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。 6mEW*qp2F
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一、基础 z$-/yT"M
1、说明:创建数据库 ,I=ClmR
CREATE DATABASE database-name $X9Ban]
2、说明:删除数据库 X3]E8)645N
drop database dbname |.:O$/ Tt[
3、说明:备份sql server %>i7A?L
--- 创建 备份数据的 device mo#4jtCE
USE master pP?J(0Q~
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' T]EXm/
--- 开始 备份 Sct-,K%i
BACKUP DATABASE pubs TO testBack Vw9^otJu
4、说明:创建新表 *@G4i
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5G){7]P+r"
根据已有的表创建新表: v5wI?HE
A:create table tab_new like tab_old (使用旧表创建新表) l4F4o6:]n
B:create table tab_new as select col1,col2... from tab_old definition only =Gd[Qn83.%
5、说明:删除新表 *8/Q_w
drop table tabname 2{p`"xX
6、说明:增加一个列 \9se~tAl3
Alter table tabname add column col type jXi<ZJ
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。 ynM{hN.+ H
7、说明:添加主键: Alter table tabname add primary key(col) o^&;
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说明:删除主键: Alter table tabname drop primary key(col) T|ZZkNP|6
8、说明:创建索引:create [unique] index idxname on tabname(col....) I2j;9Qcz
删除索引:drop index idxname "MC&!AMv
注:索引是不可更改的,想更改必须删除重新建。 S97.O@V!$
9、说明:创建视图:create view viewname as select statement Z6>:k,-Ot
删除视图:drop view viewname )\^o<x2S
10、说明:几个简单的基本的sql语句 M=o,Sav5*
选择:select * from table1 where 范围 1a4QWGpq
插入:insert into table1(field1,field2) values(value1,value2) +@%9pbM"z
删除:delete from table1 where 范围 0 nWV1)Q0=
更新:update table1 set field1=value1 where 范围 rxa"ji!)
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! h#]}J}si
排序:select * from table1 order by field1,field2 [desc] <mY`<(bc
总数:select count as totalcount from table1 <?qmB}Y
求和:select sum(field1) as sumvalue from table1 J-?\,N1R7
平均:select avg(field1) as avgvalue from table1 N>ct`a)BD/
最大:select max(field1) as maxvalue from table1 z8Dn<h
最小:select min(field1) as minvalue from table1 !kASEjFz|f
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11、说明:几个高级查询运算词 l`I]eTo)^
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A: UNION 运算符 -&,NM
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。 x0lX6
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B: EXCEPT 运算符 fwsq:
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。 i'e^[oZ
C: INTERSECT 运算符 ;\<?LTp/r
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。 Z(as@gjH
注:使用运算词的几个查询结果行必须是一致的。 c_ygwO3.Q
12、说明:使用外连接 }lpcbm
A、left outer join: [p o+a@ %
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。 kOdS^-
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 =53LapTPJ
B:right outer join: gP(-Op
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。 @/$mZ]|T
C:full outer join: x;Gyo
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。 k}lx!Ck
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二、提升 BLaXp0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) &2xYG{Z
法一:select * into b from a where 1<>1 Jh466;
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法二:select top 0 * into b from a [0 &Lvx
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) lh#GD"^(w&
insert into b(a, b, c) select d,e,f from b; wkJB5i^<w
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) GV[%P
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 :!} zdeRJ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. lC_zSmT
4、说明:子查询(表名1:a 表名2:b) Cg{$$&_(Hj
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) FJ U)AjS~
5、说明:显示文章、提交人和最后回复时间 ^w&TTo(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )D[xY0Y~
6、说明:外连接查询(表名1:a 表名2:b) }7.q[ ^oF
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c EL}v>sC
7、说明:在线视图查询(表名1:a ) M;iaNL(
select * from (SELECT a,b,c FROM a) T where t.a > 1; *|E@81s#
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 [qZ4+xF,,
select * from table1 where time between time1 and time2 s}z,{Y$-t
select a,b,c, from table1 where a not between 数值1 and 数值2 X! 2|_
9、说明:in 的使用方法 }SN'*w@E
select * from table1 where a [not] in ('值1','值2','值4','值6') <}mT[;:"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @tj0Ir v
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +]
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11、说明:四表联查问题: ZcWl{e4
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Y}?@Pm drz
12、说明:日程安排提前五分钟提醒 n/|/Womr
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 epG;=\f}m`
13、说明:一条sql 语句搞定数据库分页 R3@iN&
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 _b5iR<f
14、说明:前10条记录 ZDDwh&h
select top 10 * form table1 where 范围 sQ)4kF&,
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) F`-[h)e.
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Z^~6pH\
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 %@xYg{
(select a from tableA ) except (select a from tableB) except (select a from tableC) KdR&OBm
17、说明:随机取出10条数据 f:UN~z'yr
select top 10 * from tablename order by newid() GecXM Aa:2
18、说明:随机选择记录 ^Q OvK>W<
select newid() FN,uD:a
19、说明:删除重复记录 <Ihn1?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <bjy<98LT
20、说明:列出数据库里所有的表名 .N'UnKz
select name from sysobjects where type='U' |1<Z3\+_/
21、说明:列出表里的所有的 ^CE:?>a$
select name from syscolumns where id=object_id('TableName') *ap#*}r!Nk
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。 [`b{eLCFX]
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 lLDHx3+
显示结果: iIF'!K=q
type vender pcs mY
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电脑 A 1 ?#[K&$}
电脑 A 1 l2v}PALs
光盘 B 2 3AL.UBj&}
光盘 A 2 $I/p 6
手机 B 3 ueg X
手机 C 3 iB,*X[}EqG
23、说明:初始化表table1 U^YPL,m1
TRUNCATE TABLE table1 5 O6MI4:
24、说明:选择从10到15的记录 FD-)nv2:
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5;Z~+$1
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三、技巧 @t^2/H
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1、1=1,1=2的使用,在SQL语句组合时用的较多 <|_Ey)1
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, %51pf uL
如: >I!(CM":s$
if @strWhere !='' zc{C+:3$^
begin 2~4C5@SxL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere P>kx{^
end #RD%GLY
else ;'Q{ ywr
begin Rq9gtx8,=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Y5 opZG
end <@=NDUI3*,
我们可以直接写成 h
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #.='dSj
2、收缩数据库 gi6_la+
--重建索引 i,HAXPi
DBCC REINDEX ,@;<u'1\G
DBCC INDEXDEFRAG o MAK[$k;
--收缩数据和日志 =ht@7z8QM
DBCC SHRINKDB EAkP[au.
DBCC SHRINKFILE #n7{ 3)
3、压缩数据库 \[&]kPcDl
dbcc shrinkdatabase(dbname) ')aYkO{%sb
4、转移数据库给新用户以已存在用户权限 ?`XKaD!
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exec sp_change_users_login 'update_one','newname','oldname' DXGO-]!!0
go 9e5UTJ
5、检查备份集 PA/6l"-`3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b1OB'P8
6、修复数据库 r=`>'3
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ALTER DATABASE [dvbbs] SET SINGLE_USER 8B+uNN~%]
GO !v`=EF.
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cjW]Nw
GO -5[GX3h0
ALTER DATABASE [dvbbs] SET MULTI_USER ;$i'A&)OC
GO )/JC.d#
7、日志清除 HHYcFoJwYN
SET NOCOUNT ON Kv7NCpq'
DECLARE @LogicalFileName sysname, ivq4/Y]-X
@MaxMinutes INT, pDLo`F}A
@NewSize INT 0>`69&;g|
USE tablename -- 要操作的数据库名 smU+:~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 z)B=<4r
@MaxMinutes = 10, -- Limit on time allowed to wrap log. fm*Hk57
@NewSize = 1 -- 你想设定的日志文件的大小(M) 4HJrR^
-- Setup / initialize Qi61(lK
DECLARE @OriginalSize int S`G\Cd;5
SELECT @OriginalSize = size [ZbK)L+_
FROM sysfiles &)l:m.
WHERE name = @LogicalFileName i&$uG[&P
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #o RUH8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Sf8d|R@O
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' E(8g(?4
FROM sysfiles vn<S"
WHERE name = @LogicalFileName cjXwOk1:s
CREATE TABLE DummyTrans y
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(DummyColumn char (8000) not null) UQ)}i7v
DECLARE @Counter INT, hA8 zXk/'8
@StartTime DATETIME, !iw
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@TruncLog VARCHAR(255) -ZB"Yg$l
SELECT @StartTime = GETDATE(), EHZSM5hu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "Tv7*3>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ~-+Zu<
EXEC (@TruncLog) L DsYr]
-- Wrap the log if necessary. 8(}sZ)6
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *`#,^p`j
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) TRZ^$<AG
AND (@OriginalSize * 8 /1024) > @NewSize vF&b|V+,
BEGIN -- Outer loop. ]YP?bP,:
SELECT @Counter = 0 n1Jz49[r
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) '}u31V"SS
BEGIN -- update Pa}vmn1$
INSERT DummyTrans VALUES ('Fill Log') hbeC|_+
DELETE DummyTrans {/<&
SELECT @Counter = @Counter + 1 (=j!P*
END w^gh&E
EXEC (@TruncLog) pQNFH)=nw
END o__q)"^~-
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5qy}~dQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3o>t~Sfi
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^|C|=q~:
FROM sysfiles /Hmo!"W`
WHERE name = @LogicalFileName B]7jg9/
DROP TABLE DummyTrans Kxn7sL$]=F
SET NOCOUNT OFF N6;Z\\&0^q
8、说明:更改某个表 j,XKu5w)Oi
exec sp_changeobjectowner 'tablename','dbo' L|LTsRIq
9、存储更改全部表 arZIe+KW
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch <Xx\F56zp
@OldOwner as NVARCHAR(128), +0Gep}&z.
@NewOwner as NVARCHAR(128) Kcl$|T
AS #A;Z4jK
DECLARE @Name as NVARCHAR(128) AX+d? M
DECLARE @Owner as NVARCHAR(128) ''uI+>Y
DECLARE @OwnerName as NVARCHAR(128) p/h&_^EXU
DECLARE curObject CURSOR FOR UsN b&aue
select 'Name' = name, i1\2lh$
'Owner' = user_name(uid) BvF_9
from sysobjects rLxX^[Fp3
where user_name(uid)=@OldOwner _GqE'VX
order by name 1!3kAcBP
OPEN curObject ozLJ#eOE9
FETCH NEXT FROM curObject INTO @Name, @Owner fP58$pwu
WHILE(@@FETCH_STATUS=0) (, "E9.
BEGIN Gq/6{eRo\
if @Owner=@OldOwner k5D'RD
begin Tm52=+u f$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Q=E@i9c9
exec sp_changeobjectowner @OwnerName, @NewOwner s~
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end %%6('wi
-- select @name,@NewOwner,@OldOwner c'";36y
FETCH NEXT FROM curObject INTO @Name, @Owner dH|^\IQ
END &F_rg,q&_
close curObject x[UO1% _o-
deallocate curObject u9w&q^0dqG
GO Kdu\`c-lB
10、SQL SERVER中直接循环写入数据 8F`
declare @i int x-&v|w '
set @i=1 2p>SB/
while @i<30 Y)}%SP>,
begin Yj6p19
insert into test (userid) values(@i) "Q{~Bj~
set @i=@i+1 ,<b|@1\k
end _~Vz+nT
小记存储过程中经常用到的本周,本月,本年函数 ~uadivli
Dateadd(wk,datediff(wk,0,getdate()),-1) e"#D){k#
Dateadd(wk,datediff(wk,0,getdate()),6) 4Z9wzQ>
Dateadd(mm,datediff(mm,0,getdate()),0) ~+C?][T
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Y,btL'[W
Dateadd(yy,datediff(yy,0,getdate()),0) .A)Un/k7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) v&2@<I>
上面的SQL代码只是一个时间段 SzX~;pFM0
Dateadd(wk,datediff(wk,0,getdate()),-1) *`Xx _
Dateadd(wk,datediff(wk,0,getdate()),6) A(OfG&!
就是表示本周时间段. uz3pc;0LPY
下面的SQL的条件部分,就是查询时间段在本周范围内的: xY2_*#{.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) *)1Vs'!-
而在存储过程中 Wxau]uix
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [P=[hj;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) g)qnjeSs]