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。 ~e ]83?
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一、基础 ggJn oL
1、说明:创建数据库 +<|6y46
CREATE DATABASE database-name hqD]^P>l1
2、说明:删除数据库 C{-e(G`Yd
drop database dbname B Lw ssr.
3、说明:备份sql server [[Qu|?KEa
--- 创建 备份数据的 device =d.Z:L9d
USE master F^3Q0KsT
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' V
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--- 开始 备份 >q[ (UV
BACKUP DATABASE pubs TO testBack 3iR;(l}
4、说明:创建新表 \;.\g6zX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +P6q
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根据已有的表创建新表: yWsNG;>
A:create table tab_new like tab_old (使用旧表创建新表) @iS(P u
B:create table tab_new as select col1,col2... from tab_old definition only ~*- eL.
5、说明:删除新表 E
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drop table tabname |.)oV;9
6、说明:增加一个列 arrNx|y
Alter table tabname add column col type JN$v=Ox{
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 +0;6.PK
7、说明:添加主键: Alter table tabname add primary key(col) U<KvKg
说明:删除主键: Alter table tabname drop primary key(col) [- a2<E
8、说明:创建索引:create [unique] index idxname on tabname(col....) %'%ej^s-R
删除索引:drop index idxname b Zn:q[7
注:索引是不可更改的,想更改必须删除重新建。 7^ITedW@
9、说明:创建视图:create view viewname as select statement >|/NDF=\s
删除视图:drop view viewname 7Xw;TA
10、说明:几个简单的基本的sql语句 !G90oW
选择:select * from table1 where 范围 `QnKal )
插入:insert into table1(field1,field2) values(value1,value2) )d2 <;c
删除:delete from table1 where 范围 _K_!(]t
更新:update table1 set field1=value1 where 范围 QDF1$,s4i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! (UAa
排序:select * from table1 order by field1,field2 [desc] i"r&CS)sT
总数:select count as totalcount from table1 cX>
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求和:select sum(field1) as sumvalue from table1 vjhd|
平均:select avg(field1) as avgvalue from table1 0V1)ou84'
最大:select max(field1) as maxvalue from table1 }'b3'/MJ
最小:select min(field1) as minvalue from table1 _b&Mrd
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11、说明:几个高级查询运算词 h*Rh:yCR>
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A: UNION 运算符 qb]n{b2
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。 _rR+u56y-
B: EXCEPT 运算符 p&>*bF,
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}>pl8ke~g
C: INTERSECT 运算符 q?nXhUD
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。 \j+O |#`|)
注:使用运算词的几个查询结果行必须是一致的。 %FDi7Rx
12、说明:使用外连接 +%OINMo.A
A、left outer join: O={4 >>F
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。 k?;A#L~
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 JN .\{ Y
B:right outer join: /!=uM.
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。 TUw^KSa
C:full outer join: u}\F9~W-{
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。 }/nbv;)
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二、提升 w4Qqo(
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) j&6,%s-M`a
法一:select * into b from a where 1<>1 GvF8S MO[x
法二:select top 0 * into b from a '_lyoVP
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) L'BDS*
insert into b(a, b, c) select d,e,f from b; 5bYU(]
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) &=Gz[1
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 jrbEJ.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. W2D^%;mw
4、说明:子查询(表名1:a 表名2:b) GpMKOjVm|
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) AON";&dLq-
5、说明:显示文章、提交人和最后回复时间 X/gIH/
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b gbsRf&4h
6、说明:外连接查询(表名1:a 表名2:b) y>Zvos e
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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7、说明:在线视图查询(表名1:a ) 1P.
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select * from (SELECT a,b,c FROM a) T where t.a > 1; W=c7>s0>
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 Nwr.mtvh
select * from table1 where time between time1 and time2 jL(=<R(~y
select a,b,c, from table1 where a not between 数值1 and 数值2 -wH#B<'
9、说明:in 的使用方法 6vbWe@#U/
select * from table1 where a [not] in ('值1','值2','值4','值6') nfJ|&'T
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >@KQ )p' `
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) kTb.I;S
11、说明:四表联查问题: <W~5;m
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 ..... *;"N kCf
12、说明:日程安排提前五分钟提醒 bY|%ois4
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }__g\?Yf
13、说明:一条sql 语句搞定数据库分页 R7;SZo
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 |R8=yO%(
14、说明:前10条记录 (~:k70V5
select top 10 * form table1 where 范围 T]Gxf"mK
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.) C)~YWx@v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) x%23oPM
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 "u~l+aW0
(select a from tableA ) except (select a from tableB) except (select a from tableC) Tf7$PSupP
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() r(h&=&T6
18、说明:随机选择记录 BIEc4k5(
select newid() a/;u:"
19、说明:删除重复记录 Y]/(R"-2G
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) v_)a=I%o&2
20、说明:列出数据库里所有的表名 IMIZ#/
select name from sysobjects where type='U' Fh9%5-t:J
21、说明:列出表里的所有的 SlB,?R2
select name from syscolumns where id=object_id('TableName') R $HIJM
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 j/4N
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type )8kcOBG^L
显示结果: },KY9w
type vender pcs /e1m1 B
电脑 A 1 )f-u x5
电脑 A 1 F`SOF O
光盘 B 2 W{O:j
光盘 A 2 8J{I6nPF
手机 B 3 8>S"aHt 7
手机 C 3 YLmzMD>
23、说明:初始化表table1 u
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TRUNCATE TABLE table1 ] as_7
24、说明:选择从10到15的记录 -ZFeE[Z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5JW+&XA
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三、技巧 W6ZXb_X
1、1=1,1=2的使用,在SQL语句组合时用的较多 aehGT|
"where 1=1" 是表示选择全部 "where 1=2"全部不选, m(>_C~rGN
如: Xt~`EN
if @strWhere !='' ZZOBMF7
begin v+U(
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Xoyk 'T]-
end qIcQPJn!}
else #u~s,F$De
begin g
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' LI_>fuv"8
end ^'.=&@i-
我们可以直接写成 sUN>uroi !
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere >8Wvz.Nq/
2、收缩数据库 "'h?O*V]u{
--重建索引 $gT+Ue|7
DBCC REINDEX :-ZE~bHJ
DBCC INDEXDEFRAG p.^mOkpt
--收缩数据和日志 z"*X/T
DBCC SHRINKDB UZ0fw@R M
DBCC SHRINKFILE IG0$OtG
3、压缩数据库 :VP4|H#SP
dbcc shrinkdatabase(dbname) nkTH#WTfR
4、转移数据库给新用户以已存在用户权限 -NtT@ +AE
exec sp_change_users_login 'update_one','newname','oldname' [Av#Z)R
go fN~kdm.
5、检查备份集 0h-holUf}~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' biG=4?Xl
6、修复数据库 ^0"NcOzzxl
ALTER DATABASE [dvbbs] SET SINGLE_USER zqfv|3-!}
GO rGuhYYvK
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK []:;8fY
GO h^^zR)EVb
ALTER DATABASE [dvbbs] SET MULTI_USER 4[a?..X
GO yaD<jc(O
7、日志清除 hDJq:g
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SET NOCOUNT ON r7Bv?M^!
DECLARE @LogicalFileName sysname, `)e;bLP
@MaxMinutes INT, |7]7~ 6l
@NewSize INT Ou</{l/
USE tablename -- 要操作的数据库名 `fh^[Q|4n0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -QjdL9\[c7
@MaxMinutes = 10, -- Limit on time allowed to wrap log. J_YbeZ]
@NewSize = 1 -- 你想设定的日志文件的大小(M) pA)!40kz
-- Setup / initialize {k] 2h4 &h
DECLARE @OriginalSize int Yh_H$uW
SELECT @OriginalSize = size fiz2544
FROM sysfiles .o91^jt
WHERE name = @LogicalFileName mbxJS_P
SELECT 'Original Size of ' + db_name() + ' LOG is ' + GHj1G,L@\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *@o@>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~t[ #p:
FROM sysfiles ?g%5 d
WHERE name = @LogicalFileName E]w1!Ah M
CREATE TABLE DummyTrans (-*NRY3*
(DummyColumn char (8000) not null) Q:eIq<erY
DECLARE @Counter INT, t+Kxww58
@StartTime DATETIME, C-d|;R}Ww
@TruncLog VARCHAR(255) }qmBn`3R
SELECT @StartTime = GETDATE(), 8^M5k%P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _Z+tb]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (A O]f fBU
EXEC (@TruncLog) r_p9YS@I
-- Wrap the log if necessary. r9z_8#cR
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 21D4O,yCe
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }HtP8F8!x
AND (@OriginalSize * 8 /1024) > @NewSize kv&%$cA
BEGIN -- Outer loop. N
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SELECT @Counter = 0 qJ|ByZ.N+
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) [1B F8:
BEGIN -- update 4"1OtBU3
INSERT DummyTrans VALUES ('Fill Log') D}'g4Ag
DELETE DummyTrans &i"33.#]
SELECT @Counter = @Counter + 1 jm&?;~>O
END 16/+ O$#y
EXEC (@TruncLog) <_@ K4zV
END 6}
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + KK4>8zGR
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *6 -;iT8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Onb*nm
FROM sysfiles _?>!Bz
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WHERE name = @LogicalFileName XRXKO>4q
DROP TABLE DummyTrans 7vUfA"
SET NOCOUNT OFF c_clpMx=
8、说明:更改某个表 v'i"Q
exec sp_changeobjectowner 'tablename','dbo' w,TyV%b[_
9、存储更改全部表 !+Z"7e
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Ntr5Q
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@OldOwner as NVARCHAR(128), sj a;NL
@NewOwner as NVARCHAR(128) /+4Dq4{t)
AS u /!U/|
DECLARE @Name as NVARCHAR(128) ^4(CO[|c~
DECLARE @Owner as NVARCHAR(128) 6i[\?7O'0
DECLARE @OwnerName as NVARCHAR(128) QT{$2 7;
DECLARE curObject CURSOR FOR GlP
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select 'Name' = name, S_LY>k?
'Owner' = user_name(uid) dVc;Tt
from sysobjects q# gZ\V$I
where user_name(uid)=@OldOwner oc'#sE
order by name HRIf)n&~f
OPEN curObject *V#v6r7<Y/
FETCH NEXT FROM curObject INTO @Name, @Owner G}ElQD
WHILE(@@FETCH_STATUS=0) W=M&U
BEGIN |57KTiiNLI
if @Owner=@OldOwner /{ YUM~
begin UT[nzbG
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @v_E'
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exec sp_changeobjectowner @OwnerName, @NewOwner q)gZo[]~
end W>
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-- select @name,@NewOwner,@OldOwner idnn%iO
FETCH NEXT FROM curObject INTO @Name, @Owner &:=
END Gp9>R~$
close curObject o O%!P<