1. 行列轉(zhuǎn)換--普通

假設(shè)有張學(xué)生成績表(CJ)如下
Name???? Subject????? Result
張三???? 語文???????? 80
張三???? 數(shù)學(xué)???????? 90
張三???? 物理???????? 85
李四???? 語文???????? 85
李四???? 數(shù)學(xué)???????? 92
李四???? 物理???????? 82

想變成????
姓名??? 語文??? 數(shù)學(xué)??? 物理
張三??? 80????? 90????? 85
李四??? 85????? 92????? 82

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 CJ) as a
select @sql = @sql+' from test group by name'
exec(@sql)

2. 行列轉(zhuǎn)換--合并

有表A,
id pid
1??? 1
1??? 2
1??? 3
2??? 1
2??? 2
3??? 1
如何化成表B:
id pid
?? 1?? 1,2,3
?? 2?? 1,2
?? 3?? 1

創(chuàng)建一個合并的函數(shù)
create function fmerg(@id int)
returns varchar(8000)
as
begin
declare @str varchar(8000)
set @str=''
select @str=@str+','+cast(pid as varchar) from 表A where id=@id set @str=right(@str,len(@str)-1)
return(@str)
End
go

--調(diào)用自定義函數(shù)得到結(jié)果
select distinct id,dbo.fmerg(id) from 表A

3. 如何取得一個數(shù)據(jù)表的所有列名

方法如下：先從SYSTEMOBJECT系統(tǒng)表中取得數(shù)據(jù)表的SYSTEMID,然后再SYSCOLUMN表中取得該數(shù)據(jù)表的所有列名。
SQL語句如下：
declare @objid int,@objname char(40)
set @objname = 'tablename'
select @objid = id from sysobjects where id = object_id(@objname)
select 'Column_name' = name from syscolumns where id = @objid order by colid

是不是太簡單了？ 呵呵 不過經(jīng)常用阿.

4. 通過SQL語句來更改用戶的密碼

修改別人的,需要sysadmin?? role????
EXEC?? sp_password?? NULL,?? 'newpassword',?? 'User'

如果帳號為SA執(zhí)行EXEC?? sp_password?? NULL,?? 'newpassword',?? sa??

5. 怎么判斷出一個表的哪些字段不允許為空？

select?? COLUMN_NAME?? from?? INFORMATION_SCHEMA.COLUMNS?? where?? IS_NULLABLE='NO'?? and?? TABLE_NAME=tablename??

6. 如何在數(shù)據(jù)庫里找到含有相同字段的表？
a. 查已知列名的情況
SELECT?? b.name?? as?? TableName,a.name?? as?? columnname??
From?? syscolumns???? a?? INNER?? JOIN???? sysobjects?? b????
ON?? a.id=b.id????
AND?? b.type='U'????
AND?? a.name='你的字段名字'??

b. 未知列名查所有在不同表出現(xiàn)過的列名
Select?? o.name?? As?? tablename,s1.name?? As?? columnname??
From?? syscolumns?? s1,?? sysobjects?? o??
Where?? s1.id?? =?? o.id??
??? And?? o.type?? =?? 'U'??
??? And?? Exists?? (??
??????? Select?? 1?? From?? syscolumns?? s2????
??????? Where?? s1.name?? =?? s2.name????
??????? And?? s1.id?? <>?? s2.id??
??????? )

7. 查詢第xxx行數(shù)據(jù)

假設(shè)id是主鍵：??
select?? *??
from?? (select?? top?? xxx?? *?? from?? yourtable)?? aa??
where?? not?? exists(select?? 1?? from?? (select?? top?? xxx-1?? *?? from?? yourtable)?? bb?? where?? aa.id=bb.id)
??
如果使用游標也是可以的??
fetch?? absolute?? [number]?? from?? [cursor_name]??
行數(shù)為絕對行數(shù)

8. SQL Server日期計算
a. 一個月的第一天
SELECT?? DATEADD(mm,?? DATEDIFF(mm,0,getdate()),?? 0)??
b. 本周的星期一
SELECT?? DATEADD(wk,?? DATEDIFF(wk,0,getdate()),?? 0)
c. 一年的第一天
SELECT?? DATEADD(yy,?? DATEDIFF(yy,0,getdate()),?? 0)??
d. 季度的第一天
SELECT?? DATEADD(qq,?? DATEDIFF(qq,0,getdate()),?? 0)??
e. 上個月的最后一天
SELECT?? dateadd(ms,-3,DATEADD(mm,?? DATEDIFF(mm,0,getdate()),?? 0))??
f. 去年的最后一天
SELECT?? dateadd(ms,-3,DATEADD(yy,?? DATEDIFF(yy,0,getdate()),?? 0))
g. 本月的最后一天
SELECT?? dateadd(ms,-3,DATEADD(mm,?? DATEDIFF(m,0,getdate())+1,?? 0))??
h. 本月的第一個星期一
select?? DATEADD(wk,?? DATEDIFF(wk,0,??????????????????????????????????????????????????????????
??????????????????????????????? dateadd(dd,6-datepart(day,getdate()),getdate())????????
????????????????????????????????????????????????????????????????????????????????????????????????? ),?? 0)??????
i. 本年的最后一天
SELECT?? dateadd(ms,-3,DATEADD(yy,?? DATEDIFF(yy,0,getdate())+1,?? 0))。

? SQL SERVER 與EXCEL的數(shù)據(jù)轉(zhuǎn)換 1、在SQL SERVER里查詢Excel數(shù)據(jù): -- ====================================================== SELECT * FROM OpenDataSource( 'Microsoft.Jet.OLEDB.4.0', 'Data Source="c:\book1.xls";User ID=Admin;Password=;Extended properties=Excel 5.0')...[Sheet1$] 下面是個查詢的示例，它通過用于 Jet 的 OLE DB 提供程序查詢 Excel 電子表格。 SELECT * FROM OpenDataSource ( 'Microsoft.Jet.OLEDB.4.0', 'Data Source="c:\Finance\account.xls";User ID=Admin;Password=;Extended properties=Excel 5.0')...xactions ------------------------------------------------------------------------------------------------- 2、將Excel的數(shù)據(jù)導(dǎo)入SQL server : -- ====================================================== SELECT * into newtable FROM OpenDataSource( 'Microsoft.Jet.OLEDB.4.0', 'Data Source="c:\book1.xls";User ID=Admin;Password=;Extended properties=Excel 5.0')...[Sheet1$] 實例: SELECT * into newtable FROM OpenDataSource( 'Microsoft.Jet.OLEDB.4.0', 'Data Source="c:\Finance\account.xls";User ID=Admin;Password=;Extended properties=Excel 5.0')...xactions ------------------------------------------------------------------------------------------------- 3、將SQL SERVER中查詢到的數(shù)據(jù)導(dǎo)成一個Excel文件 -- ====================================================== T-SQL代碼： EXEC master..xp_cmdshell 'bcp 庫名.dbo.表名out c:\Temp.xls -c -q -S"servername" -U"sa" -P""' 參數(shù)：S 是SQL服務(wù)器名；U是用戶；P是密碼 說明：還可以導(dǎo)出文本文件等多種格式 實例:EXEC master..xp_cmdshell 'bcp saletesttmp.dbo.CusAccount out c:\temp1.xls -c -q -S"pmserver" -U"sa" -P"sa"' EXEC master..xp_cmdshell 'bcp "SELECT au_fname, au_lname FROM pubs..authors ORDER BY au_lname" queryout C:\ authors.xls -c -Sservername -Usa -Ppassword' 在VB6中應(yīng)用ADO導(dǎo)出EXCEL文件代碼： Dim cn As New ADODB.Connection cn.open "Driver={SQL Server};Server=WEBSVR;DataBase=WebMis;UID=sa;WD=123;" cn.execute "master..xp_cmdshell 'bcp "SELECT col1, col2 FROM 庫名.dbo.表名" queryout E:\DT.xls -c -Sservername -Usa -Ppassword'" ------------------------------------------------------------------------------------------------- 4、在SQL SERVER里往Excel插入數(shù)據(jù): -- ====================================================== insert into OpenDataSource( 'Microsoft.Jet.OLEDB.4.0', 'Data Source="c:\Temp.xls";User ID=Admin;Password=;Extended properties=Excel 5.0')...table1 (A1,A2,A3) values (1,2,3) T-SQL代碼： INSERT INTO OPENDATASOURCE('Microsoft.JET.OLEDB.4.0', 'Extended Properties=Excel 8.0;Data source=C:\training\inventur.xls')...[Filiale1$] (bestand, produkt) VALUES (20, 'Test')

轉(zhuǎn)載于:https://www.cnblogs.com/maxthon/archive/2009/10/30/1593014.html

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