declare @t table (k int identity, a char);insert into @t values ('S');insert into @t values ('S');insert into @t values ('B');insert into @t values (' ');insert into @t values ('R');insert into @t values ('o');insert into @t values ('c');insert into @t values ('k');insert into @t values ('s');insert into @t values ('!');with cte(a, k)
as
(
select cast(t.a as varchar(max)), t.k from @t t
where k = 1
union all
select c.a + cast(t.a as varchar(max)), t.k
from @t t
join cte c on t.k = c.k+1)
select top 1 a from cte order by k desc
xml
declare @t table (k int identity, a char); insert into @t values ('S');
insert into @t values ('S');
insert into @t values ('B');
insert into @t values (' ');
insert into @t values ('R');
insert into @t values ('o');
insert into @t values ('c');
insert into @t values ('k');
insert into @t values ('s');
insert into @t values ('!'); SELECT
CONVERT(VARCHAR(50), myData) AS MyString
FROM
(
SELECT a AS [text()]
FROM @t
ORDER BY k
FOR XML PATH(''), TYPE
) x (myData)
create table tb1(编码 char(4),姓名 varchar(20))
insert tb1 select '0001' , '小李'
insert tb1 select '0002' , '小陈'
insert tb1 select '0003' , '小张'create table tb2(编码 char(4),部门 varchar(20))
insert tb2 select '0001','信息部'
insert tb2 select '0001','操作部'
insert tb2 select '0002','办公室'
insert tb2 select '0003','仓库部'
insert tb2 select '0003','办公室'SELECT B.编码,c.姓名,b.部门 FROM
(SELECT * FROM (select distinct 编码 from tb2) a OUTER apply
(SELECT
stuff(CONVERT(VARCHAR(50), mydata),1,1,'') AS 部门
FROM
(
select '、'+部门 as [text()]from tb2 where 编码=a.编码 for xml path(''),type
) x (myData)
)N)B inner join tb1 c on b.编码=c.编码
as
(
select cast(t.a as varchar(max)), t.k from @t t
where k = 1
union all
select c.a + cast(t.a as varchar(max)), t.k
from @t t
join cte c on t.k = c.k+1)
select top 1 a from cte order by k desc
xml
declare @t table (k int identity, a char); insert into @t values ('S');
insert into @t values ('S');
insert into @t values ('B');
insert into @t values (' ');
insert into @t values ('R');
insert into @t values ('o');
insert into @t values ('c');
insert into @t values ('k');
insert into @t values ('s');
insert into @t values ('!'); SELECT
CONVERT(VARCHAR(50), myData) AS MyString
FROM
(
SELECT a AS [text()]
FROM @t
ORDER BY k
FOR XML PATH(''), TYPE
) x (myData)
create table tb1(编码 char(4),姓名 varchar(20))
insert tb1 select '0001' , '小李'
insert tb1 select '0002' , '小陈'
insert tb1 select '0003' , '小张'create table tb2(编码 char(4),部门 varchar(20))
insert tb2 select '0001','信息部'
insert tb2 select '0001','操作部'
insert tb2 select '0002','办公室'
insert tb2 select '0003','仓库部'
insert tb2 select '0003','办公室'SELECT B.编码,c.姓名,b.部门 FROM
(SELECT * FROM (select distinct 编码 from tb2) a OUTER apply
(SELECT
stuff(CONVERT(VARCHAR(50), mydata),1,1,'') AS 部门
FROM
(
select '、'+部门 as [text()]from tb2 where 编码=a.编码 for xml path(''),type
) x (myData)
)N)B inner join tb1 c on b.编码=c.编码
--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
--*/
GODECLARE @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
----------- ----------------
1 aa,bb
2 aaa,bbb,ccc