2, 'aaa')
52 insert into tb values(2, 'bbb')
53 insert into tb values(2, 'ccc')
54 go
55
56 select id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '')
57 from tb
58 group by id
59
60 drop table tb
61
62
63 --3、使用游标合并数据
64 create table tb(id int, value varchar(10))
65 insert into tb values(1, 'aa')
66 insert into tb values(1, 'bb')
67 insert into tb values(2, 'aaa')
68 insert into tb values(2, 'bbb')
69 insert into tb values(2, 'ccc')
70 go
71 declare @t table(id int,value varchar(100))--定义结果集表变量
72 --定义游标并进行合并处理
73 declare my_cursor cursor local for
74 select id , value from tb
75 declare @id_old int , @id int , @value varchar(10) , @s varchar(100)
76 open my_cursor
77 fetch my_cursor into @id , @value
78 select @id_old = @id , @s=''
79 while @@FETCH_STATUS = 0
80 begin
81 if @id = @id_old
82 select @s = @s + ',' + cast(@value as varchar)
83 else
84 begin
85 insert @t values(@id_old , stuff(@s,1,1,''))
86 select @s = ',' + cast(@value as varchar) , @id_old = @id
87 end
88 fetch my_cursor into @id , @value
89 END
90 insert @t values(@id_old , stuff(@s,1,1,''))
91 close my_cursor
92 deallocate my_cursor
93
94 select * from @t
95 drop table tb