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。 <z+:j!~
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一、基础 yGBQ0o7E
1、说明:创建数据库 I`RBj `IF
CREATE DATABASE database-name @~
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2、说明:删除数据库 le)DgIT>=
drop database dbname :t$aN|>y
3、说明:备份sql server NLd``=&
--- 创建 备份数据的 device 8;P2A\X
USE master 8^^[XbH
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' j`*N,*ha
--- 开始 备份 4R%*Z~
BACKUP DATABASE pubs TO testBack E|EgB33S
4、说明:创建新表 ~,6b_W p/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 4DWwbO
根据已有的表创建新表: R0Ue0pF7
A:create table tab_new like tab_old (使用旧表创建新表) mABe'"8
B:create table tab_new as select col1,col2... from tab_old definition only \uOdALZ
5、说明:删除新表 5~
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drop table tabname :\~+#/=:
6、说明:增加一个列 %GEJnJ
Alter table tabname add column col type hjx)D
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Yd
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7、说明:添加主键: Alter table tabname add primary key(col) |aToUi.Q%
说明:删除主键: Alter table tabname drop primary key(col) >-<8N-@"n
8、说明:创建索引:create [unique] index idxname on tabname(col....) O;Y:uHf
删除索引:drop index idxname neF]=uCWnT
注:索引是不可更改的,想更改必须删除重新建。 ,3DXFV'uxb
9、说明:创建视图:create view viewname as select statement ov#7hxe
删除视图:drop view viewname &:B<Q$g#
10、说明:几个简单的基本的sql语句 :VmHfOO
选择:select * from table1 where 范围 KGHq rc
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 7sNw
更新:update table1 set field1=value1 where 范围 1r)kR@!LNG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! H(^bC5'
排序:select * from table1 order by field1,field2 [desc] n";02?@F
总数:select count as totalcount from table1 u0`o A
求和:select sum(field1) as sumvalue from table1 `'_m\uo
平均:select avg(field1) as avgvalue from table1 DrW#v-d
最大:select max(field1) as maxvalue from table1 ^,Ydr~|T
最小:select min(field1) as minvalue from table1 #b0{#^S:
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11、说明:几个高级查询运算词 0x!2ihf
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A: UNION 运算符 h;0S%ZC
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。 ,GgAsj: K
B: EXCEPT 运算符 M
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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。 @/1w4'M
C: INTERSECT 运算符 3g6j?yYqb
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。 =lpQnj"
注:使用运算词的几个查询结果行必须是一致的。 J4\ qEO
12、说明:使用外连接 Q1z;/A$Al
A、left outer join: iya"ky~H
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 }C|dyyr
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c &
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B:right outer join: %D[0nt|X
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 =J~ x
C:full outer join: Rx+p.
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 )[Yv?>ib
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二、提升 b2FO$Os
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Ft!],n-n*
法一:select * into b from a where 1<>1 NG6& :4!
法二:select top 0 * into b from a SZXY/~=h
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) M^]cM(swK5
insert into b(a, b, c) select d,e,f from b; l(#)WWr+
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) =3v]gOcO
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 _hk.2FV:3m
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @i*|s~15
4、说明:子查询(表名1:a 表名2:b) %x}
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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) FeTL&$O
5、说明:显示文章、提交人和最后回复时间 ::/j$bL
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _:VB}>
6、说明:外连接查询(表名1:a 表名2:b) YGsWu7dG
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @W9x$
7、说明:在线视图查询(表名1:a ) GbaEgA'fa
select * from (SELECT a,b,c FROM a) T where t.a > 1; icgSe:Ci
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 g"> {9YE
select * from table1 where time between time1 and time2 PKzyV ;
select a,b,c, from table1 where a not between 数值1 and 数值2 :]1TGfS
9、说明:in 的使用方法 v@d
select * from table1 where a [not] in ('值1','值2','值4','值6') r#Oo
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?%y?rk <
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +o51x'Ld*
11、说明:四表联查问题: yYH 0v7vx+
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 ..... =pC3~-;3
12、说明:日程安排提前五分钟提醒 yT,.z 0
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ..R-Ms)k=
13、说明:一条sql 语句搞定数据库分页 r'*}TM'8
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 x3"#POp
14、说明:前10条记录 oGRhnP'PF+
select top 10 * form table1 where 范围 S9",d~EM
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.) ;{%\9nS
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) L~NbdaO
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 \<)9?M :
(select a from tableA ) except (select a from tableB) except (select a from tableC) UZpIcj cL
17、说明:随机取出10条数据 r|qp3x
select top 10 * from tablename order by newid() gE?|_x#
18、说明:随机选择记录 \9g+^vQg
select newid() ;hjwD
19、说明:删除重复记录 GJqJlgHe
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) LmnymcH
20、说明:列出数据库里所有的表名 <"r#:Wr
select name from sysobjects where type='U' E L9]QI
21、说明:列出表里的所有的 /Dj=iBO
select name from syscolumns where id=object_id('TableName') &mtJRfnu
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。 6gs01c,BA
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 KW^7H
显示结果: vCwe'q`1
type vender pcs b8LLr;oQw
电脑 A 1 j_.5r&w
电脑 A 1 SV~~Q_U9
光盘 B 2 A'&K/) Z
光盘 A 2 /
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手机 B 3 ^kB8F"X
手机 C 3 Ls] g
23、说明:初始化表table1 T
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TRUNCATE TABLE table1 LB a[:j2
24、说明:选择从10到15的记录 c:o]d )S
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc hj.a&%
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三、技巧 U5.LDv;
1、1=1,1=2的使用,在SQL语句组合时用的较多 ;k>&FWEG
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 2
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如: qtQ6cqLd
if @strWhere !='' VYk!k3qS
begin Dw<bn<e-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .jk@IL
end =aBctd:eX`
else ~U@;gLoD
begin mSb#Nn6W
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Pn>Xbe
end HTS%^<u
我们可以直接写成 B=^)Ub5'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m;GbLncA
2、收缩数据库 ? -dX`n
--重建索引 +
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DBCC REINDEX lY?QQ01D
DBCC INDEXDEFRAG K|hjEQRv
--收缩数据和日志 UVd 7 JGR
DBCC SHRINKDB O\"3J(y,
DBCC SHRINKFILE 5',8 ziJQ
3、压缩数据库 1Y7Eajt-5
dbcc shrinkdatabase(dbname) {^7Hgg
4、转移数据库给新用户以已存在用户权限 &)AVzN+*h
exec sp_change_users_login 'update_one','newname','oldname' eOs)_?}
go YSTv\y
5、检查备份集 O06"bi5Y
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $JMXV
6、修复数据库 hp 5|@
ALTER DATABASE [dvbbs] SET SINGLE_USER sP;nGQ.eN
GO 10q'Z}34
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &h^9}>rVjV
GO ]v]qChZHd
ALTER DATABASE [dvbbs] SET MULTI_USER Of[XKFn_
GO O$&mFL[`
7、日志清除 ;h*K }U
SET NOCOUNT ON =WyZX 7@R
DECLARE @LogicalFileName sysname, -xEXN[\S
@MaxMinutes INT, P(,p'I;j
@NewSize INT di6QVRj1
USE tablename -- 要操作的数据库名 zxbpEJzpn
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 j}JrE,|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =}DR)
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@NewSize = 1 -- 你想设定的日志文件的大小(M) p~BRh
-- Setup / initialize CohDO
DECLARE @OriginalSize int ifUGY[ L
SELECT @OriginalSize = size ^Eb.:}!D6
FROM sysfiles Y&d00
WHERE name = @LogicalFileName Sjyoc<Uo
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 'B 43_
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Vzdh8)Mu\
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $Q96,rb}k;
FROM sysfiles beRVD>T
WHERE name = @LogicalFileName /H(?
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CREATE TABLE DummyTrans si`A:14R
(DummyColumn char (8000) not null) j.w@(<=x
DECLARE @Counter INT,
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@StartTime DATETIME, _wkVwPr
@TruncLog VARCHAR(255) s:#V(<J
SELECT @StartTime = GETDATE(), 4cabP}gBk
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &,c``z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ^;Y|3)vvB
EXEC (@TruncLog) r@+ri1c
-- Wrap the log if necessary. G-xDN59K
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #sPHdz'3M
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) VY;{/.Sa
AND (@OriginalSize * 8 /1024) > @NewSize 6y+Kjd/D
BEGIN -- Outer loop. <lw`
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SELECT @Counter = 0 (@<lRA
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -:2$ %
BEGIN -- update ko.(pb@+
INSERT DummyTrans VALUES ('Fill Log') hxVKV?Fl
DELETE DummyTrans ;aI[=?<x
SELECT @Counter = @Counter + 1 vy0X_DPCr
END ;A|-n1e>Hc
EXEC (@TruncLog) }4Tc
END ;3d"wW]}7K
SELECT 'Final Size of ' + db_name() + ' LOG is ' + /tP|b_7O
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |zQ4u
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' fBRo_CU8!
FROM sysfiles !k63`(Ti
WHERE name = @LogicalFileName O"Q=66.CR
DROP TABLE DummyTrans RP9||PFS~~
SET NOCOUNT OFF F/Xhm91^
8、说明:更改某个表 vI@8DWs
exec sp_changeobjectowner 'tablename','dbo' I1,?qr"Zr
9、存储更改全部表 8ZDq
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ghl9gFFj
@OldOwner as NVARCHAR(128), K0]Wb=v
@NewOwner as NVARCHAR(128) nj[6c
AS AXCJFqk;
DECLARE @Name as NVARCHAR(128) gNeCnf#Xa
DECLARE @Owner as NVARCHAR(128) gnGw7V
DECLARE @OwnerName as NVARCHAR(128) a4yU[KK
DECLARE curObject CURSOR FOR ,J~dER\%
select 'Name' = name, ?0x;L/d])
'Owner' = user_name(uid) YAog;QL
from sysobjects uRIr,U^
where user_name(uid)=@OldOwner ;b^@o,=
order by name h|
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OPEN curObject R/W&~t
FETCH NEXT FROM curObject INTO @Name, @Owner H;6V
WHILE(@@FETCH_STATUS=0) `
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BEGIN y[cAU:P?
if @Owner=@OldOwner ;k0*@c*
begin fCKcv |
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ]:;gk&P
exec sp_changeobjectowner @OwnerName, @NewOwner gS%J`X$
end ,<BTv;4p
-- select @name,@NewOwner,@OldOwner H4N==o
FETCH NEXT FROM curObject INTO @Name, @Owner ~BC5no
END ]q j%6tz
close curObject eXYR/j<8
deallocate curObject p82qFzq#
GO
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10、SQL SERVER中直接循环写入数据 ,oCr6 ]
declare @i int =k'dbcfO$9
set @i=1 7Q`4*H6
while @i<30 [;(|^0
begin bke 1 F
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insert into test (userid) values(@i) >QyMeH
set @i=@i+1 0V^?~ex
end Pw")|85
小记存储过程中经常用到的本周,本月,本年函数 r~sGot+sQA
Dateadd(wk,datediff(wk,0,getdate()),-1) ,FTF@h-Cs
Dateadd(wk,datediff(wk,0,getdate()),6) Na=q(OKN
Dateadd(mm,datediff(mm,0,getdate()),0) _]\mh,}
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 'D1@+FFU0
Dateadd(yy,datediff(yy,0,getdate()),0) GXAcyOV
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0zd1:*KR,
上面的SQL代码只是一个时间段 hi37p1t
Dateadd(wk,datediff(wk,0,getdate()),-1) w4OVfTlN
Dateadd(wk,datediff(wk,0,getdate()),6) n8?gZ` W
就是表示本周时间段. qRU8uu
下面的SQL的条件部分,就是查询时间段在本周范围内的: a^2?W
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6} 9A0
而在存储过程中 xzy9~))o
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) i_MDLS>-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]`MRH[{