SQL code问题描述: 无论是在sql 2000,还是在 sql 2005 中,都没有提供字符串的聚合函数, 所以,当我们在处理下列要求时,会比较麻烦: 有表tb, 如下: id value ----- ------ 1 aa 1 bb 2 aaa 2 bbb 2 ccc 需要得到结果: id values ------ ----------- 1 aa,bb 2 aaa,bbb,ccc 即, group by id, 求 value 的和(字符串相加)1. 旧的解决方法-- 1. 创建处理函数 CREATE FUNCTION dbo.f_str(@id int) RETURNS varchar(8000) AS BEGIN DECLARE @r varchar(8000) SET @r = '' SELECT @r = @r + ',' + value FROM tb WHERE id=@id RETURN STUFF(@r, 1, 1, '') END GO -- 调用函数SELECt id, values=dbo.f_str(id) FROM tb GROUP BY id-- 2. 新的解决方法 -- 示例数据 DECLARE @t TABLE(id int, value varchar(10)) INSERT @t SELECT 1, 'aa' UNION ALL SELECT 1, 'bb' UNION ALL SELECT 2, 'aaa' UNION ALL SELECT 2, 'bbb' UNION ALL SELECT 2, 'ccc'-- 查询处理 SELECT * FROM( SELECT DISTINCT id FROM @t )A OUTER APPLY( SELECT [values]= STUFF(REPLACE(REPLACE( ( SELECT value FROM @t N WHERE id = A.id FOR XML AUTO ), '<N value="', ','), '"/>', ''), 1, 1, '') )N/*--结果 id values ----------- ---------------- 1 aa,bb 2 aaa,bbb,ccc (2 行受影响) --*/--各种字符串分函数--3.3.1 使用游标法进行字符串合并处理的示例。 --处理的数据 CREATE TABLE tb(col1 varchar(10),col2 int) INSERT tb SELECT 'a',1 UNION ALL SELECT 'a',2 UNION ALL SELECT 'b',1 UNION ALL SELECT 'b',2 UNION ALL SELECT 'b',3--合并处理 --定义结果集表变量 DECLARE @t TABLE(col1 varchar(10),col2 varchar(100))--定义游标并进行合并处理 DECLARE tb CURSOR LOCAL FOR SELECT col1,col2 FROM tb ORDER BY col1,col2 DECLARE @col1_old varchar(10),@col1 varchar(10),@col2 int,@s varchar(100) OPEN tb FETCH tb INTO @col1,@col2 SELECT @col1_old=@col1,@s='' WHILE @@FETCH_STATUS=0 BEGIN IF @col1=@col1_old SELECT @s=@s+','+CAST(@col2 as varchar) ELSE BEGIN INSERT @t VALUES(@col1_old,STUFF(@s,1,1,'')) SELECT @s=','+CAST(@col2 as varchar),@col1_old=@col1 END FETCH tb INTO @col1,@col2 END INSERT @t VALUES(@col1_old,STUFF(@s,1,1,'')) CLOSE tb DEALLOCATE tb --显示结果并删除测试数据 SELECT * FROM @t DROP TABLE tb /*--结果 col1 col2 ---------- ----------- a 1,2 b 1,2,3 --*/ GO /*==============================================*/ --3.3.2 使用用户定义函数,配合SELECT处理完成字符串合并处理的示例 --处理的数据 CREATE TABLE tb(col1 varchar(10),col2 int) INSERT tb SELECT 'a',1 UNION ALL SELECT 'a',2 UNION ALL SELECT 'b',1 UNION ALL SELECT 'b',2 UNION ALL SELECT 'b',3 GO--合并处理函数 CREATE FUNCTION dbo.f_str(@col1 varchar(10)) RETURNS varchar(100) AS BEGIN DECLARE @re varchar(100) SET @re='' SELECT @re=@re+','+CAST(col2 as varchar) FROM tb WHERE col1=@col1 RETURN(STUFF(@re,1,1,'')) END GO--调用函数 SELECT col1,col2=dbo.f_str(col1) FROM tb GROUP BY col1 --删除测试 DROP TABLE tb DROP FUNCTION f_str /*--结果 col1 col2 ---------- ----------- a 1,2 b 1,2,3 --*/ GO/*==============================================*/ --3.3.3 使用临时表实现字符串合并处理的示例 --处理的数据 CREATE TABLE tb(col1 varchar(10),col2 int) INSERT tb SELECT 'a',1 UNION ALL SELECT 'a',2 UNION ALL SELECT 'b',1 UNION ALL SELECT 'b',2 UNION ALL SELECT 'b',3--合并处理 SELECT col1,col2=CAST(col2 as varchar(100)) INTO #t FROM tb ORDER BY col1,col2 DECLARE @col1 varchar(10),@col2 varchar(100) UPDATE #t SET @col2=CASE WHEN @col1=col1 THEN @col2+','+col2 ELSE col2 END, @col1=col1, col2=@col2 SELECT * FROM #t /*--更新处理后的临时表 col1 col2 ---------- ------------- a 1 a 1,2 b 1 b 1,2 b 1,2,3 --*/ --得到最终结果 SELECT col1,col2=MAX(col2) FROM #t GROUP BY col1 /*--结果 col1 col2 ---------- ----------- a 1,2 b 1,2,3 --*/ --删除测试 DROP TABLE tb,#t GO /*==============================================*/--3.3.4.1 每组 <=2 条记录的合并 --处理的数据 CREATE TABLE tb(col1 varchar(10),col2 int) INSERT tb SELECT 'a',1 UNION ALL SELECT 'a',2 UNION ALL SELECT 'b',1 UNION ALL SELECT 'b',2 UNION ALL SELECT 'c',3--合并处理 SELECT col1, col2=CAST(MIN(col2) as varchar) +CASE WHEN COUNT(*)=1 THEN '' ELSE ','+CAST(MAX(col2) as varchar) END FROM tb GROUP BY col1 DROP TABLE tb /*--结果 col1 col2 ---------- ---------- a 1,2 b 1,2 c 3 --*/--3.3.4.2 每组 <=3 条记录的合并 --处理的数据 CREATE TABLE tb(col1 varchar(10),col2 int) INSERT tb SELECT 'a',1 UNION ALL SELECT 'a',2 UNION ALL SELECT 'b',1 UNION ALL SELECT 'b',2 UNION ALL SELECT 'b',3 UNION ALL SELECT 'c',3--合并处理 SELECT col1, col2=CAST(MIN(col2) as varchar) +CASE WHEN COUNT(*)=3 THEN ',' +CAST((SELECT col2 FROM tb WHERE col1=a.col1 AND col2 NOT IN(MAX(a.col2),MIN(a.col2))) as varchar) ELSE '' END +CASE WHEN COUNT(*)>=2 THEN ','+CAST(MAX(col2) as varchar) ELSE '' END FROM tb a GROUP BY col1 DROP TABLE tb /*--结果 col1 col2 ---------- ------------ a 1,2 b 1,2,3 c 3 --*/ GO
--> 生成测试数据: @T DECLARE @T TABLE (ID INT,name VARCHAR(2)) INSERT INTO @T SELECT 1,'A' UNION ALL SELECT 2,'B' UNION ALL SELECT 3,'AE' UNION ALL SELECT 4,'CD' UNION ALL SELECT 5,'BW' UNION ALL SELECT 6,'CT' UNION ALL SELECT 7,'EN' UNION ALL SELECT 8,'AY'--SQL查询如下:SELECT ROW_NUMBER() OVER(ORDER BY A.name) AS Rid, REPLACE(B.name,' ',',') AS name FROM ( SELECT LEFT(name,1) AS name FROM @t GROUP BY LEFT(name,1) ) AS A CROSS APPLY( SELECT name=( SELECT name AS [data()] FROM @T WHERE LEFT(name,1)=A.name FOR XML PATH('') ) ) AS B/* Rid name -------------------- ------------------------------ 1 A,AE,AY 2 B,BW 3 CD,CT 4 EN(4 行受影响)*/
--> (让你望见影子的墙)生成测试数据,时间:2008-12-15
if not object_id('tb') is null drop table tb Go Create table tb([ID] int,[name] nvarchar(2)) Insert tb select 1,N'A' union all select 2,N'B' union all select 3,N'AE' union all select 4,N'CD' union all select 5,N'BW' union all select 6,N'CT' union all select 7,N'EN' union all select 8,N'AY' Go Select * from tbgo if object_id('F_Str') is not null drop function F_Str go create function F_Str(@name nvarchar(100)) returns nvarchar(100) as begin declare @S nvarchar(100) select @S=isnull(@S+',','')+name from Tb where name like '%'+left(@name,1)+'%' return @S end goselect distinct dbo.f_str(name) from tbA,AE,AY AE,EN B,BW CD,CT
select min(id),? from table1 group by substring(name,1,1) order by id asc; ?是把分组后name属性值连接起来的函数,新手,我也不知道啊,就想赚个分。
set nocount on if object_id('tb')is not null drop table tb go create table tb(ID int, name varchar(10)) -------------------------- insert tb select 1, 'A' insert tb select 2, 'B' insert tb select 3, 'AE' insert tb select 4, 'CD' insert tb select 5, 'BW' insert tb select 6, 'CT' insert tb select 7, 'EN' insert tb select 8, 'AY' if object_id('dbo.f_str')is not null drop function dbo.f_str go CREATE FUNCTION dbo.f_str(@name varchar(10)) RETURNS varchar(8000) AS BEGIN DECLARE @r varchar(8000) SET @r = '' SELECT @r = @r + ',' + name FROM tb WHERE left(name,1)=@name RETURN STUFF(@r, 1, 1, '') END GO select cnt=(select count(*)+1 from (select distinct dbo.f_str(left(name,1))name from tb)a where a.name<b.name),* from(select distinct dbo.f_str(left(name,1))name from tb )b /*cnt name ----------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 1 A,AE,AY 2 B,BW 3 CD,CT 4 EN*/
稍微改下: go if object_id('F_Str') is not null drop function F_Str go create function F_Str(@name nvarchar(100)) returns nvarchar(100) as begin declare @S nvarchar(100) select @S=isnull(@S+',','')+name from Tb where name like left(@name,1)+'%' return @S end goselect distinct dbo.f_str(name) from tb A,AE,AY B,BW CD,CT EN
if object_id('[tb]') is not null drop table [tb] go create table [tb]([ID] int,[name] varchar(2)) insert [tb] select 1,'A' union all select 2,'B' union all select 3,'AE' union all select 4,'CD' union all select 5,'BW' union all select 6,'CT' union all select 7,'EN' union all select 8,'AY'--select * from [tb]select id=row_number() over(order by left(name,1)) ,name=stuff((select ','+name from tb where left(name,1)=left(a.name,1) order by name for xml path('')),1,1,'') from tb a group by left(name,1) --测试结果: /* id name -------------------- ----------- 1 A,AE,AY 2 B,BW 3 CD,CT 4 EN(4 行受影响) */
/* 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
create TABLE tb(ID INT,name VARCHAR(2)) INSERT INTO tb SELECT 1,'A' UNION ALL SELECT 2,'B' UNION ALL SELECT 3,'AE' UNION ALL SELECT 4,'CD' UNION ALL SELECT 5,'BW' UNION ALL SELECT 6,'CT' UNION ALL SELECT 7,'EN' UNION ALL SELECT 8,'AY' gocreate function dbo.f_str(@name varchar(10)) returns varchar(100) as begin declare @str varchar(1000) set @str = '' select @str = @str + ',' + cast(name as varchar) from (select left(name,1) name1 , name from tb) t where left(name,1) = @name set @str = right(@str , len(@str) - 1) return @str end go--调用函数 select name1 , name = dbo.f_str(name1) from (select left(name,1) name1 , name from tb) t group by name1drop function dbo.f_str drop table tb /* name1 name ----- ------------------ A A,AE,AY B B,BW C CD,CT E EN */ (所影响的行数为 4 行)
无论是在sql 2000,还是在 sql 2005 中,都没有提供字符串的聚合函数,
所以,当我们在处理下列要求时,会比较麻烦:
有表tb, 如下:
id value
----- ------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
需要得到结果:
id values
------ -----------
1 aa,bb
2 aaa,bbb,ccc
即, group by id, 求 value 的和(字符串相加)1. 旧的解决方法-- 1. 创建处理函数
CREATE FUNCTION dbo.f_str(@id int)
RETURNS varchar(8000)
AS
BEGIN
DECLARE @r varchar(8000)
SET @r = ''
SELECT @r = @r + ',' + value
FROM tb
WHERE id=@id
RETURN STUFF(@r, 1, 1, '')
END
GO
-- 调用函数SELECt id, values=dbo.f_str(id)
FROM tb
GROUP BY id-- 2. 新的解决方法
-- 示例数据
DECLARE @t TABLE(id int, value varchar(10))
INSERT @t SELECT 1, 'aa'
UNION ALL SELECT 1, 'bb'
UNION ALL SELECT 2, 'aaa'
UNION ALL SELECT 2, 'bbb'
UNION ALL SELECT 2, 'ccc'-- 查询处理
SELECT *
FROM(
SELECT DISTINCT
id
FROM @t
)A
OUTER APPLY(
SELECT
[values]= STUFF(REPLACE(REPLACE(
(
SELECT value FROM @t N
WHERE id = A.id
FOR XML AUTO
), '<N value="', ','), '"/>', ''), 1, 1, '')
)N/*--结果
id values
----------- ----------------
1 aa,bb
2 aaa,bbb,ccc
(2 行受影响)
--*/--各种字符串分函数--3.3.1 使用游标法进行字符串合并处理的示例。
--处理的数据
CREATE TABLE tb(col1 varchar(10),col2 int)
INSERT tb SELECT 'a',1
UNION ALL SELECT 'a',2
UNION ALL SELECT 'b',1
UNION ALL SELECT 'b',2
UNION ALL SELECT 'b',3--合并处理
--定义结果集表变量
DECLARE @t TABLE(col1 varchar(10),col2 varchar(100))--定义游标并进行合并处理
DECLARE tb CURSOR LOCAL
FOR
SELECT col1,col2 FROM tb ORDER BY col1,col2
DECLARE @col1_old varchar(10),@col1 varchar(10),@col2 int,@s varchar(100)
OPEN tb
FETCH tb INTO @col1,@col2
SELECT @col1_old=@col1,@s=''
WHILE @@FETCH_STATUS=0
BEGIN
IF @col1=@col1_old
SELECT @s=@s+','+CAST(@col2 as varchar)
ELSE
BEGIN
INSERT @t VALUES(@col1_old,STUFF(@s,1,1,''))
SELECT @s=','+CAST(@col2 as varchar),@col1_old=@col1
END
FETCH tb INTO @col1,@col2
END
INSERT @t VALUES(@col1_old,STUFF(@s,1,1,''))
CLOSE tb
DEALLOCATE tb
--显示结果并删除测试数据
SELECT * FROM @t
DROP TABLE tb
/*--结果
col1 col2
---------- -----------
a 1,2
b 1,2,3
--*/
GO
/*==============================================*/
--3.3.2 使用用户定义函数,配合SELECT处理完成字符串合并处理的示例
--处理的数据
CREATE TABLE tb(col1 varchar(10),col2 int)
INSERT tb SELECT 'a',1
UNION ALL SELECT 'a',2
UNION ALL SELECT 'b',1
UNION ALL SELECT 'b',2
UNION ALL SELECT 'b',3
GO--合并处理函数
CREATE FUNCTION dbo.f_str(@col1 varchar(10))
RETURNS varchar(100)
AS
BEGIN
DECLARE @re varchar(100)
SET @re=''
SELECT @re=@re+','+CAST(col2 as varchar)
FROM tb
WHERE col1=@col1
RETURN(STUFF(@re,1,1,''))
END
GO--调用函数
SELECT col1,col2=dbo.f_str(col1) FROM tb GROUP BY col1
--删除测试
DROP TABLE tb
DROP FUNCTION f_str
/*--结果
col1 col2
---------- -----------
a 1,2
b 1,2,3
--*/
GO/*==============================================*/
--3.3.3 使用临时表实现字符串合并处理的示例
--处理的数据
CREATE TABLE tb(col1 varchar(10),col2 int)
INSERT tb SELECT 'a',1
UNION ALL SELECT 'a',2
UNION ALL SELECT 'b',1
UNION ALL SELECT 'b',2
UNION ALL SELECT 'b',3--合并处理
SELECT col1,col2=CAST(col2 as varchar(100))
INTO #t FROM tb
ORDER BY col1,col2
DECLARE @col1 varchar(10),@col2 varchar(100)
UPDATE #t SET
@col2=CASE WHEN @col1=col1 THEN @col2+','+col2 ELSE col2 END,
@col1=col1,
col2=@col2
SELECT * FROM #t
/*--更新处理后的临时表
col1 col2
---------- -------------
a 1
a 1,2
b 1
b 1,2
b 1,2,3
--*/
--得到最终结果
SELECT col1,col2=MAX(col2) FROM #t GROUP BY col1
/*--结果
col1 col2
---------- -----------
a 1,2
b 1,2,3
--*/
--删除测试
DROP TABLE tb,#t
GO
/*==============================================*/--3.3.4.1 每组 <=2 条记录的合并
--处理的数据
CREATE TABLE tb(col1 varchar(10),col2 int)
INSERT tb SELECT 'a',1
UNION ALL SELECT 'a',2
UNION ALL SELECT 'b',1
UNION ALL SELECT 'b',2
UNION ALL SELECT 'c',3--合并处理
SELECT col1,
col2=CAST(MIN(col2) as varchar)
+CASE
WHEN COUNT(*)=1 THEN ''
ELSE ','+CAST(MAX(col2) as varchar)
END
FROM tb
GROUP BY col1
DROP TABLE tb
/*--结果
col1 col2
---------- ----------
a 1,2
b 1,2
c 3
--*/--3.3.4.2 每组 <=3 条记录的合并
--处理的数据
CREATE TABLE tb(col1 varchar(10),col2 int)
INSERT tb SELECT 'a',1
UNION ALL SELECT 'a',2
UNION ALL SELECT 'b',1
UNION ALL SELECT 'b',2
UNION ALL SELECT 'b',3
UNION ALL SELECT 'c',3--合并处理
SELECT col1,
col2=CAST(MIN(col2) as varchar)
+CASE
WHEN COUNT(*)=3 THEN ','
+CAST((SELECT col2 FROM tb WHERE col1=a.col1 AND col2 NOT IN(MAX(a.col2),MIN(a.col2))) as varchar)
ELSE ''
END
+CASE
WHEN COUNT(*)>=2 THEN ','+CAST(MAX(col2) as varchar)
ELSE ''
END
FROM tb a
GROUP BY col1
DROP TABLE tb
/*--结果
col1 col2
---------- ------------
a 1,2
b 1,2,3
c 3
--*/
GO
-- Author: liangCK 小梁
-- Date : 2008-11-17 19:43:45
---------------------------------
--> 生成测试数据: @T
DECLARE @T TABLE (ID INT,name VARCHAR(2))
INSERT INTO @T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'AE' UNION ALL
SELECT 4,'CD' UNION ALL
SELECT 5,'BW' UNION ALL
SELECT 6,'CT' UNION ALL
SELECT 7,'EN' UNION ALL
SELECT 8,'AY'--SQL查询如下:SELECT
ROW_NUMBER() OVER(ORDER BY A.name) AS Rid,
REPLACE(B.name,' ',',') AS name
FROM (
SELECT LEFT(name,1) AS name
FROM @t
GROUP BY LEFT(name,1)
) AS A
CROSS APPLY(
SELECT name=(
SELECT name AS [data()]
FROM @T
WHERE LEFT(name,1)=A.name
FOR XML PATH('')
)
) AS B/*
Rid name
-------------------- ------------------------------
1 A,AE,AY
2 B,BW
3 CD,CT
4 EN(4 行受影响)*/
--> (让你望见影子的墙)生成测试数据,时间:2008-12-15
if not object_id('tb') is null
drop table tb
Go
Create table tb([ID] int,[name] nvarchar(2))
Insert tb
select 1,N'A' union all
select 2,N'B' union all
select 3,N'AE' union all
select 4,N'CD' union all
select 5,N'BW' union all
select 6,N'CT' union all
select 7,N'EN' union all
select 8,N'AY'
Go
Select * from tbgo
if object_id('F_Str') is not null
drop function F_Str
go
create function F_Str(@name nvarchar(100))
returns nvarchar(100)
as
begin
declare @S nvarchar(100)
select @S=isnull(@S+',','')+name from Tb where name like '%'+left(@name,1)+'%'
return @S
end
goselect distinct dbo.f_str(name) from tbA,AE,AY
AE,EN
B,BW
CD,CT
from table1
group by substring(name,1,1)
order by id asc;
?是把分组后name属性值连接起来的函数,新手,我也不知道啊,就想赚个分。
if object_id('tb')is not null drop table tb
go
create table tb(ID int, name varchar(10))
--------------------------
insert tb select 1, 'A'
insert tb select 2, 'B'
insert tb select 3, 'AE'
insert tb select 4, 'CD'
insert tb select 5, 'BW'
insert tb select 6, 'CT'
insert tb select 7, 'EN'
insert tb select 8, 'AY'
if object_id('dbo.f_str')is not null drop function dbo.f_str
go
CREATE FUNCTION dbo.f_str(@name varchar(10))
RETURNS varchar(8000)
AS
BEGIN
DECLARE @r varchar(8000)
SET @r = ''
SELECT @r = @r + ',' + name
FROM tb
WHERE left(name,1)=@name
RETURN STUFF(@r, 1, 1, '')
END
GO
select cnt=(select count(*)+1 from (select distinct dbo.f_str(left(name,1))name from tb)a where a.name<b.name),*
from(select distinct dbo.f_str(left(name,1))name from tb )b
/*cnt name
----------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1 A,AE,AY
2 B,BW
3 CD,CT
4 EN*/
go
if object_id('F_Str') is not null
drop function F_Str
go
create function F_Str(@name nvarchar(100))
returns nvarchar(100)
as
begin
declare @S nvarchar(100)
select @S=isnull(@S+',','')+name from Tb where name like left(@name,1)+'%'
return @S
end
goselect distinct dbo.f_str(name) from tb
A,AE,AY
B,BW
CD,CT
EN
go
create table [tb]([ID] int,[name] varchar(2))
insert [tb]
select 1,'A' union all
select 2,'B' union all
select 3,'AE' union all
select 4,'CD' union all
select 5,'BW' union all
select 6,'CT' union all
select 7,'EN' union all
select 8,'AY'--select * from [tb]select id=row_number() over(order by left(name,1))
,name=stuff((select ','+name from tb where left(name,1)=left(a.name,1) order by name for xml path('')),1,1,'')
from tb a
group by left(name,1)
--测试结果:
/*
id name
-------------------- -----------
1 A,AE,AY
2 B,BW
3 CD,CT
4 EN(4 行受影响)
*/
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
create TABLE tb(ID INT,name VARCHAR(2))
INSERT INTO tb
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'AE' UNION ALL
SELECT 4,'CD' UNION ALL
SELECT 5,'BW' UNION ALL
SELECT 6,'CT' UNION ALL
SELECT 7,'EN' UNION ALL
SELECT 8,'AY'
gocreate function dbo.f_str(@name varchar(10)) returns varchar(100)
as
begin
declare @str varchar(1000)
set @str = ''
select @str = @str + ',' + cast(name as varchar) from (select left(name,1) name1 , name from tb) t where left(name,1) = @name
set @str = right(@str , len(@str) - 1)
return @str
end
go--调用函数
select name1 , name = dbo.f_str(name1) from (select left(name,1) name1 , name from tb) t group by name1drop function dbo.f_str
drop table tb
/*
name1 name
----- ------------------
A A,AE,AY
B B,BW
C CD,CT
E EN
*/
(所影响的行数为 4 行)