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。 kuMKX`_
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一、基础 )}lRd#V
1、说明:创建数据库 ^))RM_ic
CREATE DATABASE database-name p<GR SJIk=
2、说明:删除数据库 !PUZWO
drop database dbname X&\d)/Y
3、说明:备份sql server kI\tqNJ i
--- 创建 备份数据的 device J./d!an
USE master ~}9PuYaD@
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #2p#VQh
--- 开始 备份 lFG9=Wf
BACKUP DATABASE pubs TO testBack [ AzO:A
4、说明:创建新表 > 0>
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]ya; v '
根据已有的表创建新表: RrV>r<Z"Q
A:create table tab_new like tab_old (使用旧表创建新表) 'S4)?Z
B:create table tab_new as select col1,col2... from tab_old definition only e{w>%)rcP
5、说明:删除新表 :QQlI
drop table tabname k3Cz9Vt%
6、说明:增加一个列 i775:j~zx0
Alter table tabname add column col type @R6 ttx
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。 ,J=P,](
7、说明:添加主键: Alter table tabname add primary key(col) hwnJE958L
说明:删除主键: Alter table tabname drop primary key(col) YlK7;yrq(
8、说明:创建索引:create [unique] index idxname on tabname(col....) p3951-D
删除索引:drop index idxname FiAY\4
注:索引是不可更改的,想更改必须删除重新建。 n> w`26MMp
9、说明:创建视图:create view viewname as select statement Sb&lhgW]c
删除视图:drop view viewname )]6hy9<
10、说明:几个简单的基本的sql语句 ).412I
选择:select * from table1 where 范围 :py\|
插入:insert into table1(field1,field2) values(value1,value2) P Ru&3BP
删除:delete from table1 where 范围 2b@tj
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更新:update table1 set field1=value1 where 范围 z}4L=KR\v
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ,_v|#g@{
排序:select * from table1 order by field1,field2 [desc] n.6T
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总数:select count as totalcount from table1 `FF8ie 8L
求和:select sum(field1) as sumvalue from table1 D)b}f`
平均:select avg(field1) as avgvalue from table1 s'HD{W`
最大:select max(field1) as maxvalue from table1 _r Y,}\
最小:select min(field1) as minvalue from table1 ;@mRo`D`
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11、说明:几个高级查询运算词 \}*k)$r
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A: UNION 运算符 $hrIO+
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 cWAtju?L;
B: EXCEPT 运算符 {=:#S+^ER
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 )q~DTR^z-
C: INTERSECT 运算符 C}}/)BYi
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 k%'m *T f
注:使用运算词的几个查询结果行必须是一致的。 3\$wdUFr
12、说明:使用外连接 GC@+V|u
A、left outer join: =6 r:A<F!n
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 7N8H)X
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c J1ON,&[J
B:right outer join: BzJ;%ywS
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 A&5:ATQ/|
C:full outer join: .)XP\m\
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 @I3eK^#|P
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二、提升 n`7f"'/:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) P A;6$vqX
法一:select * into b from a where 1<>1 {d3<W N
法二:select top 0 * into b from a vXj <
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Q+q,!w8
insert into b(a, b, c) select d,e,f from b; 63WS7s"
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) L,[;k
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 TbVn6V'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. < B g8,;
4、说明:子查询(表名1:a 表名2:b) /*)Tl
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) %D}H|*IPu
5、说明:显示文章、提交人和最后回复时间 =^DLywAh}u
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b G'z{b$?/[
6、说明:外连接查询(表名1:a 表名2:b) =<z.mzqu5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {r85l\u)Q\
7、说明:在线视图查询(表名1:a ) TX8<J>x
select * from (SELECT a,b,c FROM a) T where t.a > 1; cQj-+Tmu
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 +/{L#e>
select * from table1 where time between time1 and time2 H1:be.^YP
select a,b,c, from table1 where a not between 数值1 and 数值2 wNJzwC&iQ
9、说明:in 的使用方法 Vy<HA*
select * from table1 where a [not] in ('值1','值2','值4','值6') xG2F!WeF
10、说明:两张关联表,删除主表中已经在副表中没有的信息 '_P\#7$!MV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,zTb<g
11、说明:四表联查问题: XL}"1lE
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 ..... *>8ce-PV
12、说明:日程安排提前五分钟提醒 ZAKeEm2A
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "`Ge~N[$A
13、说明:一条sql 语句搞定数据库分页 e 8\;t"D
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 :nY2O
14、说明:前10条记录 .4y>QN#VL
select top 10 * form table1 where 范围 4-GXmC
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) bru/AZ# de
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (oz$B0HO:
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 lK7m=[j
(select a from tableA ) except (select a from tableB) except (select a from tableC) ow'Vz
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17、说明:随机取出10条数据 Mj=$y?d ]
select top 10 * from tablename order by newid() ./6<r OW
18、说明:随机选择记录 :aLT0q!K
select newid() AV8T
19、说明:删除重复记录 |Hr:S":9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) po9
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20、说明:列出数据库里所有的表名 Z)9g~g94
select name from sysobjects where type='U' {XurC}#\
21、说明:列出表里的所有的 BP[|nL
select name from syscolumns where id=object_id('TableName') ^ZDBO/
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。 n.oUVr=nX
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 @F*wg
显示结果: fl\aqtF
type vender pcs J8a*s`ik
电脑 A 1 'J)2g"T@
电脑 A 1 `Mj}md;O"
光盘 B 2 -f1k0QwL
光盘 A 2 ![6EUMx
手机 B 3 q=Zr>I;(Ks
手机 C 3 +k<w!B*
23、说明:初始化表table1 x`RTp:#
TRUNCATE TABLE table1 >O9o,o/6R
24、说明:选择从10到15的记录 d5 Edu44
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lK'Rn~
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三、技巧 zhI#f0c
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, YV4#%I!<
如: (6p]ZY
if @strWhere !='' #zUXyT#X
begin "[p@tc?5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =QJRMF
end DaH Z{T8>d
else Pl=] Srw
begin c?2MBtnu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' J<gJc*Q
end h&3YGCl
我们可以直接写成 ZSy?T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9Mp$8-=>7
2、收缩数据库 %#L]]-%
--重建索引 2?C`4AR[2H
DBCC REINDEX 3VnQnd E
DBCC INDEXDEFRAG |%a4`w
--收缩数据和日志 ,6^znOt
DBCC SHRINKDB C`jM0Q
DBCC SHRINKFILE ;^Sr"v6r>u
3、压缩数据库 w@\vHH.;V
dbcc shrinkdatabase(dbname) (UCK;k
4、转移数据库给新用户以已存在用户权限 Qcjc,
exec sp_change_users_login 'update_one','newname','oldname' x3ERCqTR
go 5l-mW0,MK
5、检查备份集 8N%Bn&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' _/* U2.xS
6、修复数据库 ^>y@4q B
ALTER DATABASE [dvbbs] SET SINGLE_USER ]'~vI/p
GO c)md
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $/1c= Y@
GO f&,{XZ
ALTER DATABASE [dvbbs] SET MULTI_USER 60=m
GO OX:O^ (-r,
7、日志清除 qH,l#I\CG
SET NOCOUNT ON R=Ws#'
DECLARE @LogicalFileName sysname, Nr<`Z
@MaxMinutes INT, @.$Xv>Jt$
@NewSize INT +y2[msBs
USE tablename -- 要操作的数据库名 }{ 9&:!uA
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^04Q %,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. U!%!m'
@NewSize = 1 -- 你想设定的日志文件的大小(M) 5Ky#GuC
-- Setup / initialize 2O"P2(1}v
DECLARE @OriginalSize int l%z< (L5
SELECT @OriginalSize = size *Oc.9 F88"
FROM sysfiles Awv`) "RAR
WHERE name = @LogicalFileName XMB[h
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;;$# )b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + C${S^v
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ajRSMcKb7i
FROM sysfiles p Rdk>Ph
WHERE name = @LogicalFileName 7?gFy-
CREATE TABLE DummyTrans 3cS2gxF
(DummyColumn char (8000) not null) {j {+0V
DECLARE @Counter INT, Rd7_~.Bo
@StartTime DATETIME, d%I"/8-J
@TruncLog VARCHAR(255) C9DJO:f.2y
SELECT @StartTime = GETDATE(), H2xeP%;$
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' o`zr>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) :!;'J/B@..
EXEC (@TruncLog) . #Z+Z
-- Wrap the log if necessary. R:JX<Ba
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Ll4bdz,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) $P7iRM]
AND (@OriginalSize * 8 /1024) > @NewSize j6~nE'sQ
BEGIN -- Outer loop. X7UuwIIP
SELECT @Counter = 0 ;g_>
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) G!8Z~CPF
BEGIN -- update v1k)hFjPK
INSERT DummyTrans VALUES ('Fill Log') 5m=I*.qE
DELETE DummyTrans MC((M,3L
SELECT @Counter = @Counter + 1 '/Bidb?
END UmnE@H"t$\
EXEC (@TruncLog) e6X[vc|Y}
END -"Y{$/B
SELECT 'Final Size of ' + db_name() + ' LOG is ' + D9mz9
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2-zT$`[]J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' V]c;^
FROM sysfiles KD1=Y80P
WHERE name = @LogicalFileName =ItkFjhBc
DROP TABLE DummyTrans z)XRx:YU;$
SET NOCOUNT OFF b5IA"w
8、说明:更改某个表 =&0wr6
exec sp_changeobjectowner 'tablename','dbo' Bx"7%[
9、存储更改全部表 t#nn@Yf
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]nQt>R p_
@OldOwner as NVARCHAR(128), r!P}u
@NewOwner as NVARCHAR(128) 2>-S-;i
AS
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DECLARE @Name as NVARCHAR(128) RO0>I8c1c
DECLARE @Owner as NVARCHAR(128) 3Y)PU=
DECLARE @OwnerName as NVARCHAR(128) {Y}dv`G#Iu
DECLARE curObject CURSOR FOR aw?=hXR!
select 'Name' = name, =z{JgD/
'Owner' = user_name(uid) +5.t. d
from sysobjects ri C[lB
where user_name(uid)=@OldOwner N4;7gSc"
order by name !/ y!QXj
OPEN curObject @`-[;?>
FETCH NEXT FROM curObject INTO @Name, @Owner 6OiSK@<Hk
WHILE(@@FETCH_STATUS=0) [U#72+K
BEGIN T&T/C@z'R
if @Owner=@OldOwner
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begin &bgvy'p
set @OwnerName = @OldOwner + '.' + rtrim(@Name) P^MOx4
exec sp_changeobjectowner @OwnerName, @NewOwner G5dO 3lwq
end q(5j(G ;
-- select @name,@NewOwner,@OldOwner
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FETCH NEXT FROM curObject INTO @Name, @Owner b,P ]9$Ut
END ~`>e5OgOJ
close curObject /2{5;
deallocate curObject .yT8NTu~0j
GO mD:IO
10、SQL SERVER中直接循环写入数据 FtufuL?JS
declare @i int a"/#+=[
set @i=1 Y=Z1Tdxa|
while @i<30 'tN25$=V&W
begin iDl;!b&V.
insert into test (userid) values(@i)
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set @i=@i+1 Vh3Ijn
end &Gm$:T'~
小记存储过程中经常用到的本周,本月,本年函数 +,:^5{9{
Dateadd(wk,datediff(wk,0,getdate()),-1) Rj~
Dateadd(wk,datediff(wk,0,getdate()),6) TUT][
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Dateadd(mm,datediff(mm,0,getdate()),0) =O _z(
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) d1!i(MaV!
Dateadd(yy,datediff(yy,0,getdate()),0) DlMe5=n-u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #X:
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上面的SQL代码只是一个时间段 D3Jr3
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Dateadd(wk,datediff(wk,0,getdate()),-1) 53HU.
Dateadd(wk,datediff(wk,0,getdate()),6) =k3!RW'
就是表示本周时间段. %2'A
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下面的SQL的条件部分,就是查询时间段在本周范围内的: S1n3(U:m
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) j4FeSGa
而在存储过程中 Lf:uNl*D
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ` b !5^W
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) O 2{)WWOT