SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 H;is/
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一、基础 e
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1、说明:创建数据库 PJ')R:e,
CREATE DATABASE database-name _1X!EH"
2、说明:删除数据库 a9e>iU
drop database dbname T}Tp$.gB
3、说明:备份sql server W<{h,j8
--- 创建 备份数据的 device !"AvY y9
USE master q~Hn-5H4Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' k:i4=5^*GX
--- 开始 备份 Mc
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BACKUP DATABASE pubs TO testBack Ha#=(9.
4、说明:创建新表 c?Y*Y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _`$qBw.Nx
根据已有的表创建新表: KRbvj
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only *][`@@->
5、说明:删除新表 y8y5*e~A-)
drop table tabname Yu/ID!`Z
6、说明:增加一个列 ^S<Y>Nm]
Alter table tabname add column col type Sz
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 wVXS%4|v
7、说明:添加主键: Alter table tabname add primary key(col) Z3e| UAif
说明:删除主键: Alter table tabname drop primary key(col) ,]C;sN%~}
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?5__oT
删除索引:drop index idxname k8yEdi`
注:索引是不可更改的,想更改必须删除重新建。 hR
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9、说明:创建视图:create view viewname as select statement 1.JK33
删除视图:drop view viewname KM0ru
10、说明:几个简单的基本的sql语句 *-WpZGh
选择:select * from table1 where 范围 hW')Sp
插入:insert into table1(field1,field2) values(value1,value2) _{O>v\u
删除:delete from table1 where 范围 ? V1*cVD6i
更新:update table1 set field1=value1 where 范围 ;a!S!%.h
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! T"Y+m-<%
排序:select * from table1 order by field1,field2 [desc] 234p9A@
总数:select count as totalcount from table1 @u+]aI!`-
求和:select sum(field1) as sumvalue from table1 OO\+J
平均:select avg(field1) as avgvalue from table1 ;}WeTA_-[
最大:select max(field1) as maxvalue from table1 ]EbM9Fo-U
最小:select min(field1) as minvalue from table1 eIF5ZPSZi
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11、说明:几个高级查询运算词 @IKYh{j4
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A: UNION 运算符 Q} JOU
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 +/7?HGf
B: EXCEPT 运算符 /N+dQe
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Gu,wF(x7A
C: INTERSECT 运算符 8nqG<!,q
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 N% B>M7-=
注:使用运算词的几个查询结果行必须是一致的。 ]m q|w
12、说明:使用外连接 ~_)^X
A、left outer join: .LZ?S"z$w
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 octL"t8w
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c s^TZXCyF o
B:right outer join: %0?KMRr
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ]q[D>6_
C:full outer join: 1\m[$Gs:
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 -ad{tJV|
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二、提升 klYX7?
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 4@gG<QJW
法一:select * into b from a where 1<>1 Hio0HL-
法二:select top 0 * into b from a E=Bf1/c\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) `[yKFa
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insert into b(a, b, c) select d,e,f from b; fbvL7*
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) VGN5<?PrN
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #%2rP'He
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 6_;icpN]
4、说明:子查询(表名1:a 表名2:b) Vp\,CuQ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) _61gF[r4!Y
5、说明:显示文章、提交人和最后回复时间 |-ALklXr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) {S\{Ii6
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Dy&i&5E.-l
7、说明:在线视图查询(表名1:a ) Gz0]}]A
select * from (SELECT a,b,c FROM a) T where t.a > 1; e`s
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 8Fh)eha9f
select * from table1 where time between time1 and time2 U/M>?G~
select a,b,c, from table1 where a not between 数值1 and 数值2 q?:dCFw$x5
9、说明:in 的使用方法 &-w
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select * from table1 where a [not] in ('值1','值2','值4','值6') tOD6&<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3}1u\(Mf
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pki%vRY
11、说明:四表联查问题: r5/0u(\LB
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... FV!q!D
12、说明:日程安排提前五分钟提醒 ^\% (,KNo
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8,%^
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13、说明:一条sql 语句搞定数据库分页 gJ{)-\
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Fo_sgv8O<
14、说明:前10条记录 ~?}Emn;t
select top 10 * form table1 where 范围 ~~P5k:
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) kTB0b*V
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) C )
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 0+ '&`Q!u
(select a from tableA ) except (select a from tableB) except (select a from tableC) 5tkAFb4P
17、说明:随机取出10条数据 $PPi5f}HD
select top 10 * from tablename order by newid() Zi
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18、说明:随机选择记录 Q&;9x? e
select newid() b|DdG/O
19、说明:删除重复记录 (t|Zn@uY
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w9imKVry
20、说明:列出数据库里所有的表名 *^4"5X@
select name from sysobjects where type='U' n>XdU%&
21、说明:列出表里的所有的 <lPG=Xt
select name from syscolumns where id=object_id('TableName') V!=,0zy~Z
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 q;CiV
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type A)!*]o>U
显示结果: x,-75
type vender pcs J@'wf8Ub
电脑 A 1 ITBE|b
电脑 A 1 p
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光盘 B 2 3$R1ipb
光盘 A 2 e !Y~Qy
手机 B 3 !pW0qX\1n
手机 C 3 T^KKy0ZGM
23、说明:初始化表table1 }0z)5c
TRUNCATE TABLE table1 GxxW&y
24、说明:选择从10到15的记录 %> eiAB_b
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7}>E J
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三、技巧 SnfYT)Ph
1、1=1,1=2的使用,在SQL语句组合时用的较多 \2$|Ei7
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \8cx6 G'
如: w@E3ZL^
if @strWhere !='' niyV8v
begin tWRC$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >GRxHK@G
end RrB&\9=
else
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begin >bW#Zs,6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' )t#W{Gzfmh
end TJRCH>E[a
我们可以直接写成 ^h6tr8yn
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere R 9\*#c
2、收缩数据库 3pKQ$\u
--重建索引 6_Y,eL]"
DBCC REINDEX D,feF9
DBCC INDEXDEFRAG ?tbrbkx
--收缩数据和日志 bn5 Su=]
DBCC SHRINKDB 25?6gu*Z
DBCC SHRINKFILE ICQKP1WFp
3、压缩数据库 .q>iXE_c
dbcc shrinkdatabase(dbname) Lf&kv7Wj
4、转移数据库给新用户以已存在用户权限 $&td=OK
exec sp_change_users_login 'update_one','newname','oldname' VPo".BvG6
go o+'6`g'8
5、检查备份集 f:}
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' sgFEK[w.y
6、修复数据库 k,*XG$2h
ALTER DATABASE [dvbbs] SET SINGLE_USER *2l7f`K
GO !Vk^TFt`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK KWHY4
GO 7[)E>XRE
ALTER DATABASE [dvbbs] SET MULTI_USER 4WB0Pt{
GO ktIFI`@w)
7、日志清除 M= (u]%\
SET NOCOUNT ON "y}5;9#,
DECLARE @LogicalFileName sysname, `c$V$/IT
@MaxMinutes INT, 2^7`mES
@NewSize INT AK4t\D)K1
USE tablename -- 要操作的数据库名 guR/\z$D@C
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 TLH1>pY&
@MaxMinutes = 10, -- Limit on time allowed to wrap log. eR>oq,
@NewSize = 1 -- 你想设定的日志文件的大小(M) Bzf^ivT3L
-- Setup / initialize >(<f 0
DECLARE @OriginalSize int $&c*'3
SELECT @OriginalSize = size _[BP0\dPW
FROM sysfiles hZb_P\1X
WHERE name = @LogicalFileName /n&&Um\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + :2`e(+Uz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + jP.dDYc
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 8s@3hXD&
FROM sysfiles >t+P(*u
WHERE name = @LogicalFileName nw<uyaU-t
CREATE TABLE DummyTrans [a(#1
(DummyColumn char (8000) not null) xmoxZW:
DECLARE @Counter INT, :3 mh@[V
@StartTime DATETIME, +}AI@+
@TruncLog VARCHAR(255) "AqB$^S9t
SELECT @StartTime = GETDATE(), 8oGRLYU N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $??I/6
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 6 u6x
EXEC (@TruncLog) A#,ZUOPGH
-- Wrap the log if necessary. ;'1d1\wiDQ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired V7/Rby Q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *un^u-;
AND (@OriginalSize * 8 /1024) > @NewSize u3D)M%e
BEGIN -- Outer loop. H5an%kU|j
SELECT @Counter = 0 sLk-x\P]|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \;Weizq5
BEGIN -- update er\|i. Y
INSERT DummyTrans VALUES ('Fill Log') L~3Pm%{@A
DELETE DummyTrans 0jfuBj5!
SELECT @Counter = @Counter + 1 4+tEFxvX&
END 4qa.1j(R/
EXEC (@TruncLog) U<XG{<2
END "dlVk~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + /-s6<e!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |s_GlJV.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' E qiY\/S
FROM sysfiles #dHa,HUk
WHERE name = @LogicalFileName yhJ@(tu.Gd
DROP TABLE DummyTrans :4|4 =mkr
SET NOCOUNT OFF !)$Zp\Sg
8、说明:更改某个表 XWw804ir
exec sp_changeobjectowner 'tablename','dbo' Zd+bx*rD
9、存储更改全部表 (@YG~0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %TqC/c
@OldOwner as NVARCHAR(128), 6eCCmIdaM
@NewOwner as NVARCHAR(128) <UCl@5g&
AS dh\P4
DECLARE @Name as NVARCHAR(128) =(^3}x
DECLARE @Owner as NVARCHAR(128) l^}c!
DECLARE @OwnerName as NVARCHAR(128) b,@/!ia
DECLARE curObject CURSOR FOR I-)4YQI
select 'Name' = name, HaYo!.(Fv
'Owner' = user_name(uid) ;*J
from sysobjects xSu >
where user_name(uid)=@OldOwner ,r}6iFu
order by name ,,r>,Xq6
OPEN curObject 7:@'B|
FETCH NEXT FROM curObject INTO @Name, @Owner AXB7oV,xt
WHILE(@@FETCH_STATUS=0) Ys7]B9/1O
BEGIN y{Q
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if @Owner=@OldOwner I1J-)R+
begin AZ<=o
set @OwnerName = @OldOwner + '.' + rtrim(@Name) PvL[e"p
exec sp_changeobjectowner @OwnerName, @NewOwner H?w6C):]
end Y/oHu@
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-- select @name,@NewOwner,@OldOwner +C)~bb*
FETCH NEXT FROM curObject INTO @Name, @Owner /wv0i3_e
END <3
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close curObject jiGTA:v
deallocate curObject EM_d8o)`B
GO gM]:Ma
10、SQL SERVER中直接循环写入数据 d zMb5puH
declare @i int MK*r+xfSae
set @i=1 Q{/Ef[(a@
while @i<30 TqQ[_RKg2
begin Ort(AfW
insert into test (userid) values(@i) +7a6*;\ y
set @i=@i+1 76SXJ9@x
end \7_y%HR
小记存储过程中经常用到的本周,本月,本年函数 @VI@fN
Dateadd(wk,datediff(wk,0,getdate()),-1) @6]JIJE
Dateadd(wk,datediff(wk,0,getdate()),6) SrJE_~i
Dateadd(mm,datediff(mm,0,getdate()),0) Ul# r
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) N>E_%]C h
Dateadd(yy,datediff(yy,0,getdate()),0) >mkFV@`
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) jWgX_//!
上面的SQL代码只是一个时间段 H/Jbk*Q
Dateadd(wk,datediff(wk,0,getdate()),-1) +|f@^-
Dateadd(wk,datediff(wk,0,getdate()),6) ?A0)L27UE&
就是表示本周时间段. O0:q;<>z
下面的SQL的条件部分,就是查询时间段在本周范围内的: |BYRe1l6l
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ykJ>*z
而在存储过程中 C,zohlpC
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )B*t
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) kf9X$d6