CREATE FUNCTION GET_STRING(@a1 int) RETURNS VARCHAR(50) AS BEGIN DECLARE @CLASS VARCHAR(50) SELECT @CLASS=ISNULL(@CLASS+'','')+a2 FROM a WHERE a1=@a1 order by a1 RETURN @CLASS END参考字符合并
select nid,title, cid=stuff((select ','+cid from class where n.nid=nid for xml path('')),1,1'') from news n
---------------------------------------------------------------- -- Author :SQL77(只为思齐老) -- Date :2010-01-08 19:42:18 -- Version: -- Microsoft SQL Server 2000 - 8.00.194 (Intel X86) -- Aug 6 2000 00:57:48 -- Copyright (c) 1988-2000 Microsoft Corporation -- Desktop Engine on Windows NT 5.1 (Build 2600: Service Pack 3) -- ---------------------------------------------------------------- --> 测试数据:[news] if object_id('[news]') is not null drop table [news] go create table [news]([nid] int,[title] varchar(3)) insert [news] select 2,'abc' union all select 3,'456' --> 测试数据:[class] if object_id('[class]') is not null drop table [class] go create table [class]([nid] int,[cid] int) insert [class] select 2,3 union all select 2,5 union all select 3,2 union all select 3,3 --------------开始查询-------------------------- ALTER FUNCTION GET_STRING(@nid int) RETURNS VARCHAR(50) AS BEGIN DECLARE @CLASS VARCHAR(50) SELECT @CLASS=ISNULL(@CLASS+',','')+LTRIM(cid) FROM class WHERE nid=@nid RETURN @CLASS END SELECT A.NID,B.CID,A.TITLE FROM NEWS A, ( SELECT NID,DBO.GET_STRING(NID)AS cid FROM class GROUP BY NID)AS B WHERE A.NID=B.NID ----------------结果---------------------------- /* NID CID TITLE ----------- -------------------------------------------------- ----- 2 3,5 abc 3 2,3 456(所影响的行数为 2 行) */
--sql 2000用如下函数实现,sql 2005参考后面的内容. create table [news]([nid] int,[title] varchar(3)) insert [news] select 2,'abc' union all select 3,'456' create table [class]([nid] int,[cid] int) insert [class] select 2,3 union all select 2,5 union all select 3,2 union all select 3,3 gocreate function dbo.f_str(@nid int) returns varchar(100) as begin declare @str varchar(1000) set @str = '' select @str = @str + ',' + cast(cid as varchar) from class where nid = @nid set @str = right(@str , len(@str) - 1) return @str end go--调用函数 select m.nid , isnull(n.cid,'') cid , m.title from news m left join (select nid , cid = dbo.f_str(nid) from class group by nid) n on m.nid = n.nid drop function dbo.f_str drop table news , class/* nid cid title ----------- ---------------------------------------------------------------------------------------------------- ----- 2 3,5 abc 3 2,3 456(所影响的行数为 2 行)*//* 标题:按某字段合并字符串之一(简单合并) 作者:爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 时间:2008-11-06 地点:广东深圳描述: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 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) as begin 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 @str end go--调用函数 select id , value = dbo.f_str(id) from tb group by iddrop function dbo.f_str drop table tb --2、sql2005中的方法 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 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') go declare @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 for select id , value from tb declare @id_old int , @id int , @value varchar(10) , @s varchar(100) open my_cursor fetch my_cursor into @id , @value select @id_old = @id , @s='' while @@FETCH_STATUS = 0 begin 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_cursorselect * from @t drop table tb
RETURNS VARCHAR(50)
AS
BEGIN
DECLARE @CLASS VARCHAR(50)
SELECT @CLASS=ISNULL(@CLASS+'','')+a2 FROM a WHERE a1=@a1 order by a1
RETURN @CLASS
END参考字符合并
cid=stuff((select ','+cid from class where n.nid=nid for xml path('')),1,1'')
from news n
-- Author :SQL77(只为思齐老)
-- Date :2010-01-08 19:42:18
-- Version:
-- Microsoft SQL Server 2000 - 8.00.194 (Intel X86)
-- Aug 6 2000 00:57:48
-- Copyright (c) 1988-2000 Microsoft Corporation
-- Desktop Engine on Windows NT 5.1 (Build 2600: Service Pack 3)
--
----------------------------------------------------------------
--> 测试数据:[news]
if object_id('[news]') is not null drop table [news]
go
create table [news]([nid] int,[title] varchar(3))
insert [news]
select 2,'abc' union all
select 3,'456'
--> 测试数据:[class]
if object_id('[class]') is not null drop table [class]
go
create table [class]([nid] int,[cid] int)
insert [class]
select 2,3 union all
select 2,5 union all
select 3,2 union all
select 3,3
--------------开始查询--------------------------
ALTER FUNCTION GET_STRING(@nid int)
RETURNS VARCHAR(50)
AS
BEGIN
DECLARE @CLASS VARCHAR(50)
SELECT @CLASS=ISNULL(@CLASS+',','')+LTRIM(cid) FROM class WHERE nid=@nid
RETURN @CLASS
END
SELECT A.NID,B.CID,A.TITLE FROM NEWS A,
(
SELECT NID,DBO.GET_STRING(NID)AS cid FROM class GROUP BY NID)AS B
WHERE A.NID=B.NID
----------------结果----------------------------
/*
NID CID TITLE
----------- -------------------------------------------------- -----
2 3,5 abc
3 2,3 456(所影响的行数为 2 行)
*/
create table [news]([nid] int,[title] varchar(3))
insert [news]
select 2,'abc' union all
select 3,'456'
create table [class]([nid] int,[cid] int)
insert [class]
select 2,3 union all
select 2,5 union all
select 3,2 union all
select 3,3
gocreate function dbo.f_str(@nid int) returns varchar(100)
as
begin
declare @str varchar(1000)
set @str = ''
select @str = @str + ',' + cast(cid as varchar) from class where nid = @nid
set @str = right(@str , len(@str) - 1)
return @str
end
go--调用函数
select m.nid , isnull(n.cid,'') cid , m.title from news m left join
(select nid , cid = dbo.f_str(nid) from class group by nid) n
on m.nid = n.nid
drop function dbo.f_str
drop table news , class/*
nid cid title
----------- ---------------------------------------------------------------------------------------------------- -----
2 3,5 abc
3 2,3 456(所影响的行数为 2 行)*//*
标题:按某字段合并字符串之一(简单合并)
作者:爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开)
时间:2008-11-06
地点:广东深圳描述: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
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)
as
begin
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 @str
end
go--调用函数
select id , value = dbo.f_str(id) from tb group by iddrop function dbo.f_str
drop table tb
--2、sql2005中的方法
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
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')
go
declare @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 for
select id , value from tb
declare @id_old int , @id int , @value varchar(10) , @s varchar(100)
open my_cursor
fetch my_cursor into @id , @value
select @id_old = @id , @s=''
while @@FETCH_STATUS = 0
begin
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_cursorselect * from @t
drop table tb