数据库中有表A:A1,A2(若干条数据)
1,A
2,B
3,C
4,D
5,E
6,F
......要求:满足某一条件(比如:A1=2 or A1=3 or A1=6),输出未这样:
(1)B;(2)C;(3)F。
即得到A1满足某条件的所有的A2值,然后,输出时得到的第一个A2的值写在最前,写成这样(1)B加上分号,第二个接着前面写成(2)C加上分号,......(注意写完后,最后是句号,前面用分号)我要求语句写成:
select ????? from A where 对A1的条件(比如:A1=2 or A1=3 or A1=6) 中间 问号部分 不会。请问有无办法?
1,A
2,B
3,C
4,D
5,E
6,F
......要求:满足某一条件(比如:A1=2 or A1=3 or A1=6),输出未这样:
(1)B;(2)C;(3)F。
即得到A1满足某条件的所有的A2值,然后,输出时得到的第一个A2的值写在最前,写成这样(1)B加上分号,第二个接着前面写成(2)C加上分号,......(注意写完后,最后是句号,前面用分号)我要求语句写成:
select ????? from A where 对A1的条件(比如:A1=2 or A1=3 or A1=6) 中间 问号部分 不会。请问有无办法?
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (col1 INT,col2 VARCHAR(1))
INSERT INTO #T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'C' UNION ALL
SELECT 4,'D' UNION ALL
SELECT 5,'E' UNION ALL
SELECT 6,'F'--SQL查询如下:SELECT '('+RTRIM((SELECT COUNT(*)+1
FROM #T
WHERE col1 IN(2,3,6)
AND col1<t.col1))+')'+col2
FROM #T AS t
WHERE col1 IN(2,3,6);/*
---------------
(1)B
(2)C
(3)F(3 行受影响)*/
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (col1 INT,col2 VARCHAR(1))
INSERT INTO #T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'C' UNION ALL
SELECT 4,'D' UNION ALL
SELECT 5,'E' UNION ALL
SELECT 6,'F'--SQL查询如下:SELECT '('+RTRIM(ROW_NUMBER() OVER(ORDER BY col1))+')'+col2 AS col
FROM #T AS t
WHERE col1 IN(2,3,6);/*
col
---------------------------
(1)B
(2)C
(3)F(3 行受影响)*/
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)
--*/CSDN 社区帖子地址 附: 合并与分拆的CLR, sql2005的示例中有:
在安装sql 2005的示例后,默认安装目录为
drive:\Program Files\Microsoft SQL Server\90\Samples\Engine\Programmability\CLR\StringUtilities中
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.T') IS NOT NULL DROP TABLE T
CREATE TABLE T (col1 INT,col2 VARCHAR(1))
INSERT INTO T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'C' UNION ALL
SELECT 4,'D' UNION ALL
SELECT 5,'E' UNION ALL
SELECT 6,'F'--SQL查询如下:GOCREATE FUNCTION dbo.f_str(@id VARCHAR(50))
RETURNS varchar(50)
AS
BEGIN
DECLARE @r varchar(8000),@i int;
SET @r = ''
SET @i=1
SELECT @r=@r + ';' + '('+RTRIM(@i)+')'+col2,
@i=@i+1
FROM T
WHERE CHARINDEX(','+RTRIM(col1)+',',','+@id+',')>0
RETURN STUFF(@r, 1, 1, '')+'.'
END
GOSELECT dbo.f_str('2,3,6') colDROP TABLE T
DROP FUNCTION dbo.f_str/*
col
--------------------------------------------------
(1)B;(2)C;(3)F.(1 行受影响)*/
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (col1 INT,col2 VARCHAR(1))
INSERT INTO #T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'C' UNION ALL
SELECT 4,'D' UNION ALL
SELECT 5,'E' UNION ALL
SELECT 6,'F'--SQL查询如下:SELECT '('+RTRIM((SELECT COUNT(*)+1
FROM #T
WHERE col1 IN(2,3,6)
AND col1<t.col1))+')'+col2
FROM #T AS t
WHERE col1 IN(2,3,6);/*
---------------
(1)B
(2)C
(3)F(3 行受影响)*/
--> 生成测试数据: #T
IF OBJECT_ID('tempdb.dbo.#T') IS NOT NULL DROP TABLE #T
CREATE TABLE #T (col1 INT,col2 VARCHAR(1))
INSERT INTO #T
SELECT 1,'A' UNION ALL
SELECT 2,'B' UNION ALL
SELECT 3,'C' UNION ALL
SELECT 4,'D' UNION ALL
SELECT 5,'E' UNION ALL
SELECT 6,'F'--SQL查询如下:SELECT '('+RTRIM((SELECT COUNT(*)+1
FROM #T
WHERE col1 IN(2,3,6)
AND col1<t.col1))+')'+col2
FROM #T AS t
WHERE col1 IN(2,3,6);/*
---------------
(1)B
(2)C
(3)F(3 行受影响)*/正解