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。 sdXchVC
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一、基础 ~O./A-l
1、说明:创建数据库 PTpCiiA@
CREATE DATABASE database-name $aXYtHI
2、说明:删除数据库 .ZQXY%g
drop database dbname 2mj>,kS?c
3、说明:备份sql server 4mBM5Tv
--- 创建 备份数据的 device UlN}SddI9
USE master /Y\q&}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #9"lL1
--- 开始 备份 b N>Ar
BACKUP DATABASE pubs TO testBack rf$[8d
4、说明:创建新表 \2@9k`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) J=^5GfM)J
根据已有的表创建新表: $a\X(okx
A:create table tab_new like tab_old (使用旧表创建新表) tvzO)&)$
B:create table tab_new as select col1,col2... from tab_old definition only hhjsg?4uL
5、说明:删除新表 *X|%H-Q:H`
drop table tabname Dh{P23}
6、说明:增加一个列 FGwgSrXL7
Alter table tabname add column col type ,V4pFQzL
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。 QKz2ONV=)
7、说明:添加主键: Alter table tabname add primary key(col) Q(8W5Fb?
说明:删除主键: Alter table tabname drop primary key(col) z5:3.+M5
8、说明:创建索引:create [unique] index idxname on tabname(col....) 6x;"T+BSSS
删除索引:drop index idxname ?1]B(V9nBq
注:索引是不可更改的,想更改必须删除重新建。 TKw>eGe
9、说明:创建视图:create view viewname as select statement Z-U3TrSI
删除视图:drop view viewname Grd9yLF
10、说明:几个简单的基本的sql语句 `n|k+tsC
选择:select * from table1 where 范围 n!b*GXb\
插入:insert into table1(field1,field2) values(value1,value2) $[=`*m
删除:delete from table1 where 范围 f}FJR6VO
更新:update table1 set field1=value1 where 范围 R<h0RKiM@
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! OK}8BY
排序:select * from table1 order by field1,field2 [desc] NVC$8imip
总数:select count as totalcount from table1 )[sSCt]
求和:select sum(field1) as sumvalue from table1 @izS_I,
平均:select avg(field1) as avgvalue from table1 ";0-9*I
最大:select max(field1) as maxvalue from table1 &E
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最小:select min(field1) as minvalue from table1 4f0dc\$
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11、说明:几个高级查询运算词 1^;&?E
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A: UNION 运算符 )./'RE+(k
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 6B?1d
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B: EXCEPT 运算符 0j/i):@
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 /_bM~g
C: INTERSECT 运算符 qn\>(&
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 GWShv\c}
注:使用运算词的几个查询结果行必须是一致的。 B T{({3
12、说明:使用外连接 uqy~hY
A、left outer join: p@znmn-
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ^h|'\-d\
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2gjA>ET`N
B:right outer join: 483vFLnF
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 zwHTtE
C:full outer join: `Sj8<O}
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 naB[0I&
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二、提升 XlNB9\"5
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) aR;Q^YJ+a
法一:select * into b from a where 1<>1 ?at~il$z'
法二:select top 0 * into b from a {la^useg[
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *KV]MdS
insert into b(a, b, c) select d,e,f from b; qdu:kA:]
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) 1-gX=8]]
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ma*9O |v^
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. z#*GPA8Em:
4、说明:子查询(表名1:a 表名2:b) kQBVx8Uq]
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) <~8W>Y\m
5、说明:显示文章、提交人和最后回复时间 qOa-@MN
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b oq<#
6、说明:外连接查询(表名1:a 表名2:b)
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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 ) ||,;07
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2W~2Hk=0+%
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 TT&!WbA-Hk
select * from table1 where time between time1 and time2 j({L6</x
select a,b,c, from table1 where a not between 数值1 and 数值2 Ap> n4~
9、说明:in 的使用方法 !!K=v7M
select * from table1 where a [not] in ('值1','值2','值4','值6') eaiz
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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 ~d5{Q?T)
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) sQH.}W$C
11、说明:四表联查问题: x[oYN9O
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... >"nk}@
12、说明:日程安排提前五分钟提醒 If#7SF)n'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1X9sx&5H
13、说明:一条sql 语句搞定数据库分页 4Y/!V[
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 uc"u@ _M
14、说明:前10条记录 q{JD]A :
select top 10 * form table1 where 范围 ZyWC_r!
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) O 1X
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Hm^p^,}_x
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 {S&&X&A`v
(select a from tableA ) except (select a from tableB) except (select a from tableC) mg;AcAS.o,
17、说明:随机取出10条数据 i\eykYc,
select top 10 * from tablename order by newid() _bz,G"w+:
18、说明:随机选择记录 Zd%\x[f9ck
select newid() Tp6ysjao
19、说明:删除重复记录 },L[bDOV07
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %E!0,y,:
20、说明:列出数据库里所有的表名 fu&]t8MJC
select name from sysobjects where type='U' 5Np. &
21、说明:列出表里的所有的 XZT( :(
select name from syscolumns where id=object_id('TableName') '}Y8a$(;V
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。 =gqZ^v&5U
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 ?3, *
显示结果: hg>YOf&RG
type vender pcs ! O>mu6:Rf
电脑 A 1 ";. 3+z
电脑 A 1 QtzHr
光盘 B 2 FxT
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光盘 A 2 liB>~DVC
手机 B 3 _0`O}
手机 C 3 K=>/(sWiq
23、说明:初始化表table1 U5PCj ]-Xt
TRUNCATE TABLE table1 %?$"oWmenS
24、说明:选择从10到15的记录 JZ7-?
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p 5'\< gQ
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三、技巧 `'QPe42
1、1=1,1=2的使用,在SQL语句组合时用的较多 t8[:}[Jx
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ZtT`_G&
如: pL-$Np] V
if @strWhere !='' j)5Vv
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begin i
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Q&LkST-i
end EkBM>*W
else GgYomR:
begin }?^G=IP4(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' eyWwE%
end DQ}]'*@?
我们可以直接写成 ]7O?c=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere -|kDa1knA
2、收缩数据库 Glr.)PA
--重建索引 sig_2;
DBCC REINDEX `F@yZ4L3S
DBCC INDEXDEFRAG M/qiA.C@W
--收缩数据和日志 Pg36'aTe%j
DBCC SHRINKDB lo#,zd~
DBCC SHRINKFILE >JMKEHl.q
3、压缩数据库 S'e2~-p0F
dbcc shrinkdatabase(dbname) I|:j~EY
4、转移数据库给新用户以已存在用户权限 aU! UY(
exec sp_change_users_login 'update_one','newname','oldname' G~Sfpf
go re*/JkDq3K
5、检查备份集 ;D7jE+
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' A!~o?ej
6、修复数据库 Kna'5L5"
ALTER DATABASE [dvbbs] SET SINGLE_USER l9h;dI{6
GO m~K]|]iqQ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |"<
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GO 8FITcK^
ALTER DATABASE [dvbbs] SET MULTI_USER )em.KbsPPF
GO AQ5v`xE4
7、日志清除 :KLD~k7yA(
SET NOCOUNT ON ^J_hkw~gO
DECLARE @LogicalFileName sysname, ^b~5zhY&
@MaxMinutes INT, `<n:D`{dZ
@NewSize INT -G 'lyH
USE tablename -- 要操作的数据库名 NC}#P<U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 11sW$@xs
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. O#\>j
@NewSize = 1 -- 你想设定的日志文件的大小(M) _u>>+6,p
-- Setup / initialize | |=Duk
DECLARE @OriginalSize int qu%s 7+
SELECT @OriginalSize = size 2'U9!.o
FROM sysfiles CmOb+:4@K
WHERE name = @LogicalFileName rWXW}Yg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + EiUV?Gvz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + P$Q&xN<#)
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' `^kST><
FROM sysfiles ?r<F\rBT7*
WHERE name = @LogicalFileName (% P=#vZ
CREATE TABLE DummyTrans s|T7)PgR
(DummyColumn char (8000) not null) =.a ]?&Yyh
DECLARE @Counter INT, O@rb4(
@StartTime DATETIME, pg)g&ifKl
@TruncLog VARCHAR(255) !*gAGt_
SELECT @StartTime = GETDATE(), jxaoQeac
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v2{s2kB=
DBCC SHRINKFILE (@LogicalFileName, @NewSize) sh2bhv]
EXEC (@TruncLog) j+hoj2(
-- Wrap the log if necessary. b*KZe[#M1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired $wTX
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) b3lpNJ J
AND (@OriginalSize * 8 /1024) > @NewSize `uHpj`EU
BEGIN -- Outer loop. G
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SELECT @Counter = 0 F948%?a
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {@AcL:Eit
BEGIN -- update xF;v 6d
INSERT DummyTrans VALUES ('Fill Log') 1\0@?6`^
DELETE DummyTrans r.;iO0[/
SELECT @Counter = @Counter + 1 Rjl __90
END :F=nb+HZ
EXEC (@TruncLog) `WS_*fJ5
END ~0|hobk
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2\de |'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~*Qpv&y)
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' x["
FROM sysfiles nif'l/@"
WHERE name = @LogicalFileName ]s@8I2_
DROP TABLE DummyTrans #7h fEAk
SET NOCOUNT OFF Y +54z/{
8、说明:更改某个表 %LHV 0u
exec sp_changeobjectowner 'tablename','dbo' rbbuSI
9、存储更改全部表 V?BVk8D};
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Pltju4.:C
@OldOwner as NVARCHAR(128), iGLYM-
@NewOwner as NVARCHAR(128) -d'|X`^nE
AS {2r7:nvR
DECLARE @Name as NVARCHAR(128) x~^I/$
DECLARE @Owner as NVARCHAR(128) |81N/]EER
DECLARE @OwnerName as NVARCHAR(128) D:tZiS=0
DECLARE curObject CURSOR FOR ycD.:w p\'
select 'Name' = name, 'Y\"^'OU\
'Owner' = user_name(uid) @98SC}}u
from sysobjects {C6;$#7P
where user_name(uid)=@OldOwner UE w3AO
order by name l$_rA~Mo
OPEN curObject z&,sm5Lb
FETCH NEXT FROM curObject INTO @Name, @Owner Po.BcytM
WHILE(@@FETCH_STATUS=0) \r,.hUp
BEGIN &Ld8Z9IeFp
if @Owner=@OldOwner WI_mJ/2
begin ]_8I_VcQ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) `0|&T;7
exec sp_changeobjectowner @OwnerName, @NewOwner L$Ar]O)
end JSK5x(GlH
-- select @name,@NewOwner,@OldOwner ,D,f9
FETCH NEXT FROM curObject INTO @Name, @Owner Zb;$ZUWQX
END O/oYaAlFF@
close curObject yuDd%
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deallocate curObject u#k,G`
GO &W//
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10、SQL SERVER中直接循环写入数据 BrMp_M
declare @i int | V,jd
set @i=1 ~j#6 goKn
while @i<30 8k?L{hF|nW
begin }AZx/[k
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insert into test (userid) values(@i) .BDRD~kB
set @i=@i+1 TJS1,3<
end %uqD\`-
小记存储过程中经常用到的本周,本月,本年函数 +\vY; !^
Dateadd(wk,datediff(wk,0,getdate()),-1) BV?N_/DXp
Dateadd(wk,datediff(wk,0,getdate()),6) U]
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Dateadd(mm,datediff(mm,0,getdate()),0) f?zK"
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) W;]UP$5l
Dateadd(yy,datediff(yy,0,getdate()),0) F6]!?@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4 ~YQ\4h=
上面的SQL代码只是一个时间段 Prz+kPP
Dateadd(wk,datediff(wk,0,getdate()),-1) :k(t/*Nl3
Dateadd(wk,datediff(wk,0,getdate()),6) 1'm`SRX#e
就是表示本周时间段. LE80`t>M#
下面的SQL的条件部分,就是查询时间段在本周范围内的: *1S.9L
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) _|wY[YJ[
而在存储过程中 x~Ly$A2p
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Z)T@`B6
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1"B9Z6jf