select a,b,stuff((select ' '+c from [table] where a=t.a and b=t.b for xml path('')),1,1,'') from [table] t group by a,b
练练指法 --> 测试数据:# if object_id('tempdb.dbo.#') is not null drop table # create table #(a varchar(8), b varchar(8)) insert into # select '韩海民', 'QS0013' union all select '韩海民', 'QS0014' union all select '韩海民', 'QS0015' union all select '杨田', 'QS0013' union all select '杨田', 'QS0014'select a, ltrim((select ' '+b from # where a=t.a for xml path(''))) from # t group by a/* a -------- -------------------- 韩海民 QS0013 QS0014 QS0015 杨田 QS0013 QS0014 */
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 if not object_id('A') is null drop table A Go Create table A([id] int,[cname] nvarchar(2)) Insert A select 1,N'张三' union all select 2,N'李四' union all select 3,N'王五' union all select 4,N'蔡六' Go --> -->
if not object_id('B') is null drop table B Go Create table B([id] int,[cname] nvarchar(5)) Insert B select 1,N'1,2,3' union all select 2,N'3,4' Go create function F_str(@cname nvarchar(100)) returns nvarchar(100) as begin select @cname=replace(@cname,ID,[cname]) from A where patindex('%,'+rtrim(ID)+',%',','+@cname+',')>0 return @cname end go
--- -!!少了个字段--> 测试数据:# if object_id('tempdb.dbo.#') is not null drop table # create table #(a varchar(8), b varchar(8)) insert into # select '韩海民', 'QS0013' union all select '韩海民', 'QS0014' union all select '韩海民', 'QS0015' union all select '杨田', 'QS0013' union all select '杨田', 'QS0014'select a, stuff((select ' '+c from [table] where a=t.a and b=t.b for xml path('')),1,1,'') from # t group by a/* a -------- -------------------- 韩海民 QS0013 QS0014 QS0015 杨田 QS0013 QS0014 */
现在行列转换越来越多。怎么不搜一下呢。 csdn多的是
--> 测试数据:# if object_id('tempdb.dbo.#') is not null drop table # create table #(a varchar(8), b varchar(8)) insert into # select '韩海民', 'QS0013' union all select '韩海民', 'QS0014' union all select '韩海民', 'QS0015' union all select '杨田', 'QS0013' union all select '杨田', 'QS0014'select a, stuff((select '字段'+b from # where a=t.a for xml path('')),1,2,'')) from # t group by a/* a -------- -------------------- 韩海民 QS0013字段QS0014字段QS0015 杨田 QS0013字段QS0014 */
--> 测试数据:# if object_id('tempdb.dbo.#') is not null drop table # create table #(a varchar(8), b varchar(8)) insert into # select '韩海民', 'QS0013' union all select '韩海民', 'QS0014' union all select '韩海民', 'QS0015' union all select '杨田', 'QS0013' union all select '杨田', 'QS0014'select a, stuff((select '字段'+b from # where a=t.a for xml path('')),1,2,'')) from # t group by a/* a -------- -------------------- 韩海民 QS0013字段QS0014字段QS0015 杨田 QS0013字段QS0014 */
/*if object_id('temp') is not null drop table temp create table temp(a varchar(8), b varchar(8)) insert into temp select '韩海民', 'QS0013' union all select '韩海民', 'QS0014' union all select '韩海民', 'QS0015' union all select '杨田', 'QS0013' union all select '杨田', 'QS0014'*/--其实是要动态的,等等给你 with t as (select id=row_number() over (partition by a order by b),* from temp) select a,[1],[2],[3] from t pivot ( max(b) for id in([1],[2],[3]) ) as a /* 韩海民 QS0013 QS0014 QS0015 杨田 QS0013 QS0014 NULL */
declare @i varchar(5) set @i = (select top 1 count(b)as i from temp group by a order by count(b) desc) --明确最大列数,@i=3declare @s varchar(max) set @s='[1]'--第一列declare @j varchar(5) set @j=2 while @j<=@i begin set @s=@s+',['+@j+']' set @j=@j+1 end--循环,@s=[1],[2],[3]declare @str varchar(max)set @str='with t as(select id=row_number() over (partition by a order by b),* from temp) select a,'+@s+' from t pivot ( max(b) for id in('+@s+') ) as a 'exec(@str)/* 韩海民 QS0013 QS0014 QS0015 杨田 QS0013 QS0014 NULL */ 第一次写动态,请多多指教,应该有很多可以优化的地方。
select a,b,stuff((select ' '+c from [table] where a=t.a and b=t.b for xml path('')),1,1,'')
from [table] t group by a,b
--> 测试数据:#
if object_id('tempdb.dbo.#') is not null drop table #
create table #(a varchar(8), b varchar(8))
insert into #
select '韩海民', 'QS0013' union all
select '韩海民', 'QS0014' union all
select '韩海民', 'QS0015' union all
select '杨田', 'QS0013' union all
select '杨田', 'QS0014'select a, ltrim((select ' '+b from # where a=t.a for xml path(''))) from # t group by a/*
a
-------- --------------------
韩海民 QS0013 QS0014 QS0015
杨田 QS0013 QS0014
*/
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
if not object_id('A') is null
drop table A
Go
Create table A([id] int,[cname] nvarchar(2))
Insert A
select 1,N'张三' union all
select 2,N'李四' union all
select 3,N'王五' union all
select 4,N'蔡六'
Go
--> -->
if not object_id('B') is null
drop table B
Go
Create table B([id] int,[cname] nvarchar(5))
Insert B
select 1,N'1,2,3' union all
select 2,N'3,4'
Go
create function F_str(@cname nvarchar(100))
returns nvarchar(100)
as
begin
select @cname=replace(@cname,ID,[cname]) from A where patindex('%,'+rtrim(ID)+',%',','+@cname+',')>0
return @cname
end
go
--- -!!少了个字段--> 测试数据:#
if object_id('tempdb.dbo.#') is not null drop table #
create table #(a varchar(8), b varchar(8))
insert into #
select '韩海民', 'QS0013' union all
select '韩海民', 'QS0014' union all
select '韩海民', 'QS0015' union all
select '杨田', 'QS0013' union all
select '杨田', 'QS0014'select a, stuff((select ' '+c from [table] where a=t.a and b=t.b for xml path('')),1,1,'')
from # t group by a/*
a
-------- --------------------
韩海民 QS0013 QS0014 QS0015
杨田 QS0013 QS0014
*/
--> 测试数据:#
if object_id('tempdb.dbo.#') is not null drop table #
create table #(a varchar(8), b varchar(8))
insert into #
select '韩海民', 'QS0013' union all
select '韩海民', 'QS0014' union all
select '韩海民', 'QS0015' union all
select '杨田', 'QS0013' union all
select '杨田', 'QS0014'select a, stuff((select '字段'+b from # where a=t.a for xml path('')),1,2,'')) from # t group by a/*
a
-------- --------------------
韩海民 QS0013字段QS0014字段QS0015
杨田 QS0013字段QS0014
*/
--> 测试数据:#
if object_id('tempdb.dbo.#') is not null drop table #
create table #(a varchar(8), b varchar(8))
insert into #
select '韩海民', 'QS0013' union all
select '韩海民', 'QS0014' union all
select '韩海民', 'QS0015' union all
select '杨田', 'QS0013' union all
select '杨田', 'QS0014'select a, stuff((select '字段'+b from # where a=t.a for xml path('')),1,2,'')) from # t group by a/*
a
-------- --------------------
韩海民 QS0013字段QS0014字段QS0015
杨田 QS0013字段QS0014
*/
你们觉得lz会要这种作为最终结果?
韩海民 QS0013字段QS0014字段QS0015
杨田 QS0013字段QS0014
应该是指生成新的列吧...
create table temp(a varchar(8), b varchar(8))
insert into temp
select '韩海民', 'QS0013' union all
select '韩海民', 'QS0014' union all
select '韩海民', 'QS0015' union all
select '杨田', 'QS0013' union all
select '杨田', 'QS0014'*/--其实是要动态的,等等给你
with t as
(select id=row_number() over (partition by a order by b),* from temp)
select a,[1],[2],[3]
from t
pivot
(
max(b) for id in([1],[2],[3])
) as a
/*
韩海民 QS0013 QS0014 QS0015
杨田 QS0013 QS0014 NULL
*/
set @i = (select top 1 count(b)as i from temp group by a order by count(b) desc)
--明确最大列数,@i=3declare @s varchar(max)
set @s='[1]'--第一列declare @j varchar(5)
set @j=2
while @j<=@i
begin
set @s=@s+',['+@j+']'
set @j=@j+1
end--循环,@s=[1],[2],[3]declare @str varchar(max)set @str='with t as(select id=row_number() over (partition by a order by b),* from temp)
select a,'+@s+'
from t
pivot
(
max(b) for id in('+@s+')
) as a 'exec(@str)/*
韩海民 QS0013 QS0014 QS0015
杨田 QS0013 QS0014 NULL
*/
第一次写动态,请多多指教,应该有很多可以优化的地方。