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。 a{6|[aR
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一、基础 YZJP7nN
1、说明:创建数据库 RH 0a\RC!G
CREATE DATABASE database-name +N!{(R:"v}
2、说明:删除数据库 he6)
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drop database dbname Ct33S+y
3、说明:备份sql server '0?E|B]Cp%
--- 创建 备份数据的 device bHG>SW\]`?
USE master ?':'zT
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~hX'FV
--- 开始 备份 ~Q]M_,`M
BACKUP DATABASE pubs TO testBack FkkB#Jk4
4、说明:创建新表 0`=?ig_
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) $~\qoW<
根据已有的表创建新表: D(GHkS*0q
A:create table tab_new like tab_old (使用旧表创建新表) 6lFs N2
B:create table tab_new as select col1,col2... from tab_old definition only K 6Ua~N^
5、说明:删除新表 >,1LBM|0u
drop table tabname [K QZHIe
6、说明:增加一个列 T!E LH!
Alter table tabname add column col type S-dV
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 rrq-so1u}
7、说明:添加主键: Alter table tabname add primary key(col) 'D{abm0
说明:删除主键: Alter table tabname drop primary key(col) Q)8t;Kx
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7 4UE-H)
删除索引:drop index idxname wAPdu y[
注:索引是不可更改的,想更改必须删除重新建。 );LwWKa
9、说明:创建视图:create view viewname as select statement PUArKBYM-
删除视图:drop view viewname zvg&o)/[
10、说明:几个简单的基本的sql语句 {S~$\4vC!
选择:select * from table1 where 范围 34+}u,=
插入:insert into table1(field1,field2) values(value1,value2) Fb-TCq1y#
删除:delete from table1 where 范围 9|DC<Zn&B#
更新:update table1 set field1=value1 where 范围 ;c}];ZU3G
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! +r"$?bw'
排序:select * from table1 order by field1,field2 [desc] W5{e.eI}|
总数:select count as totalcount from table1 n&JP/P3Y
求和:select sum(field1) as sumvalue from table1 Ss}0.5Bq
平均:select avg(field1) as avgvalue from table1 b@Cvs4
最大:select max(field1) as maxvalue from table1 ^5F/=TtE G
最小:select min(field1) as minvalue from table1 i>}z$'X
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11、说明:几个高级查询运算词 E$
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A: UNION 运算符 N<%,3W_-_
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。 : Tl?yGF
B: EXCEPT 运算符 N<WFe5
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。 tDVdl^#
C: INTERSECT 运算符 6Rj
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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。 > kT~X ,o
注:使用运算词的几个查询结果行必须是一致的。 3dLz=.=)'
12、说明:使用外连接 pj6Cvq4bD
A、left outer join: MIJ~j><L
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。 TMBdneS-s
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 I&c#U+-A'
B:right outer join: on$a]zx'@
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 nm.d.A/]Z
C:full outer join: %{"STbO #>
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 }vIm C [
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二、提升 xOlkG*3c
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) g11K?3*%Q
法一:select * into b from a where 1<>1 kzu=-@s
法二:select top 0 * into b from a )2S\:&x
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :z7!X.*
insert into b(a, b, c) select d,e,f from b; V"XN(Fd^
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ,8seoX^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 D?R z|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. cCIEG e6
4、说明:子查询(表名1:a 表名2:b) W#Z]mt B
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) tK*f8X+q
5、说明:显示文章、提交人和最后回复时间 ^=j$~*(LmX
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b I5,Fh>
6、说明:外连接查询(表名1:a 表名2:b) 3IIlAzne;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c z7o59&
7、说明:在线视图查询(表名1:a ) V
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select * from (SELECT a,b,c FROM a) T where t.a > 1;
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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 Z)~2{)
select * from table1 where time between time1 and time2 Z "u/8
select a,b,c, from table1 where a not between 数值1 and 数值2 $9/r*@bu8d
9、说明:in 的使用方法 TEtZPGFl
select * from table1 where a [not] in ('值1','值2','值4','值6') B=7L+6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 q!4dK4`#5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Wu(GC]lTG
11、说明:四表联查问题: 6gXc-}dp
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 ..... F(9T;F
12、说明:日程安排提前五分钟提醒 <Coh
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *0@e_h
13、说明:一条sql 语句搞定数据库分页 /VQ<}S[k}-
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 K""04Ew*pV
14、说明:前10条记录 [@czvPi
select top 10 * form table1 where 范围 AyUVsIuPT=
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.) >8Y >B)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B4C`3@a
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 $Fj7'@1(
(select a from tableA ) except (select a from tableB) except (select a from tableC) =z+zg^wsT
17、说明:随机取出10条数据 OB%y'mo7]
select top 10 * from tablename order by newid() fi1UUJ0
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18、说明:随机选择记录 ]So%/rOvX
select newid() Qa=;Elp:[
19、说明:删除重复记录 })Jp5vv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 6*E7}
20、说明:列出数据库里所有的表名 s$;v )w$
select name from sysobjects where type='U' _F9
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21、说明:列出表里的所有的 ;%}
select name from syscolumns where id=object_id('TableName') J{Jxb1:c
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。 q!n|Ju<
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 4{V=X3,x
显示结果: <Ip}uy[Y
type vender pcs j,Y=GjfGM
电脑 A 1 chy7hPxC;
电脑 A 1 )u$A!+fo
光盘 B 2 btOC\bUMfD
光盘 A 2 N^)OlH
手机 B 3 ZHT.+X:_
手机 C 3 xAI<<[-
23、说明:初始化表table1 <}ev Ow2
TRUNCATE TABLE table1 /T?['#:r-)
24、说明:选择从10到15的记录 hikun2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ji "*=i
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三、技巧 Cpl\}Qn
1、1=1,1=2的使用,在SQL语句组合时用的较多 lH[N*9G(
"where 1=1" 是表示选择全部 "where 1=2"全部不选, e>[QF+e)y
如: %}@^[E)
if @strWhere !='' &\A$Rj)
begin F[lHG,g-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere x|Dj
end |cH\w"DcXw
else TSOt$7-
begin p8Pvctc
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?@ O[$9y
end wXP1tM8T
我们可以直接写成 cla4%|kq3Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KF.?b]
2、收缩数据库 $ysC)5q.
--重建索引 iVD9MHT4
DBCC REINDEX 83@+X4ptp
DBCC INDEXDEFRAG VGSe<6Hh
--收缩数据和日志 G 2mv6xK'
DBCC SHRINKDB a 3HS!/
DBCC SHRINKFILE XG0,@Ly
3、压缩数据库 'vXrA
dbcc shrinkdatabase(dbname) Y!KGJ^.mF
4、转移数据库给新用户以已存在用户权限 b[$>HB_Na
exec sp_change_users_login 'update_one','newname','oldname' E0YXgQa
go l)?c3
5、检查备份集 {w2<;YXj!
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' F](kU#3"S
6、修复数据库 DpA)Z??
ALTER DATABASE [dvbbs] SET SINGLE_USER yY!jkRq%w
GO 6d_l[N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK {W0@lMrD
GO J &c}z4
ALTER DATABASE [dvbbs] SET MULTI_USER E@?jsN7
GO "`lRX
7、日志清除 # H4dmnV
SET NOCOUNT ON ruoiG?:T
DECLARE @LogicalFileName sysname, "B.l j)
@MaxMinutes INT, >LjvMj ]
@NewSize INT }hGbF"clqg
USE tablename -- 要操作的数据库名 419t"1b
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 L%!jj7,9-
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #CM2FN:W
@NewSize = 1 -- 你想设定的日志文件的大小(M) h5F1mr1Sa
-- Setup / initialize @+\OoOK<L
DECLARE @OriginalSize int $v+g3+7
SELECT @OriginalSize = size X/?3ifP6I
FROM sysfiles 3o6N&bQ b
WHERE name = @LogicalFileName Qq5)|m
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]R0^
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + f F?=W
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7[Y<5T]
FROM sysfiles K2&pTA~OR
WHERE name = @LogicalFileName ^NP" m
CREATE TABLE DummyTrans ^Xh9:OBF
(DummyColumn char (8000) not null) TK'(\[E
DECLARE @Counter INT, t&ngOF
@StartTime DATETIME, E_FseR6
@TruncLog VARCHAR(255) TN&1C8xr
SELECT @StartTime = GETDATE(), *NDzU%X8
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ^58'*13ZL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ) ><{A
EXEC (@TruncLog) .t\5H<z
-- Wrap the log if necessary. 4%B${zP(.}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m|'TPy
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)
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AND (@OriginalSize * 8 /1024) > @NewSize ?!Y2fK=h0
BEGIN -- Outer loop. N~SG=\rP;o
SELECT @Counter = 0 "xw2@jGpG
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Z[|(}9v?~
BEGIN -- update !IP[C?(nB
INSERT DummyTrans VALUES ('Fill Log') ^/c&Ud
DELETE DummyTrans =8[HC}s|$
SELECT @Counter = @Counter + 1 aVd{XVE
END ~W!sxM5(*
EXEC (@TruncLog) LTrn$k3}
END O0wD"V^W
SELECT 'Final Size of ' + db_name() + ' LOG is ' + --y.q~d
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I( pU_7mw
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' P*G&pitT
FROM sysfiles kpEES{f
WHERE name = @LogicalFileName V+_L9
DROP TABLE DummyTrans {4UlJ,Z.n
SET NOCOUNT OFF "{|9Yis=
8、说明:更改某个表 74QWGw`,
exec sp_changeobjectowner 'tablename','dbo' )'92{-A0
9、存储更改全部表 wOINcEdx
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g {wDI7"<q
@OldOwner as NVARCHAR(128), tFXG4+$D
@NewOwner as NVARCHAR(128) Ot5
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AS W&)OiZN
DECLARE @Name as NVARCHAR(128) t[%9z6t
DECLARE @Owner as NVARCHAR(128) DqbN=[!X~n
DECLARE @OwnerName as NVARCHAR(128) [K,&s8N5
DECLARE curObject CURSOR FOR 6dV92:
select 'Name' = name, Wk`G+VR+
'Owner' = user_name(uid) Q']:k}y
from sysobjects \3Ys8umKq
where user_name(uid)=@OldOwner |0BmEF
order by name ,0;E_i7
OPEN curObject t/pHdxX*C7
FETCH NEXT FROM curObject INTO @Name, @Owner rJ K~kKG
WHILE(@@FETCH_STATUS=0) &!a[rvtZ+
BEGIN .F&\xa{
if @Owner=@OldOwner p\~ lPXK
begin \%f4)Qb
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 27}k63 \
exec sp_changeobjectowner @OwnerName, @NewOwner S-g`rTx
end $wAVM/u&
-- select @name,@NewOwner,@OldOwner H;%a1
FETCH NEXT FROM curObject INTO @Name, @Owner gtJUQu p2
END &H`yDrg6U
close curObject yD(0:g#
deallocate curObject =DUsQN!
GO 0~Z2$`(
10、SQL SERVER中直接循环写入数据 =#SKN\4
declare @i int YB.r-c"Y
set @i=1 JuKj
while @i<30 BB>3Kj:|
begin j'I$F1>Te
insert into test (userid) values(@i) K'7i$bl%
set @i=@i+1 h{VCx#!]
end bo`w(h_
小记存储过程中经常用到的本周,本月,本年函数 ZoF\1C ^
Dateadd(wk,datediff(wk,0,getdate()),-1) ^3 F[^#"
Dateadd(wk,datediff(wk,0,getdate()),6) 8tY],
Dateadd(mm,datediff(mm,0,getdate()),0) rer=o S
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 77.5
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Dateadd(yy,datediff(yy,0,getdate()),0) x/R|i%u-s
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) l0 rZril
上面的SQL代码只是一个时间段 -%NT)o
Dateadd(wk,datediff(wk,0,getdate()),-1) ma?$@]`k
Dateadd(wk,datediff(wk,0,getdate()),6) P10`X&
就是表示本周时间段. }2-{4JIq}
下面的SQL的条件部分,就是查询时间段在本周范围内的: Ay22-/C|@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) V.>'\b/#
而在存储过程中 n@Y`g{{e~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;XRLp:y
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |U>BXX P