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。 Dn!V)T
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一、基础 bsVOO9.4-
1、说明:创建数据库 L2tmo-]nw
CREATE DATABASE database-name % QkvBg*
2、说明:删除数据库 69L&H!<i:
drop database dbname r73Xh"SL
3、说明:备份sql server c" HCc]
--- 创建 备份数据的 device @UBp;pb}=h
USE master 4QDzG~N4)|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' AS
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--- 开始 备份 v]sGdZ(6-
BACKUP DATABASE pubs TO testBack 3M`J.>
4、说明:创建新表 T[J_/DE@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) yK;I<8+>_
根据已有的表创建新表: X}
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A:create table tab_new like tab_old (使用旧表创建新表) !<'R%<E3Q
B:create table tab_new as select col1,col2... from tab_old definition only D':A-E
5、说明:删除新表 *n\qV*|6bI
drop table tabname )nV x 2m4
6、说明:增加一个列 U)6JJv
Alter table tabname add column col type ]5CFL$_Q{
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。 dY^~^<{Lj
7、说明:添加主键: Alter table tabname add primary key(col) MDt4KD+bZ
说明:删除主键: Alter table tabname drop primary key(col) .d,Zx
8、说明:创建索引:create [unique] index idxname on tabname(col....) To95WG7G
删除索引:drop index idxname 2Ev,dWV
注:索引是不可更改的,想更改必须删除重新建。 +!wc(N[(2
9、说明:创建视图:create view viewname as select statement xDS9gGr
删除视图:drop view viewname =X):Zi
10、说明:几个简单的基本的sql语句 b1"wQM9
选择:select * from table1 where 范围 AmFHn
插入:insert into table1(field1,field2) values(value1,value2) &aU+6'+QXB
删除:delete from table1 where 范围 8iB}a\]B
更新:update table1 set field1=value1 where 范围 c=CXj3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! OYkd?LN
排序:select * from table1 order by field1,field2 [desc] 1OKJE(T
总数:select count as totalcount from table1 L M[<?`%p
求和:select sum(field1) as sumvalue from table1 VB%xV
平均:select avg(field1) as avgvalue from table1 0rj* SC_
最大:select max(field1) as maxvalue from table1 %8/$CR
最小:select min(field1) as minvalue from table1 x(Z@R\C-a
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11、说明:几个高级查询运算词 'AU!xG6OQ
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A: UNION 运算符 Z9y:}:j"
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 {zcjTJ=Zt8
B: EXCEPT 运算符 ZBWe,Xvq
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 yO)Qg*r
C: INTERSECT 运算符 ]
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 bE{`g]C5
注:使用运算词的几个查询结果行必须是一致的。 l;fH5z
12、说明:使用外连接 c1f6RCu$b
A、left outer join: '_%Jw:4k
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。 PC5FfX
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 P:o<kRj1
B:right outer join: 6 9Cxh
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。 P#C`/%$S
C:full outer join: *Bj G3Jc5
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 q]aRJ`9f
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二、提升 I <7K^j+5:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) jdzV&
法一:select * into b from a where 1<>1 d:aQlW;}
法二:select top 0 * into b from a \GN5Sy]r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3ml|`S
insert into b(a, b, c) select d,e,f from b;
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) utXcfKdt
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 e:]$UAzp
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !WmpnPr1
4、说明:子查询(表名1:a 表名2:b) 9z?F_=PB!
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) K':f!sZ&2
5、说明:显示文章、提交人和最后回复时间 k dqH36&<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @NF8?>!
6、说明:外连接查询(表名1:a 表名2:b) f{J7a1 `_
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 0
7、说明:在线视图查询(表名1:a ) pfG:PrZ
select * from (SELECT a,b,c FROM a) T where t.a > 1; YY9q'x,w
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 (.cT<(TB
select * from table1 where time between time1 and time2 d0,I] "
select a,b,c, from table1 where a not between 数值1 and 数值2 U8dwb
9、说明:in 的使用方法 S70ERRk
select * from table1 where a [not] in ('值1','值2','值4','值6') A,osrv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 q:'(1y~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #KwFrlZ
11、说明:四表联查问题: 9o6y7hEQy
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 ..... 5D#*lMSP"'
12、说明:日程安排提前五分钟提醒 Ny#%7%(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 DmYm~hzJ
13、说明:一条sql 语句搞定数据库分页 `i}\k
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 W$&Q.Z
14、说明:前10条记录 6 B
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select top 10 * form table1 where 范围 Oj2[(7mO/
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.) TCYnErqk
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (]JJ?aAF
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 >wn&+%i&
(select a from tableA ) except (select a from tableB) except (select a from tableC) rtI4W
17、说明:随机取出10条数据 F-nt7l
select top 10 * from tablename order by newid() T F'ssD
18、说明:随机选择记录 5]{YERa'
select newid() C'Ymz`iQ
19、说明:删除重复记录 v-kH7H"z
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ~ M"[FYw[
20、说明:列出数据库里所有的表名 2aG<^3
select name from sysobjects where type='U' P>H'od
21、说明:列出表里的所有的 Av'H(qB\K
select name from syscolumns where id=object_id('TableName') Zqao4
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。 ecb[m2z
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 V3-LVgM%
显示结果: a'|0e]
type vender pcs k;)L-ge9
电脑 A 1 D -jew &B
电脑 A 1 ,UP6.C14
光盘 B 2 mHP1.Z`
光盘 A 2 :+YFO.7
手机 B 3 b`2~
手机 C 3 pyN PdEy
23、说明:初始化表table1 c/s'&gG33z
TRUNCATE TABLE table1 k`?n("j
24、说明:选择从10到15的记录 eRf8'-"#-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2XE4w# [j
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三、技巧 Bg3^BOT
1、1=1,1=2的使用,在SQL语句组合时用的较多 @=9QV3D
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W&"FejD
如: `1P
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if @strWhere !='' WN0^hDc-
begin 0ul2rZc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Pvtf_Qo^
end Z/0M9 Q%
else >Nov9<p
begin m$4 Gm(Up
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' FnCHbPlb
end E$G8-
我们可以直接写成 &1I0i[R
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 29E^]IL?
2、收缩数据库 CV` I.
--重建索引 <"t >!I
DBCC REINDEX g><sZqj8tt
DBCC INDEXDEFRAG W6)A":`
--收缩数据和日志 "];19]x6q
DBCC SHRINKDB ie_wJ=s
DBCC SHRINKFILE #):FXB$a
3、压缩数据库 /g_}5s-Z
dbcc shrinkdatabase(dbname) ?e BN_a,r6
4、转移数据库给新用户以已存在用户权限 55#H A?cR
exec sp_change_users_login 'update_one','newname','oldname' uto4bs:
go Kp"o0fh<9
5、检查备份集 +pE-Yn`YS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' O9qEKW)a
6、修复数据库 j3FDGDrg
ALTER DATABASE [dvbbs] SET SINGLE_USER (BJs6":BFe
GO ON$u581 y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >FY`xl\m}<
GO Q%85,L^ U
ALTER DATABASE [dvbbs] SET MULTI_USER lwK Au!l
GO 4WNWn#M
7、日志清除 $,R|$0B7
SET NOCOUNT ON O=yUAAD$
DECLARE @LogicalFileName sysname, Ly^r8I
@MaxMinutes INT, z- ()7WY
@NewSize INT k:c)|2
USE tablename -- 要操作的数据库名 Oh|Hy/&6W
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 j/9'L^]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. a.q=
@NewSize = 1 -- 你想设定的日志文件的大小(M) 8&3G|m1-2
-- Setup / initialize m:'fk;khN
DECLARE @OriginalSize int N!,@}s
SELECT @OriginalSize = size wL}=$DN
FROM sysfiles TEY%OIzU+
WHERE name = @LogicalFileName M*t{?o/t;
SELECT 'Original Size of ' + db_name() + ' LOG is ' + [1N*mY;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2r1.,1
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rHP5;j<]
FROM sysfiles chxO*G
WHERE name = @LogicalFileName <Q%\pAP}b
CREATE TABLE DummyTrans (pAGS{{
(DummyColumn char (8000) not null) l2$6ojpo
DECLARE @Counter INT, Peb;XI
@StartTime DATETIME, dC)@v]#h
@TruncLog VARCHAR(255) GUMO;rZs
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' z0c_&@uj*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) rR/PnVup
EXEC (@TruncLog) G6L'RP
-- Wrap the log if necessary. aj1Zi3h
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired o@"H3
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 2jA-y!(e
AND (@OriginalSize * 8 /1024) > @NewSize JEj.D=@[
BEGIN -- Outer loop. D;m>9{=
SELECT @Counter = 0 |o6B:NH,rg
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 58WL8xu
BEGIN -- update >8EIm
INSERT DummyTrans VALUES ('Fill Log') ,\ov$biL
DELETE DummyTrans bKiV<&Z5d
SELECT @Counter = @Counter + 1 w;)@2}
END 8M!If
EXEC (@TruncLog) NKh 8'=S
END U@DIO/C,m`
SELECT 'Final Size of ' + db_name() + ' LOG is ' + H htAD Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %I?uO(
@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' :H3qa2p
FROM sysfiles @=:( b"Sg
WHERE name = @LogicalFileName V
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DROP TABLE DummyTrans y 1z4qSeM
SET NOCOUNT OFF 1^$ vmULj
8、说明:更改某个表 r6JdF!\d
exec sp_changeobjectowner 'tablename','dbo' Q/L:0ovR
9、存储更改全部表 :IvKxOv
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch qauk,t
@OldOwner as NVARCHAR(128), h9$Ov`N(%
@NewOwner as NVARCHAR(128) 3y<;fdS7
AS !bRoNP
DECLARE @Name as NVARCHAR(128) ?X~Keb
DECLARE @Owner as NVARCHAR(128) 94\k++kc
DECLARE @OwnerName as NVARCHAR(128) 83e{rcs
DECLARE curObject CURSOR FOR p%ek)tT
select 'Name' = name, +O2T%
'Owner' = user_name(uid) @LqLtr@A
from sysobjects CB:G4VqOT
where user_name(uid)=@OldOwner ?u/RQ 1
order by name 9+_SG/@
OPEN curObject -ich N/U]s
FETCH NEXT FROM curObject INTO @Name, @Owner v?vm-e
WHILE(@@FETCH_STATUS=0) DavpjwSn
BEGIN :[A>O(
if @Owner=@OldOwner )w=ehjV^m
begin *\L\Bzm
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Y?ouB
exec sp_changeobjectowner @OwnerName, @NewOwner ?%d]iTZE
end :>+}|(v
-- select @name,@NewOwner,@OldOwner OLg=kF[[
FETCH NEXT FROM curObject INTO @Name, @Owner :VGvL"Kro
END \ ?sM
close curObject 1U^;fqvja
deallocate curObject TldqF BX
GO Q!9AxM2K
10、SQL SERVER中直接循环写入数据 D% v{[KY
declare @i int T 5$db-^
set @i=1 ^Q0%_V,
while @i<30 1<IF@__
begin 3+ JkV\AF
insert into test (userid) values(@i) &>,c..Ke
set @i=@i+1 Ahv %Q%m%2
end -T$%MX
小记存储过程中经常用到的本周,本月,本年函数 Q+YYj
Dateadd(wk,datediff(wk,0,getdate()),-1) dn!#c=
Dateadd(wk,datediff(wk,0,getdate()),6) ]rY:C "#
Dateadd(mm,datediff(mm,0,getdate()),0) \jH^OXxb
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) gn4+$ f~w
Dateadd(yy,datediff(yy,0,getdate()),0) mO%F {'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .W>LEz'
上面的SQL代码只是一个时间段 \W:~;GMeD
Dateadd(wk,datediff(wk,0,getdate()),-1) _!2bZ:emG
Dateadd(wk,datediff(wk,0,getdate()),6) XA PqRJ*Z
就是表示本周时间段. mhpaPin*JS
下面的SQL的条件部分,就是查询时间段在本周范围内的: Vz[tgb]-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) X+dLk(jI`u
而在存储过程中 1g<jr.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )i|0Ubn[|
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Jga;nrU