标题：按某字段合并字符串之一(简单合并)
描述：将如下形式的数据按id字段合并value字段。
id value
----- ------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
需要得到结果：
id value
------ -----------
1 aa,bb
2 aaa,bbb,ccc
即：group by id, 求 value 的和（字符串相加）
1、sql2000中只能用自定义的函数解决
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create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2,'ccc')gocreate function dbo.f_str(@id int) returns varchar(100)asbegin declare @str varchar(1000) set @str='' select @str=@str+''+cast(value as varchar) from tb where id = @id set @str=right(@str , len(@str) - 1) return @strendgo--调用函数select id , value = dbo.f_str(id) from tb group by iddrop function dbo.f_strdrop table tb |
2、sql2005中的方法
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create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2, 'ccc')goselect id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '')from tb group by iddrop table tb |
3、使用游标合并数据
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create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2, 'ccc')godeclare @t table(id int,value varchar(100))--定义结果集表变量--定义游标并进行合并处理declare my_cursor cursor local forselect id , value from tbdeclare @id_old int , @id int , @value varchar(10) , @s varchar(100)open my_cursor fetch my_cursor into @id , @valueselect @id_old = @id , @s=''while @@FETCH_STATUS = 0begin if @id = @id_old select @s = @s + ',' + cast(@value as varchar) else begin insert @t values(@id_old , stuff(@s,1,1,'')) select @s = ',' + cast(@value as varchar) , @id_old = @id end fetch my_cursor into @id , @value END insert @t values(@id_old , stuff(@s,1,1,'')) close my_cursor deallocate my_cursor select * from @tdrop table tb |
以上就是关于分组字符合并SQL语句的介绍。希望对大家有所帮助。
