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。 3#n_?-
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一、基础 =?5]()'*n
1、说明:创建数据库 b.OsiT;_j
CREATE DATABASE database-name h<h%*av|
2、说明:删除数据库 a)!o @
drop database dbname p
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3、说明:备份sql server #]-SJWf3
--- 创建 备份数据的 device i:dR\|B
USE master f'F?MINJP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Q*GN`07@?d
--- 开始 备份 mwO6g~@`
BACKUP DATABASE pubs TO testBack %J}xg^+f
4、说明:创建新表 *j|~$e}C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3h]g}&k
根据已有的表创建新表: mupT<_Y
A:create table tab_new like tab_old (使用旧表创建新表) ~EW(Gs!=C
B:create table tab_new as select col1,col2... from tab_old definition only t"sBPLU\
5、说明:删除新表 a6ekG YW
drop table tabname }czrj%6
6、说明:增加一个列 l&[O
Alter table tabname add column col type
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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。 gZVc 5u<
7、说明:添加主键: Alter table tabname add primary key(col) &L3M]
说明:删除主键: Alter table tabname drop primary key(col) ]|#+zx|/D
8、说明:创建索引:create [unique] index idxname on tabname(col....) {aZ0;
删除索引:drop index idxname RCJ|P~*
注:索引是不可更改的,想更改必须删除重新建。 IM*y|UHt
9、说明:创建视图:create view viewname as select statement g/4[N{Xf
删除视图:drop view viewname T%+#xl
10、说明:几个简单的基本的sql语句 \-E^lIVF
选择:select * from table1 where 范围 V( }:=eK
插入:insert into table1(field1,field2) values(value1,value2) pG_;$8Hc
删除:delete from table1 where 范围 z xEL+ P
更新:update table1 set field1=value1 where 范围 7o\@>rNWP
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! y4yhF8E>;U
排序:select * from table1 order by field1,field2 [desc] ^"E^zHM(
总数:select count as totalcount from table1 UB@Rs|)
求和:select sum(field1) as sumvalue from table1 ip\sXVR
平均:select avg(field1) as avgvalue from table1 )w em|:H
最大:select max(field1) as maxvalue from table1 rDtY[
最小:select min(field1) as minvalue from table1 K&u_R
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11、说明:几个高级查询运算词 MyOd,vU
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A: UNION 运算符 ]dVGUG8
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 :x3QRF
B: EXCEPT 运算符 t}_r]E,{u
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 cx,+k]9D
C: INTERSECT 运算符 39c2pV[
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 g_E$=j92v
注:使用运算词的几个查询结果行必须是一致的。 _=>He=v/
12、说明:使用外连接 P-[-pi@
A、left outer join: #I.+aV+2oQ
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。 u$z`
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c &md`$a/
B:right outer join: + SzU
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。 RIR\']WN
C:full outer join: x%=si[P
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。 Xc++b|k
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二、提升 yNBQGSH
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) S
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法一:select * into b from a where 1<>1 ]Ee?6]bN
法二:select top 0 * into b from a
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^^u5*n+5
insert into b(a, b, c) select d,e,f from b; y
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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) _{ue8kGt
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,O5NLg-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~i= _J3'
4、说明:子查询(表名1:a 表名2:b) I@\lN&HC
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) BkAm/R
5、说明:显示文章、提交人和最后回复时间 pp?D7S
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b m[osg< CR_
6、说明:外连接查询(表名1:a 表名2:b) TvoyZW\?w
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c DDQx
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7、说明:在线视图查询(表名1:a ) E,Z$pKL?
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5PCqYN(:B
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 `?H]h"{7Q
select * from table1 where time between time1 and time2 L<c4kw
select a,b,c, from table1 where a not between 数值1 and 数值2 t|?ez4/{z
9、说明:in 的使用方法 j a[Et/r
select * from table1 where a [not] in ('值1','值2','值4','值6') @/~omg}R
10、说明:两张关联表,删除主表中已经在副表中没有的信息 1dY}\Sp
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) PN%zIkbo
11、说明:四表联查问题: ^S<Y>Nm]
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 ..... ho{*Cjv
12、说明:日程安排提前五分钟提醒 DPY}?dC
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 YRk(u7:0
13、说明:一条sql 语句搞定数据库分页 D>r&}6<
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 &A/]pi-\
14、说明:前10条记录 <\y@*fg+
select top 10 * form table1 where 范围 ,]C;sN%~}
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.) nbp=PzZy
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "V7K SO
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 @&!ZZ
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(select a from tableA ) except (select a from tableB) except (select a from tableC) ;<Sd~M4f
17、说明:随机取出10条数据 hR
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select top 10 * from tablename order by newid() CZe ]kXNv
18、说明:随机选择记录 )CYGQMK
select newid() w_c"@CjkE
19、说明:删除重复记录 X56q-|
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wo}H'Q}Hj
20、说明:列出数据库里所有的表名 }v;V=%N+v
select name from sysobjects where type='U' ~Gp[_ %K
21、说明:列出表里的所有的 yf)%%&
select name from syscolumns where id=object_id('TableName') UXz<)RvB
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。 8,Z_{R#|
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 Tb}4wLu
显示结果: Rh2+=N<X
type vender pcs OKZV{Gja
电脑 A 1 PNhe
电脑 A 1 GMx&y2. Z
光盘 B 2 ;>hO+Wo
光盘 A 2 `RT>}_j
手机 B 3 iXkF1r]i
手机 C 3 qbr$>xH
23、说明:初始化表table1 ^6x%*/l|
TRUNCATE TABLE table1 K g*Q
24、说明:选择从10到15的记录 NX.6px17
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc GKqm&/M*=
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三、技巧 + 480 l}
1、1=1,1=2的使用,在SQL语句组合时用的较多 , pfG
"where 1=1" 是表示选择全部 "where 1=2"全部不选, %Xg4b6<9
如: R{4^t97wH{
if @strWhere !='' P:S .~Jq
begin uc{Ihw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere hFUlNJ
end 5~U/
else 2W(s(-hD
begin I|!OY`ko
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8%mu8l
end h&iC;yj=
我们可以直接写成 P5V}#;v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \7eUw,~Q>
2、收缩数据库 K3&qq[8.e
--重建索引 c):/!Q
DBCC REINDEX #zy:a%
DBCC INDEXDEFRAG Es`Px_k
--收缩数据和日志 Wb_J(!da
DBCC SHRINKDB ~_)^X
DBCC SHRINKFILE @;4zrzQi7
3、压缩数据库 <}Vrl`?h
dbcc shrinkdatabase(dbname) r6Dz;uz
4、转移数据库给新用户以已存在用户权限 rKc9b<Ir
exec sp_change_users_login 'update_one','newname','oldname' s^TZXCyF o
go {?0lBfB"
5、检查备份集 3%|&I:tI
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ~/U1xk%
6、修复数据库 [aLI
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ALTER DATABASE [dvbbs] SET SINGLE_USER @bLy,Xr&
GO B@))8.h]
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK t+
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GO I{&[[7H
ALTER DATABASE [dvbbs] SET MULTI_USER iVr J Q
GO v~C
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7、日志清除 :4w ?#
SET NOCOUNT ON L{\8!51L
DECLARE @LogicalFileName sysname, Hio0HL-
@MaxMinutes INT, S+6.ZZ9c
@NewSize INT ,THw"bm
USE tablename -- 要操作的数据库名 {uFO/
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 B mb0cFQ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. V &T~zh1
@NewSize = 1 -- 你想设定的日志文件的大小(M) m7V/zne
-- Setup / initialize w.o@7|B1N
DECLARE @OriginalSize int I][*j
SELECT @OriginalSize = size Lb-OsKU
FROM sysfiles ]5cT cX;Z#
WHERE name = @LogicalFileName ?UR0:f:}oc
SELECT 'Original Size of ' + db_name() + ' LOG is ' + }v{LRRi
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + $wa{~'
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Vp\,CuQ
FROM sysfiles S13nL^=i
WHERE name = @LogicalFileName ^DLfY-F+j
CREATE TABLE DummyTrans 6|=f$a
(DummyColumn char (8000) not null) +=h:Vb8
DECLARE @Counter INT, pllGB6X
@StartTime DATETIME, d1T!+I
@TruncLog VARCHAR(255) RP|`HkP-2
SELECT @StartTime = GETDATE(), DCa^
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -i|}m++
DBCC SHRINKFILE (@LogicalFileName, @NewSize) cVpp-Z|s8
EXEC (@TruncLog) IP pN@
-- Wrap the log if necessary. y.k~Y0
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !BF;
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^7*11%Q
AND (@OriginalSize * 8 /1024) > @NewSize >Tx?%nQ
BEGIN -- Outer loop. TX/Xt7#R:
SELECT @Counter = 0 ,p a {qne
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'Is kWgc
BEGIN -- update y^*~B(T{
INSERT DummyTrans VALUES ('Fill Log') %;'s4ly
DELETE DummyTrans .{^5X)
SELECT @Counter = @Counter + 1 9*wK@yEl
END 9FR5Jw>t
EXEC (@TruncLog) t@;p
END wlvgg
SELECT 'Final Size of ' + db_name() + ' LOG is ' + @HC Vmg:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ajT*/L!0_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .P]+? %&
FROM sysfiles @mBQ?;qlK
WHERE name = @LogicalFileName Y=KT eYW`
DROP TABLE DummyTrans UkC!1Jy
SET NOCOUNT OFF -2[a2^a'
8、说明:更改某个表 vr l-$ii
exec sp_changeobjectowner 'tablename','dbo' X?',n
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9、存储更改全部表 l)\! .X
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Fm 2AEs\
@OldOwner as NVARCHAR(128), +sA2WK]
@NewOwner as NVARCHAR(128) |df Pki{
AS 5qm`J,~k
DECLARE @Name as NVARCHAR(128) :Yl-w-oe
DECLARE @Owner as NVARCHAR(128) =nS3p6>rZ
DECLARE @OwnerName as NVARCHAR(128) ;'K5J9k
DECLARE curObject CURSOR FOR TdMruSY
select 'Name' = name, N+xP26D8
'Owner' = user_name(uid) WH} y"W
from sysobjects {P./==^0
where user_name(uid)=@OldOwner ^CX6&d
order by name e T{ 4{
OPEN curObject xC TML!H
FETCH NEXT FROM curObject INTO @Name, @Owner RqrdAkg
WHILE(@@FETCH_STATUS=0) P@B]
BEGIN reWot&;
if @Owner=@OldOwner 59A}}.@?m
begin )akoa,#%6c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) LL!Dx%JZ
exec sp_changeobjectowner @OwnerName, @NewOwner 8<.Oq4ku
end Il'fL'3
-- select @name,@NewOwner,@OldOwner t*u:hex
FETCH NEXT FROM curObject INTO @Name, @Owner +6\Zj)
END n\53w h@+
close curObject 4VSU8tK|N]
deallocate curObject Sm|6 %3
GO VA5xp]
10、SQL SERVER中直接循环写入数据 CTa57R
declare @i int oc`H}Wvn
set @i=1 t~XN}gMxw
while @i<30 yf+)6D -9n
begin oPM96
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insert into test (userid) values(@i) o*H<KaX
set @i=@i+1 bd-L`={j
end 7NGxa6wi
小记存储过程中经常用到的本周,本月,本年函数 i.m^/0!
Dateadd(wk,datediff(wk,0,getdate()),-1) 5;EvNu
Dateadd(wk,datediff(wk,0,getdate()),6) Q2gq}c~
Dateadd(mm,datediff(mm,0,getdate()),0) TeM|:o
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) QWYJ*
Dateadd(yy,datediff(yy,0,getdate()),0) 8 Z~EwY*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Lf&kv7Wj
上面的SQL代码只是一个时间段 bAMdI 5Zk?
Dateadd(wk,datediff(wk,0,getdate()),-1) e"<OELA
Dateadd(wk,datediff(wk,0,getdate()),6) L0o\J` :
就是表示本周时间段. ,zjv7$L
下面的SQL的条件部分,就是查询时间段在本周范围内的: ":ue-=&M
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) MTn{d
而在存储过程中 (<9u-HF#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4hj|cCrO