sql大全（二）
时间：2010-09-05 来源：Sunny Peng
承接sql大全（一）
总纲：
13. 工作日处理函数（标准节假日）
14. 工作日处理函数(自定义节假日)
15. 计算工作时间的函数
16. 复杂年月处理
17. 交叉表
18. 任意两个时间之间的星期几的次数
19. 统计--交叉表+日期+优先
20. 各种字符串分拆处理函数
21. 各种字符串合并处理示例
13.工作日处理函数(标准节假日)
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_WorkDay]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_WorkDay]
GO
--计算两个日期相差的工作天数
CREATE FUNCTION f_WorkDay(
@dt_begin datetime, --计算的开始日期
@dt_end datetime --计算的结束日期
)RETURNS int
AS
BEGIN
DECLARE @workday int,@i int,@bz bit,@dt datetime
IF @dt_begin>@dt_end
SELECT @bz=1,@dt=@dt_begin,@dt_begin=@dt_end,@dt_end=@dt
ELSE
SET @bz=0
SELECT @i=DATEDIFF(Day,@dt_begin,@dt_end)+1,
@workday=@i/7*5,
@dt_begin=DATEADD(Day,@i/7*7,@dt_begin)
WHILE @dt_begin<=@dt_end
BEGIN
SELECT @workday=CASE
WHEN (@@DATEFIRST+DATEPART(Weekday,@dt_begin)-1)%7 BETWEEN 1 AND 5
THEN @workday+1 ELSE @workday END,
@dt_begin=@dt_begin+1
END
RETURN(CASE WHEN @bz=1 THEN -@workday ELSE @workday END)
END
GO
/*=================================================================*/
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_WorkDayADD]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_WorkDayADD]
GO
--在指定日期上,增加指定工作天数后的日期
CREATE FUNCTION f_WorkDayADD(
@date datetime, --基础日期
@workday int --要增加的工作日数
)RETURNS datetime
AS
BEGIN
DECLARE @bz int
--增加整周的天数
SELECT @bz=CASE WHEN @workday<0 THEN -1 ELSE 1 END
,@date=DATEADD(Week,@workday/5,@date)
,@workday=@workday%5
--增加不是整周的工作天数
WHILE @workday<>0
SELECT @date=DATEADD(Day,@bz,@date),
@workday=CASE WHEN (@@DATEFIRST+DATEPART(Weekday,@date)-1)%7 BETWEEN 1 AND 5
THEN @workday-@bz ELSE @workday END
--避免处理后的日期停留在非工作日上
WHILE (@@DATEFIRST+DATEPART(Weekday,@date)-1)%7 in(0,6)
SET @date=DATEADD(Day,@bz,@date)
RETURN(@date)
END
14.工作日处理函数(自定义节假日)
if exists (select * from dbo.sysobjects where id = object_id(N'[tb_Holiday]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [tb_Holiday]
GO
--定义节假日表
CREATE TABLE tb_Holiday(
HDate smalldatetime primary key clustered, --节假日期
Name nvarchar(50) not null) --假日名称
GO
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_WorkDay]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_WorkDay]
GO
--计算两个日期之间的工作天数
CREATE FUNCTION f_WorkDay(
@dt_begin datetime, --计算的开始日期
@dt_end datetime --计算的结束日期
)RETURNS int
AS
BEGIN
IF @dt_begin>@dt_end
RETURN(DATEDIFF(Day,@dt_begin,@dt_end)
+1-(
SELECT COUNT(*) FROM tb_Holiday
WHERE HDate BETWEEN @dt_begin AND @dt_end))
RETURN(-(DATEDIFF(Day,@dt_end,@dt_begin)
+1-(
SELECT COUNT(*) FROM tb_Holiday
WHERE HDate BETWEEN @dt_end AND @dt_begin)))
END
GO
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_WorkDayADD]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_WorkDayADD]
GO
--在指定日期上增加工作天数
CREATE FUNCTION f_WorkDayADD(
@date datetime, --基础日期
@workday int --要增加的工作日数
)RETURNS datetime
AS
BEGIN
IF @workday>0
WHILE @workday>0
SELECT @date=@date+@workday,@workday=count(*)
FROM tb_Holiday
WHERE HDate BETWEEN @date AND @date+@workday
ELSE
WHILE @workday<0
SELECT @date=@date+@workday,@workday=-count(*)
FROM tb_Holiday
WHERE HDate BETWEEN @date AND @date+@workday
RETURN(@date)
END
15.计算工作时间的函数
if exists (select * from dbo.sysobjects where id = object_id(N'[tb_worktime]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [tb_worktime]
GO
--定义工作时间表
CREATE TABLE tb_worktime(
ID int identity(1,1) PRIMARY KEY, --序号
time_start smalldatetime, --工作的开始时间
time_end smalldatetime, --工作的结束时间
worktime AS DATEDIFF(Minute,time_start,time_end) --工作时数(分钟)
)
GO
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_WorkTime]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_WorkTime]
GO
--计算两个日期之间的工作时间
CREATE FUNCTION f_WorkTime(
@date_begin datetime, --计算的开始时间
@date_end datetime --计算的结束时间
)RETURNS int
AS
BEGIN
DECLARE @worktime int
IF DATEDIFF(Day,@date_begin,@date_end)=0
SELECT @worktime=SUM(DATEDIFF(Minute,
CASE WHEN CONVERT(VARCHAR,@date_begin,108)>time_start
THEN CONVERT(VARCHAR,@date_begin,108)
ELSE time_start END,
CASE WHEN CONVERT(VARCHAR,@date_end,108)<time_end
THEN CONVERT(VARCHAR,@date_end,108)
ELSE time_end END))
FROM tb_worktime
WHERE time_end>CONVERT(VARCHAR,@date_begin,108)
AND time_start<CONVERT(VARCHAR,@date_end,108)
ELSE
SET @worktime
=(SELECT SUM(CASE
WHEN CONVERT(VARCHAR,@date_begin,108)>time_start
THEN DATEDIFF(Minute,CONVERT(VARCHAR,@date_begin,108),time_end)
ELSE worktime END)
FROM tb_worktime
WHERE time_end>CONVERT(VARCHAR,@date_begin,108))
+(SELECT SUM(CASE
WHEN CONVERT(VARCHAR,@date_end,108)<time_end
THEN DATEDIFF(Minute,time_start,CONVERT(VARCHAR,@date_end,108))
ELSE worktime END)
FROM tb_worktime
WHERE time_start<CONVERT(VARCHAR,@date_end,108))
+CASE
WHEN DATEDIFF(Day,@date_begin,@date_end)>1
THEN (DATEDIFF(Day,@date_begin,@date_end)-1)
*(SELECT SUM(worktime) FROM tb_worktime)
ELSE 0 END
RETURN(@worktime)
END
16.复杂年月处理
--定义基本数字表
declare @T1 table(代码 int,名称 varchar(10),参加时间 datetime,终止时间 datetime)
insert into @T1
select 12,'单位1','2003/04/01','2004/05/01'
union all select 22,'单位2','2001/02/01','2003/02/01'
union all select 42,'单位3','2000/04/01','2003/05/01'
union all select 25,'单位5','2003/04/01','2003/05/01'
--定义年表
declare @NB table(代码 int,名称 varchar(10),年份 int)
insert into @NB
select 12,'单位1',2003
union all select 12,'单位1',2004
union all select 22,'单位2',2001
union all select 22,'单位2',2002
union all select 22,'单位2',2003
--定义月表
declare @YB table(代码 int,名称 varchar(10),年份 int,月份 varchar(2))
insert into @YB
select 12,'单位1',2003,'04'
union all select 22,'单位2',2001,'01'
union all select 22,'单位2',2001,'12'
--为年表+月表数据处理准备临时表
select top 8246 y=identity(int,1753,1)
into #tby from
(select id from syscolumns) a,
(select id from syscolumns) b,
(select id from syscolumns) c
--为月表数据处理准备临时表
select top 12 m=identity(int,1,1)
into #tbm from syscolumns
/*--数据处理--*/
--年表数据处理
select a.*
from(
select a.代码,a.名称,年份=b.y
from @T1 a,#tby b
where b.y between year(参加时间) and year(终止时间)
) a left join @NB b on a.代码=b.代码 and a.年份=b.年份
where b.代码 is null
--月表数据处理
select a.*
from(
select a.代码,a.名称,年份=b.y,月份=right('00'+cast(c.m as varchar),2)
from @T1 a,#tby b,#tbm c
where b.y*100+c.m between convert(varchar(6),参加时间,112)
and convert(varchar(6),终止时间,112)
) a left join @YB b on a.代码=b.代码 and a.年份=b.年份 and a.月份=b.月份
where b.代码 is null
order by a.代码,a.名称,a.年份,a.月份
--删除数据处理临时表
drop table #tby,#tbm
17.交叉表
--示例
--示例数据
create table tb(ID int,Time datetime)
insert tb select 1,'2005/01/24 16:20'
union all select 2,'2005/01/23 22:45'
union all select 3,'2005/01/23 0:30'
union all select 4,'2005/01/21 4:28'
union all select 5,'2005/01/20 13:22'
union all select 6,'2005/01/19 20:30'
union all select 7,'2005/01/19 18:23'
union all select 8,'2005/01/18 9:14'
union all select 9,'2005/01/18 18:04'
go
--查询处理：
select case when grouping(b.Time)=1 then 'Total' else b.Time end,
[Mon]=sum(case a.week when 1 then 1 else 0 end),
[Tue]=sum(case a.week when 2 then 1 else 0 end),
[Wed]=sum(case a.week when 3 then 1 else 0 end),
[Thu]=sum(case a.week when 4 then 1 else 0 end),
[Fri]=sum(case a.week when 5 then 1 else 0 end),
[Sat]=sum(case a.week when 6 then 1 else 0 end),
[Sun]=sum(case a.week when 0 then 1 else 0 end),
[Total]=count(a.week)
from(
select Time=convert(char(5),dateadd(hour,-1,Time),108)
--时间交界点是1am,所以减1小时，避免进行跨天处理
,week=(@@datefirst+datepart(weekday,Time)-1)%7
--考虑@@datefirst对datepart的影响
from tb
)a right join(
select id=1,a='16:00',b='19:59',Time='[5pm - 9pm)' union all
select id=2,a='20:00',b='23:59',Time='[9pm - 1am)' union all
select id=3,a='00:00',b='02:59',Time='[1am - 4am)' union all
select id=4,a='03:00',b='07:29',Time='[4am - 8:30am)' union all
select id=5,a='07:30',b='11:59',Time='[8:30am - 1pm)' union all
select id=6,a='12:00',b='15:59',Time='[1pm - 5pm)'
)b on a.Time>=b.a and a.Time<b.b
group by b.id,b.Time with rollup
having grouping(b.Time)=0 or grouping(b.id)=1
go
--删除测试
drop table tb
/*--测试结果
Mon Tue Wed Thu Fri Sat Sun Total
-------------- ----- ----- ----- ----- ----- ------ ---- -------
[5pm - 9pm) 0 1 2 0 0 0 0 3
[9pm - 1am) 0 0 0 0 0 0 2 2
[1am - 4am) 0 0 0 0 0 0 0 0
[4am - 8:30am) 0 0 0 0 1 0 0 1
[8:30am - 1pm) 0 1 0 0 0 0 0 1
[1pm - 5pm) 1 0 0 1 0 0 0 2
Total 1 2 2 1 1 0 2 9
（所影响的行数为 7 行）
--*/
18.任意两个时间之间的星期几的次数
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_weekdaycount]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_weekdaycount]
GO
/*--计算任意两个时间之间的星期几的次数(横向显示)
本方法直接判断 @@datefirst 做对应处理
不受 sp_language 及 set datefirst 的影响
--邹建 2004.08(引用请保留此信息)--*/
/*--调用示例
select * from f_weekdaycount('2004-9-01','2004-9-02')
--*/
create function f_weekdaycount(
@dt_begin datetime,
@dt_end datetime
)returns table
as
return(
select 跨周数
,周一=case a
when -1 then case when 1 between b and c then 1 else 0 end
when 0 then case when b<=1 then 1 else 0 end
+case when c>=1 then 1 else 0 end
else a+case when b<=1 then 1 else 0 end
+case when c>=1 then 1 else 0 end
end
,周二=case a
when -1 then case when 2 between b and c then 1 else 0 end
when 0 then case when b<=2 then 1 else 0 end
+case when c>=2 then 1 else 0 end
else a+case when b<=2 then 1 else 0 end
+case when c>=2 then 1 else 0 end
end
,周三=case a
when -1 then case when 3 between b and c then 1 else 0 end
when 0 then case when b<=3 then 1 else 0 end
+case when c>=3 then 1 else 0 end
else a+case when b<=3 then 1 else 0 end
+case when c>=3 then 1 else 0 end
end
,周四=case a
when -1 then case when 4 between b and c then 1 else 0 end
when 0 then case when b<=4 then 1 else 0 end
+case when c>=4 then 1 else 0 end
else a+case when b<=4 then 1 else 0 end
+case when c>=4 then 1 else 0 end
end
,周五=case a
when -1 then case when 5 between b and c then 1 else 0 end
when 0 then case when b<=5 then 1 else 0 end
+case when c>=5 then 1 else 0 end
else a+case when b<=5 then 1 else 0 end
+case when c>=5 then 1 else 0 end
end
,周六=case a
when -1 then case when 6 between b and c then 1 else 0 end
when 0 then case when b<=6 then 1 else 0 end
+case when c>=6 then 1 else 0 end
else a+case when b<=6 then 1 else 0 end
+case when c>=6 then 1 else 0 end
end
,周日=case a
when -1 then case when 0 between b and c then 1 else 0 end
when 0 then case when b<=0 then 1 else 0 end
+case when c>=0 then 1 else 0 end
else a+case when b<=0 then 1 else 0 end
+case when c>=0 then 1 else 0 end
end
from(
select 跨周数=case when @dt_begin<@dt_end
then (datediff(day,@dt_begin,@dt_end)+7)/7
else (datediff(day,@dt_end,@dt_begin)+7)/7 end
,a=case when @dt_begin<@dt_end
then datediff(week,@dt_begin,@dt_end)-1
else datediff(week,@dt_end,@dt_begin)-1 end
,b=case when @dt_begin<@dt_end
then (@@datefirst+datepart(weekday,@dt_begin)-1)%7
else (@@datefirst+datepart(weekday,@dt_end)-1)%7 end
,c=case when @dt_begin<@dt_end
then (@@datefirst+datepart(weekday,@dt_end)-1)%7
else (@@datefirst+datepart(weekday,@dt_begin)-1)%7 end)a
)
go
19.统计--交叉表+日期+优先
--交叉表,根据优先级取数据,日期处理
create table tb(qid int,rid nvarchar(4),tagname nvarchar(10),starttime smalldatetime,endtime smalldatetime,startweekday int,endweekday int,startdate smalldatetime,enddate smalldatetime,d int)
insert tb select 1,'A1','未订','08:00','09:00',1 ,5 ,null ,null ,1
union all select 1,'A1','未订','09:00','10:00',1 ,5 ,null ,null ,1
union all select 1,'A1','未订','10:00','11:00',1 ,5 ,null ,null ,1
union all select 1,'A1','装修','08:00','09:00',null,null,'2005-1-18','2005-1-19',2
--union all select 1,'A1','装修','09:00','10:00',null,null,'2005-1-18','2005-1-19',2
union all select 1,'A1','装修','10:00','11:00',null,null,'2005-1-18','2005-1-19',2
union all select 1,'A2','未订','08:00','09:00',1 ,5 ,null ,null ,1
union all select 1,'A2','未订','09:00','10:00',1 ,5 ,null ,null ,1
union all select 1,'A2','未订','10:00','11:00',1 ,5 ,null ,null ,1
--union all select 1,'A2','装修','08:00','09:00',null,null,'2005-1-18','2005-1-19',2
union all select 1,'A2','装修','09:00','10:00',null,null,'2005-1-18','2005-1-19',2
--union all select 1,'A2','装修','10:00','11:00',null,null,'2005-1-18','2005-1-19',2
go
/*--楼主这个问题要考虑几个方面
1. 取星期时,set datefirst 的影响
2. 优先级问题
3. qid,rid 应该是未知的(动态变化的)
--*/
--实现的存储过程如下
create proc p_qry
@date smalldatetime --要查询的日期
as
set nocount on
declare @week int,@s nvarchar(4000)
--格式化日期和得到星期
select @date=convert(char(10),@date,120)
,@week=(@@datefirst+datepart(weekday,@date)-1)%7
,@s=' '
select id=identity(int),* into #t
from(
select top 100 percent
qid,rid,tagname,
starttime=convert(char(5),starttime,108),
endtime=convert(char(5),endtime,108)
from tb
where (@week between startweekday and endweekday)
or(@date between startdate and enddate)
order by qid,rid,starttime,d desc)a
select @s=@s+N',['+rtrim(rid)
+N']=max(case when qid='+rtrim(qid)
+N' and rid=N'''+rtrim(rid)
+N''' then tagname else N'''' end)'
from #t group by qid,rid
exec('
select starttime,endtime'+@s+'
from #t a
where not exists(
select * from #t
where qid=a.qid and rid=a.rid
and starttime=a.starttime
and endtime=a.endtime
and id<a.id)
group by starttime,endtime')
go
--调用
exec p_qry '2005-1-17'
exec p_qry '2005-1-18'
go
--删除测试
drop table tb
drop proc p_qry
/*--测试结果
starttime endtime A1 A2
--------- ------- ---------- ----------
08:00 09:00 未订 未订
09:00 10:00 未订 未订
10:00 11:00 未订 未订
starttime endtime A1 A2
--------- ------- ---------- ----------
08:00 09:00 装修 未订
09:00 10:00 未订 装修
10:00 11:00 装修 未订
--*/
20.各种字符串分拆处理函数
--各种字符串分函数
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3.2.1 循环截取法
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(col varchar(100))
AS
BEGIN
DECLARE @splitlen int
SET @splitlen=LEN(@split+'a')-2
WHILE CHARINDEX(@split,@s)>0
BEGIN
INSERT @re VALUES(LEFT(@s,CHARINDEX(@split,@s)-1))
SET @s=STUFF(@s,1,CHARINDEX(@split,@s)+@splitlen,' ')
END
INSERT @re VALUES(@s)
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3.2.3.1 使用临时性分拆辅助表法
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(col varchar(100))
AS
BEGIN
--创建分拆处理的辅助表(用户定义函数中只能操作表变量)
DECLARE @t TABLE(ID int IDENTITY,b bit)
INSERT @t(b) SELECT TOP 8000 0 FROM syscolumns a,syscolumns b
INSERT @re SELECT SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID)
FROM @t
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[tb_splitSTR]') and objectproperty(id,N'IsUserTable')=1)
drop table [dbo].[tb_splitSTR]
GO
--3.2.3.2 使用永久性分拆辅助表法
--字符串分拆辅助表
SELECT TOP 8000 ID=IDENTITY(int,1,1) INTO dbo.tb_splitSTR
FROM syscolumns a,syscolumns b
GO
--字符串分拆处理函数
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS TABLE
AS
RETURN(
SELECT col=CAST(SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID) as varchar(100))
FROM tb_splitSTR
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID)
GO
/*==============================================*/
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3.2.5 将数据项按数字与非数字再次拆份
CREATE FUNCTION f_splitSTR(
@s varchar(8000), --待分拆的字符串
@split varchar(10) --数据分隔符
)RETURNS @re TABLE(No varchar(100),Value varchar(20))
AS
BEGIN
--创建分拆处理的辅助表(用户定义函数中只能操作表变量)
DECLARE @t TABLE(ID int IDENTITY,b bit)
INSERT @t(b) SELECT TOP 8000 0 FROM syscolumns a,syscolumns b
INSERT @re
SELECT No=REVERSE(STUFF(col,1,PATINDEX('%[^-^.^0-9]%',col+'a')-1,' ')),
Value=REVERSE(LEFT(col,PATINDEX('%[^-^.^0-9]%',col+'a')-1))
FROM(
SELECT col=REVERSE(SUBSTRING(@s,ID,CHARINDEX(@split,@s+@split,ID)-ID))
FROM @t
WHERE ID<=LEN(@s+'a')
AND CHARINDEX(@split,@split+@s,ID)=ID)a
RETURN
END
GO
/*==============================================*/
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[f_splitSTR]') and xtype in (N'FN', N'IF', N'TF'))
drop function [dbo].[f_splitSTR]
GO
--3.2.6 分拆短信数据
CREATE FUNCTION f_splitSTR(@s varchar(8000))
RETURNS @re TABLE(split varchar(10),value varchar(100))
AS
BEGIN
DECLARE @splits TABLE(split varchar(10),splitlen as LEN(split))
INSERT @splits(split)
SELECT 'AC' UNION ALL
SELECT 'BC' UNION ALL
SELECT 'CC' UNION ALL
SELECT 'DC'
DECLARE @pos1 int,@pos2 int,@split varchar(10),@splitlen int
SELECT TOP 1
@pos1=1,@split=split,@splitlen=splitlen
FROM @splits
WHERE @s LIKE split+'%'
WHILE @pos1>0
BEGIN
SELECT TOP 1
@pos2=CHARINDEX(split,@s,@splitlen+1)
FROM @splits
WHERE CHARINDEX(split,@s,@splitlen+1)>0
ORDER BY CHARINDEX(split,@s,@splitlen+1)
IF @@ROWCOUNT=0
BEGIN
INSERT @re VALUES(@split,STUFF(@s,1,@splitlen,' '))
RETURN
END
ELSE
BEGIN
INSERT @re VALUES(@split,SUBSTRING(@s,@splitlen+1,@pos2-@splitlen-1))
SELECT TOP 1
@pos1=1,@split=split,@splitlen=splitlen,@s=STUFF(@s,1,@pos2-1,' ')
FROM @splits
WHERE STUFF(@s,1,@pos2-1,'') LIKE split+'%'
END
END
RETURN
END
GO
21.各种字符串合并处理示例
--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
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