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。 P&3Z,f0
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一、基础 ;|a,1#x
1、说明:创建数据库 `Z)]mH\X
CREATE DATABASE database-name ,lsoxl
2、说明:删除数据库 zQPQP`
drop database dbname oM<Y o%n
3、说明:备份sql server )p?p39>h
--- 创建 备份数据的 device e\ Igc.
USE master LBCat=d<
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' *_Sx^`"X`l
--- 开始 备份 Z+3j>_Ss
BACKUP DATABASE pubs TO testBack vv 7T/C
4、说明:创建新表 "q<}#] u
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ysHmi{V~
根据已有的表创建新表: OVy ZyZ#
A:create table tab_new like tab_old (使用旧表创建新表) uaiCyh1:
B:create table tab_new as select col1,col2... from tab_old definition only .+.BNS
5、说明:删除新表 zJxO\
drop table tabname ZJZKCdT@
6、说明:增加一个列 R=/^5DZ}
Alter table tabname add column col type =&9x}4`;%
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。 !%8|R]d
7、说明:添加主键: Alter table tabname add primary key(col) +?&|p0
说明:删除主键: Alter table tabname drop primary key(col) pz
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8、说明:创建索引:create [unique] index idxname on tabname(col....) ,.Sd)JB'
删除索引:drop index idxname :\Pk>a
注:索引是不可更改的,想更改必须删除重新建。 8D)I~0\
9、说明:创建视图:create view viewname as select statement 6 2YT)/i3
删除视图:drop view viewname q-k~L\Ys
10、说明:几个简单的基本的sql语句 }\-"L/D?+
选择:select * from table1 where 范围 w%Bo7 'o)V
插入:insert into table1(field1,field2) values(value1,value2) 8dBG ZwyET
删除:delete from table1 where 范围 MhaoD5*9
更新:update table1 set field1=value1 where 范围 c;M&;'#x
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Pl9Ky(Q`V
排序:select * from table1 order by field1,field2 [desc] "{1SDbwmMo
总数:select count as totalcount from table1 Ho_ 2zx:8b
求和:select sum(field1) as sumvalue from table1 Z` ;.62S
平均:select avg(field1) as avgvalue from table1 6Z:swgi6&
最大:select max(field1) as maxvalue from table1 s\Zp/-Q
最小:select min(field1) as minvalue from table1 :)P Aj
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11、说明:几个高级查询运算词 cD!yd^QE
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A: UNION 运算符 @a[Y[FS
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。 .5ItH^
B: EXCEPT 运算符 s{30#^1R
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。 0}:wM':G
C: INTERSECT 运算符 |K7zN\
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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。 8B|qNf `Yi
注:使用运算词的几个查询结果行必须是一致的。 sy
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12、说明:使用外连接 "c'K8,+?
A、left outer join: %XUV[L}
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。 b+6%Mu}o
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 `H#G/zOr
B:right outer join: AVR=\ qR
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。 FlqE!6[[
C:full outer join: #&oL iz=hZ
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。 -weCdTY`X
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二、提升 VvS ^f
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) s/"l ?d
法一:select * into b from a where 1<>1 / }tMb
法二:select top 0 * into b from a ^kF-mM=
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }2 X"
insert into b(a, b, c) select d,e,f from b; *pZhwO!D
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) kv)IG$S0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 LY? `+/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. H:x{qS4Si
4、说明:子查询(表名1:a 表名2:b) ivi,/~L
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) iuxS=3lT"K
5、说明:显示文章、提交人和最后回复时间 r^jiK\*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b A=+
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6、说明:外连接查询(表名1:a 表名2:b) ,[j'OyR
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;`(l)X+7
7、说明:在线视图查询(表名1:a ) 'T_Vm%\)
select * from (SELECT a,b,c FROM a) T where t.a > 1; %^){)#6w
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 /Ayo78Pi
select * from table1 where time between time1 and time2 XXe?@w2{
select a,b,c, from table1 where a not between 数值1 and 数值2 Pv>W`/*_,s
9、说明:in 的使用方法 *w/})Y3^
select * from table1 where a [not] in ('值1','值2','值4','值6') SZ*Nr=X
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ahnQq9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ":G\
11、说明:四表联查问题: j1sZRl)D
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 ..... }5I+VY7a
12、说明:日程安排提前五分钟提醒 EU0b>2n4
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 2/coa+Qkv]
13、说明:一条sql 语句搞定数据库分页 GmJ4AYEP
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 ~dpU DF
14、说明:前10条记录 k|-P&g
select top 10 * form table1 where 范围 W
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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.) {~lVe GBp
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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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 b_p/ 1W:
(select a from tableA ) except (select a from tableB) except (select a from tableC) o(w xu)
17、说明:随机取出10条数据 HLa3lUo
select top 10 * from tablename order by newid() (
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18、说明:随机选择记录 FU~xKNr
select newid() &.ENcEic
19、说明:删除重复记录 aSy^(WN8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wk'12r6=(-
20、说明:列出数据库里所有的表名 DviR D[+q"
select name from sysobjects where type='U' Ns*&;x9
21、说明:列出表里的所有的 aJmSagr69C
select name from syscolumns where id=object_id('TableName') Rb8wq.LqD
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。 8pEiU/V
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 6H)T=Z|
显示结果: v_7?Zik8E
type vender pcs [J`%iU
电脑 A 1 O8 \dMb
电脑 A 1 =jWcD{;1I}
光盘 B 2 63EwV p/|
光盘 A 2 ?mRGFS
手机 B 3 I1Jo 8s
手机 C 3 #KOr-Yg|U
23、说明:初始化表table1 LZ?z5U:
TRUNCATE TABLE table1 ";PW#VHC
24、说明:选择从10到15的记录 .*3.47O
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }K8W%h<3S
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三、技巧 {[<o)k .A
1、1=1,1=2的使用,在SQL语句组合时用的较多 afOix"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, tE~OWjL
如: ?$>#FKrt
if @strWhere !='' 4=T.rVS[
begin ^>3q@,C]c
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sFvu@Wm'7W
end 2Gw2k8g&
else @`,~d{ziF
begin zFn!>Tqe
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5Q9nJC{'NN
end #2XX [d%
我们可以直接写成 _~=qByD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .o._`"V
2、收缩数据库 h
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--重建索引 6w )mo)<X
DBCC REINDEX D #`o
DBCC INDEXDEFRAG gHB*u!w7Z
--收缩数据和日志 8`0/?MZ)
DBCC SHRINKDB rQuozbBb
DBCC SHRINKFILE ./iC
3、压缩数据库 b#17N2xkT
dbcc shrinkdatabase(dbname) u@ "nVHgMJ
4、转移数据库给新用户以已存在用户权限 a
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exec sp_change_users_login 'update_one','newname','oldname' )yOdRRP
go (pU@$H
5、检查备份集 3
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' re$xeq\1P?
6、修复数据库 $CXMeY{tOo
ALTER DATABASE [dvbbs] SET SINGLE_USER (iT?uMRz
GO EINjI:/D
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK uaX#nn?ws
GO ^uDNArDmj5
ALTER DATABASE [dvbbs] SET MULTI_USER OIqisQ7ZB
GO CXe2G5
7、日志清除 C`++r>
SET NOCOUNT ON ['*{f(AI
DECLARE @LogicalFileName sysname, I"4Lma
@MaxMinutes INT, 3>+9Rru
@NewSize INT r&MHww1i
USE tablename -- 要操作的数据库名 Q7~9~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 w,,QXJe{Z_
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N 9.$--X}D
@NewSize = 1 -- 你想设定的日志文件的大小(M) vq.~8c1
-- Setup / initialize ;?*`WB
DECLARE @OriginalSize int lU}y%J@
SELECT @OriginalSize = size QO-R>
FROM sysfiles xYg G
WHERE name = @LogicalFileName _`H2CXGg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + XVlZ:kz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + h0=Q .Yz6
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (F<VcB
FROM sysfiles aT]G&bR?
WHERE name = @LogicalFileName n{b(~eL?
CREATE TABLE DummyTrans ;j#(%U]Vp
(DummyColumn char (8000) not null) _0v+g1x
DECLARE @Counter INT, |UGmIm%
@StartTime DATETIME, iut[?#f^
@TruncLog VARCHAR(255) iPD5
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SELECT @StartTime = GETDATE(), `Wes!>Vh!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' wU9H=w^
DBCC SHRINKFILE (@LogicalFileName, @NewSize) hZ#ydI|
EXEC (@TruncLog) Q?Y\WD
-- Wrap the log if necessary. 1feZ`P;
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =)2sehU/
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) \e=Iw"yd
AND (@OriginalSize * 8 /1024) > @NewSize n O^m
BEGIN -- Outer loop. R.Plfm06Ue
SELECT @Counter = 0 i>]1E^yF
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) wfecM(
BEGIN -- update 8Moe8X#3
INSERT DummyTrans VALUES ('Fill Log') FR7DuH/f)
DELETE DummyTrans DR d|m<Z
SELECT @Counter = @Counter + 1 Xf4
END #dvH0LX?
EXEC (@TruncLog) )*b
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END *Y4[YnkPE
SELECT 'Final Size of ' + db_name() + ' LOG is ' + FuWMVT`Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^-*q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' l@h|os
FROM sysfiles P
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WHERE name = @LogicalFileName \o&\r)FX
DROP TABLE DummyTrans c7E|GZ2Hc
SET NOCOUNT OFF sULCYiT|Hn
8、说明:更改某个表 g}cb>'=={
exec sp_changeobjectowner 'tablename','dbo' #[Z1W8e
9、存储更改全部表 (P+TOu-y\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch CJDnHuozc
@OldOwner as NVARCHAR(128), jo7`DDb
@NewOwner as NVARCHAR(128) ;2NJkn9t
AS %gd{u\h^
DECLARE @Name as NVARCHAR(128) jGeil
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DECLARE @Owner as NVARCHAR(128) 4(h19-V
DECLARE @OwnerName as NVARCHAR(128) ?yfw3s
DECLARE curObject CURSOR FOR gB&8TE~Y
select 'Name' = name, t#fbagTON
'Owner' = user_name(uid) k3pY3TA@w+
from sysobjects 0wh4sKm[X
where user_name(uid)=@OldOwner d){o#@
order by name YqJ
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OPEN curObject Gr&)5hm$
FETCH NEXT FROM curObject INTO @Name, @Owner WN5`zD$
WHILE(@@FETCH_STATUS=0) b3h3$kIYN
BEGIN E`"<t:RzF
if @Owner=@OldOwner c}QWa"\2n
begin 3:S>MFRn.3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) hS( )OY
exec sp_changeobjectowner @OwnerName, @NewOwner a/k0(
end csEF^T-
-- select @name,@NewOwner,@OldOwner &D/@H1fBe
FETCH NEXT FROM curObject INTO @Name, @Owner }o'WR'LX
END ]12ypcf
close curObject xT]|78h$
deallocate curObject Pl>BTo>p'
GO dN8@ 0AMSf
10、SQL SERVER中直接循环写入数据 LU=<?"N6
declare @i int *hk8[
set @i=1 c,v?2*<
while @i<30 !xIK<H{*
begin 2;v1YKY
insert into test (userid) values(@i) cC NyW2'
set @i=@i+1 &F8N$H
end bh[`uRC}
小记存储过程中经常用到的本周,本月,本年函数 T3JM8
Dateadd(wk,datediff(wk,0,getdate()),-1) =SY`Xkj[
Dateadd(wk,datediff(wk,0,getdate()),6) z-J?x-<
Dateadd(mm,datediff(mm,0,getdate()),0) #835$vOe
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 37F&s
Dateadd(yy,datediff(yy,0,getdate()),0) h@^d
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))
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上面的SQL代码只是一个时间段 ^#V7\;v$G
Dateadd(wk,datediff(wk,0,getdate()),-1) JKXb$
Dateadd(wk,datediff(wk,0,getdate()),6) ~!PaBS3A
就是表示本周时间段. Xcy Xju#"p
下面的SQL的条件部分,就是查询时间段在本周范围内的: c=^A3[AM
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) wa)E.(x
而在存储过程中 [!<W{ ($5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) M9t`w-@_w
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) /^2&@P7