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q就产生了分布式查询的需? 阅读全文
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原著Q邹?
改编Q爱新觉|?毓华(十八q风?守得冰山雪莲花开) 2007-12-16 q东深圳
有表tb, 如下:
id value
----------- -----------
1 aa,bb
2 aaa,bbb,ccc
Ʋ按id,分拆value? 分拆后结果如?
id value
----------- --------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
1. 旧的解决Ҏ(sql server 2000)
SELECT TOP 8000 id = IDENTITY(int, 1, 1) INTO # FROM syscolumns a, syscolumns b
SELECT A.id, SUBSTRING(A.[values], B.id, CHARINDEX(',', A.[values] + ',', B.id) - B.id)
FROM tb A, # B
WHERE SUBSTRING(',' + A.[values], B.id, 1) = ','
DROP TABLE #
2. 新的解决Ҏ(sql server 2005)
create table tb(id int,value varchar(30))
insert into tb values(1,'aa,bb')
insert into tb values(2,'aaa,bbb,ccc')
go
SELECT A.id, B.value
FROM(
SELECT id, [value] = CONVERT(xml,' <root> <v>' + REPLACE([value], ',', ' </v> <v>') + ' </v> </root>') FROM tb
)A
OUTER APPLY(
SELECT value = N.v.value('.', 'varchar(100)') FROM A.[value].nodes('/root/v') N(v)
)B
DROP TABLE tb
/*
id value
----------- ------------------------------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
(5 行受影响)
*/
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Ҏ一Q?br />
SELECT * INTO XLImport3 FROM OPENDATASOURCE('Microsoft.Jet.OLEDB.4.0','Data Source=E:\Temp.xls;Extended Properties=Excel 5.0')...[Temp$]
Ҏ二：
SELECT * INTO XLImport4 FROM OPENROWSET('Microsoft.Jet.OLEDB.4.0','Excel 5.0;Database=E:\Temp.xls', [Temp$])
Ҏ三：
SELECT * INTO XLImport5 FROM OPENROWSET('Microsoft.Jet.OLEDB.4.0','Excel 5.0;Database=E:\Temp.xls', 'SELECT * FROM [Temp$]')
--像這個表裡面J續da錄
INSERT INTO XLImport5
SELECT * FROM OPENROWSET('Microsoft.Jet.OLEDB.4.0','Excel 5.0;Database=E:\Temp.xls', 'SELECT * FROM [Temp$]')
SELECT * FROM XLImport5
DROP TABLE XLImport3
DROP TABLE XLImport4
DROP TABLE XLImport5
[Temp$]指的時候你的Excel表格裡面的Sheet名稱Q記得美元符合是後面加上ȝQ是必須要加的，如果你的Excel?.0的，只需要Excel 5.0卛_?br />
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-- l你一个测试方法，从northwind中的orders表取数据?br />
select * into n1 from orders
select * into n2 from orders
select * from n1
select * from n2
--d主键Q然后修改n1中若q字D늚若干?br />
alter table n1 add constraint pk_n1_id primary key (OrderID)
alter table n2 add constraint pk_n2_id primary key (OrderID)
select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1
/* 应该可以Q而且不同的记录的ID昄出来。下面的适用于双方记录一L情况Q?/
select * from n1 where orderid in (select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
-- 至于双方互不存在的记录是比较好处理的
--删除n1,n2中若q条记录
delete from n1 where orderID in ('10728','10730')
delete from n2 where orderID in ('11000','11001')
--*************************************************************
-- 双方都有该记录却不完全相?br />
select * from n1 where orderid in(select OrderID from (select * from n1 union select * from n2) a group by OrderID having count(*) > 1)
union
--n2中存在但在n1中不存的?0728,10730
select * from n1 where OrderID not in (select OrderID from n2)
union
--n1中存在但在n2中不存的?1000,11001
select * from n2 where OrderID not in (select OrderID from n1)
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Name Subject Result
张三 语文 80
张三 数学 90
张三 物理 85
李四 语文 85
李四 数学 92
李四 物理 82
i果Q?br /> 姓名 语文 数学 物理
张三 80 90 85
李四 85 92 82
DROP TABLE Test
create table Test(Name varchar(10),Subject Varchar(10),Result int)
insert Test
select '張三','語文',80 union all
select '張三','數學',90 union all
select '張三','物理',85 union all
select '李四','語文',85 union all
select '李四','數學',92 union all
select '李四','物理',82
go
SELECT * FROM Test
--用於多行的轉?br />
declare @sql varchar(4000)
set @sql = 'select Name'
select @sql = @sql + ',sum(case Subject when '''+Subject+''' then Result end) ['+Subject+']'
from (select distinct Subject from test) as a
select @sql = @sql+' from test group by name'
exec(@sql)
--如果行數這個看起來更加明瞭
select Name as 姓名,
sum(case Subject when '數學' then Result end) [數學],
sum(case Subject when '物理' then Result end) [物理],
sum(case Subject when '語文' then Result end) [語文]
from Test group by name
我以前面試的時候考試過這種似的題Q也是我們在R程開發過程中經帔R到的一E常見題Q我的分析希望對大家有幫助?/p>
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b. 本周的星期一
SELECT DATEADD(wk, DATEDIFF(wk,0,getdate()), 0)
c. 一q的W一?br /> SELECT DATEADD(yy, DATEDIFF(yy,0,getdate()), 0)
d. 季度的第一?br /> SELECT DATEADD(qq, DATEDIFF(qq,0,getdate()), 0)
e. 上个月的最后一?br /> SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(mm,0,getdate()), 0))
f. d的最后一?br /> SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()), 0))
g. 本月的最后一?br /> SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,getdate())+1, 0))
h. 本月的第一个星期一
select DATEADD(wk, DATEDIFF(wk,0, dateadd(dd,6-datepart(day,getdate()),getdate()) ), 0)
i. 本年的最后一?br /> SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))
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