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。 <Q8d{--o
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一、基础 @=?#nB&
1、说明:创建数据库 >&JS-jFg
CREATE DATABASE database-name g6H` uO
2、说明:删除数据库 +;a\
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drop database dbname ${tBu#$-d
3、说明:备份sql server {A\y4D@
--- 创建 备份数据的 device L,3%}_
USE master -+Z&O?pSH
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h`D+NZtWm
--- 开始 备份 ([NS%
BACKUP DATABASE pubs TO testBack yW;]J87*
4、说明:创建新表 BAy)P1
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }O:l]O`
根据已有的表创建新表: Z#@<|{eI
A:create table tab_new like tab_old (使用旧表创建新表) |iVw7M:
B:create table tab_new as select col1,col2... from tab_old definition only mpzm6Ieu
5、说明:删除新表 V7?Pv
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drop table tabname 4EJ6Zy![0*
6、说明:增加一个列 ~Dj_N$_+9
Alter table tabname add column col type w_#5Na}>d
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 3Ol`i$
7、说明:添加主键: Alter table tabname add primary key(col) t7/a5x
说明:删除主键: Alter table tabname drop primary key(col) m</nOf+C
8、说明:创建索引:create [unique] index idxname on tabname(col....) @|}=W Q
删除索引:drop index idxname #rx@
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注:索引是不可更改的,想更改必须删除重新建。 ZRYHsl{F+
9、说明:创建视图:create view viewname as select statement ETaLE[T%1
删除视图:drop view viewname <a=k"'0
10、说明:几个简单的基本的sql语句 .*L_*}tno
选择:select * from table1 where 范围 !qJ|`o Y
插入:insert into table1(field1,field2) values(value1,value2) r%II`
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删除:delete from table1 where 范围 BoXGoFn
更新:update table1 set field1=value1 where 范围 vH vwH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D?P1\<A~
排序:select * from table1 order by field1,field2 [desc] WQ1*)h8,9
总数:select count as totalcount from table1 6E.64+PJw
求和:select sum(field1) as sumvalue from table1 !Baq4V?KN
平均:select avg(field1) as avgvalue from table1 _"sFLe{
最大:select max(field1) as maxvalue from table1 /N`E4bKBR
最小:select min(field1) as minvalue from table1 +7bV
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11、说明:几个高级查询运算词 u9) <i]2
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A: UNION 运算符 FrD,)Ad8Q
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。 xZ(VvINL'
B: EXCEPT 运算符 X&({`Uw<K
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。 D[R<H((
C: INTERSECT 运算符 (Y?"L_pC
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。 R(F+Xgje
注:使用运算词的几个查询结果行必须是一致的。 OcGHMGdn
12、说明:使用外连接 kDr0D$iE
A、left outer join: GHo=)NTjy
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。 :1\QM'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 }mSfg
B:right outer join: olO&7jh7|
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。 m8njP-CZ
C:full outer join: 3ws}E6\D
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。 bol#[_~
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二、提升 OA3* "d*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) CGkCLd*s]
法一:select * into b from a where 1<>1 A1(=7ZKz
法二:select top 0 * into b from a eb>YvC
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ce\ F~8y
insert into b(a, b, c) select d,e,f from b; FUj4y 9X
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) yp:_W@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 A9HJWKO
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -w:F8k ~
4、说明:子查询(表名1:a 表名2:b) 'Nbae-pf
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) S<V__Sv
5、说明:显示文章、提交人和最后回复时间 aj<=]=hr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b p x1{=~V/
6、说明:外连接查询(表名1:a 表名2:b) r*!sA5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }{Ncww!iN
7、说明:在线视图查询(表名1:a ) Q}MS $[y
select * from (SELECT a,b,c FROM a) T where t.a > 1; RjS&^uaP
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
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select * from table1 where time between time1 and time2 @i[z4)"S
select a,b,c, from table1 where a not between 数值1 and 数值2 d8? }69:h
9、说明:in 的使用方法 $6XCHVx
select * from table1 where a [not] in ('值1','值2','值4','值6') t3)nG8>
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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 "38ya2*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Y(4#b`k3
11、说明:四表联查问题: XHu2G t_
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 ..... + fQ=G/
12、说明:日程安排提前五分钟提醒 G,8LF/sR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^rc!X]C9
13、说明:一条sql 语句搞定数据库分页 :>.~"uWo{
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 8h#/b1\
14、说明:前10条记录 >~5>)yN_a1
select top 10 * form table1 where 范围 j6~#_t[
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.) Ny>tJ~I
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5CxD ys&<
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 >y&4gm
(select a from tableA ) except (select a from tableB) except (select a from tableC) P{eL;^I
17、说明:随机取出10条数据 wyk4v}
select top 10 * from tablename order by newid() Z%Nl<i
18、说明:随机选择记录 -O2ZrJ!q
select newid() 05\A7.iy
19、说明:删除重复记录 )j40hrR
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 aZYa<28?L%
select name from sysobjects where type='U' RpE69:~PV
21、说明:列出表里的所有的 i!jZZj-{
select name from syscolumns where id=object_id('TableName') Ch`XwLY9
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。 J 3fcnI
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 zA&lJD$0
显示结果: 5uK:f\y)l
type vender pcs )z9)oM\
电脑 A 1 f~u]fpkz
电脑 A 1 +k'5W1e
光盘 B 2 H'E>QT
光盘 A 2 [ds:LQq)/
手机 B 3 #;Y JR9VN
手机 C 3 Da!A1|"
23、说明:初始化表table1 VpJ/M(UD-
TRUNCATE TABLE table1 *r)/.rK_
24、说明:选择从10到15的记录 h#?L6<*tm
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc bE2^sx`(
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三、技巧 KvC`6
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^zHBDRsb2F
"where 1=1" 是表示选择全部 "where 1=2"全部不选, NaSg K
如: &AmTXW
if @strWhere !='' ^c}Z$V
begin ^ad
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere FFl[[(`%D
end pGz-5afL
else _*1/4^
begin QF(.fq8, U
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >v @R]9
end ua*k{0[
我们可以直接写成 m]BxGwT=m
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KFdTw{GlJ7
2、收缩数据库 ^SB?NRk
--重建索引 mc;Z#"kf
DBCC REINDEX zR(}X8fP
DBCC INDEXDEFRAG @.T
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--收缩数据和日志 jpZ, $
DBCC SHRINKDB ~`c?&YixU
DBCC SHRINKFILE $*^Ms>Pa_
3、压缩数据库 WF<`CQ g[
dbcc shrinkdatabase(dbname) 3>%rm%ffE
4、转移数据库给新用户以已存在用户权限 zME75;{
exec sp_change_users_login 'update_one','newname','oldname' .`&($W
go )f9f_^;
5、检查备份集 G=!1P]M{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Z 9mY*}:U~
6、修复数据库 xz5 Jli
ALTER DATABASE [dvbbs] SET SINGLE_USER _Iy0-=G
GO
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO a:Jsi=
ALTER DATABASE [dvbbs] SET MULTI_USER W"+*%x
GO Mib(J+Il
7、日志清除 [!p>Id
SET NOCOUNT ON ~~k_A|&
DECLARE @LogicalFileName sysname, An!1>`8r
@MaxMinutes INT, Ehu^_HZ
@NewSize INT }z1aKa9
USE tablename -- 要操作的数据库名 -hw^3Af
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !`L%wS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]#;;)K}>
@NewSize = 1 -- 你想设定的日志文件的大小(M) =.O8G=;DOA
-- Setup / initialize g-"@%ps
DECLARE @OriginalSize int Yo3my>N&g
SELECT @OriginalSize = size {/G~HoY1i
FROM sysfiles ;75K:_
WHERE name = @LogicalFileName 1=gE,k5H
SELECT 'Original Size of ' + db_name() + ' LOG is ' + iTF`sjL
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + u8L%R[#o
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' hdt;_qa
FROM sysfiles NpqMdd
WHERE name = @LogicalFileName \,)('tUE
CREATE TABLE DummyTrans F7lhLly
(DummyColumn char (8000) not null) Ya{$:90(4
DECLARE @Counter INT, ste0:.*qb
@StartTime DATETIME, O4J <u-E$
@TruncLog VARCHAR(255) ^N#B(F
SELECT @StartTime = GETDATE(), "1|n]0BF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' N|-M|1w96
DBCC SHRINKFILE (@LogicalFileName, @NewSize) AL@8v=
EXEC (@TruncLog) K8M[xaI@
-- Wrap the log if necessary. <y[LdB/a
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired a (RTb<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) N\{Xhr7d
AND (@OriginalSize * 8 /1024) > @NewSize .Qk T-12
BEGIN -- Outer loop. y "6;O 0
SELECT @Counter = 0 ;Gixu9u'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) t4(Z@X$
BEGIN -- update 6BK-(>c(6
INSERT DummyTrans VALUES ('Fill Log') `&y Qtj#
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DELETE DummyTrans [w*YH5kX
SELECT @Counter = @Counter + 1 vpnQ s#8O
END T40&a(hXQ
EXEC (@TruncLog) ZLm?8g6-
END QS(aA*D
SELECT 'Final Size of ' + db_name() + ' LOG is ' + VRden>vKN
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + d [K71
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,5}%_
FROM sysfiles *-Y`7=^$
WHERE name = @LogicalFileName Wk<he F
DROP TABLE DummyTrans G*;?&;*
SET NOCOUNT OFF t<=Ru*p
8、说明:更改某个表 4z6i{n-k
exec sp_changeobjectowner 'tablename','dbo' ; '6`hZ
9、存储更改全部表 VPOzt7:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch K9-;-{qb
@OldOwner as NVARCHAR(128), T($d3Nn1
@NewOwner as NVARCHAR(128) >Sc)?[H
AS rdj_3Utv
DECLARE @Name as NVARCHAR(128) M9[52D!{
DECLARE @Owner as NVARCHAR(128) G-7!|&
DECLARE @OwnerName as NVARCHAR(128) arVu`pD*n
DECLARE curObject CURSOR FOR Oly"ll*K
select 'Name' = name, Nk
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'Owner' = user_name(uid) FR*CiaD1
from sysobjects
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where user_name(uid)=@OldOwner RBOb/.$
order by name ,s ` y
OPEN curObject B'NtG84
FETCH NEXT FROM curObject INTO @Name, @Owner 4Fu:ov
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WHILE(@@FETCH_STATUS=0) "Yp:{e
BEGIN qStZW^lFeY
if @Owner=@OldOwner %_P[
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begin 5r2A^<)
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [|qV*3|?
exec sp_changeobjectowner @OwnerName, @NewOwner 8Cx6Me>,=
end =Ff _)k
-- select @name,@NewOwner,@OldOwner d9=i{i3
FETCH NEXT FROM curObject INTO @Name, @Owner KUD.hK.
END fk*I}pDx
close curObject og[cwa_
deallocate curObject eW<|I
GO @GVONluyU`
10、SQL SERVER中直接循环写入数据 #Vy8<Vy&w
declare @i int \k4em{K
set @i=1 A4~-{.w=
while @i<30 Vb @lK~
begin olv0w;s
insert into test (userid) values(@i) | V:9 ][\
set @i=@i+1 G'U ! #
end ikd1KF+I
小记存储过程中经常用到的本周,本月,本年函数 ""f'L,`{.
Dateadd(wk,datediff(wk,0,getdate()),-1) IRknD3LX
Dateadd(wk,datediff(wk,0,getdate()),6) eS: 8Pn
Dateadd(mm,datediff(mm,0,getdate()),0) 9 _oAs"w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) H:#sf][&,L
Dateadd(yy,datediff(yy,0,getdate()),0) XN^l*Q?3n
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) c4f3Dr'xw
上面的SQL代码只是一个时间段 eF"k"Ckt'
Dateadd(wk,datediff(wk,0,getdate()),-1) eKUP,y;[I
Dateadd(wk,datediff(wk,0,getdate()),6) NNxzZ!q!
就是表示本周时间段. ]*Cq'<h$
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^`S.Mw.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) XfQK
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而在存储过程中 ID]E3K
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p:NIRs
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ["_+~*