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。 Z6zLL
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一、基础 610u!_-
1、说明:创建数据库 )8taMC:H^
CREATE DATABASE database-name hltUf5m'b
2、说明:删除数据库 BI<(]`FP;s
drop database dbname J vl-=~
3、说明:备份sql server BM9:|}\J65
--- 创建 备份数据的 device .]0:`Y,;
USE master RWB]uHzE
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P_P~c~o
--- 开始 备份 2J Wp5
BACKUP DATABASE pubs TO testBack R|k!w]
4、说明:创建新表 &k`/jl;u
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )h]tKYx
根据已有的表创建新表: f[*g8p
A:create table tab_new like tab_old (使用旧表创建新表) vl!o^_70(
B:create table tab_new as select col1,col2... from tab_old definition only ? <w[ZWytm
5、说明:删除新表 t]{, 7.S
drop table tabname y#P_ }Kfo
6、说明:增加一个列 a# Uk:O!
Alter table tabname add column col type C,8@V`
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。 #^_7i)=~
7、说明:添加主键: Alter table tabname add primary key(col) F ~e}=Nb
说明:删除主键: Alter table tabname drop primary key(col) *l@T
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8、说明:创建索引:create [unique] index idxname on tabname(col....) (SCZ.G(>
删除索引:drop index idxname @.=2*e.z|b
注:索引是不可更改的,想更改必须删除重新建。 VrKLEN\
9、说明:创建视图:create view viewname as select statement bo??91B^7
删除视图:drop view viewname "HLh3L~
10、说明:几个简单的基本的sql语句 5>:p'zI
选择:select * from table1 where 范围 uG/b Cb+V
插入:insert into table1(field1,field2) values(value1,value2) KkJE-k*D+w
删除:delete from table1 where 范围 Oiw!d6"Ovq
更新:update table1 set field1=value1 where 范围 Ko!a`I2M}
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ]E*xn
排序:select * from table1 order by field1,field2 [desc] ;[7#h8
总数:select count as totalcount from table1 cef:>>6_
求和:select sum(field1) as sumvalue from table1 <899r \
平均:select avg(field1) as avgvalue from table1 F)50 6
最大:select max(field1) as maxvalue from table1 SbobXTbG
最小:select min(field1) as minvalue from table1 ?i\$U'2*z3
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11、说明:几个高级查询运算词 e63io0g>
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A: UNION 运算符 t&C0V|s79$
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。 m xy=3cUi
B: EXCEPT 运算符 yg%T{hyzH
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。 3P*"$ fH
C: INTERSECT 运算符 rY"EW"y
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。 ]Gl5Qf:+z
注:使用运算词的几个查询结果行必须是一致的。 R;w1& Z
12、说明:使用外连接 Z"G?+gM@
A、left outer join: ^.[+)0I
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。 .Pa6HA !
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 8WwLKZ}
B:right outer join: ab5i7@Ed
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。 3H5<w4yk
C:full outer join: 7':<I-Fm
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。 <*opVy^
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二、提升 VjSA&R
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) s3)T}52
法一:select * into b from a where 1<>1 >kV=h?]Y
法二:select top 0 * into b from a H"rIOoxf
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Bs-MoT!
insert into b(a, b, c) select d,e,f from b; ."j*4
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) ZQ~EaI9R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 .a|ROjd!
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. EkP(]F
4、说明:子查询(表名1:a 表名2:b) &^ =Y76
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) (XQl2C
5、说明:显示文章、提交人和最后回复时间 >&|/4`HSB
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b oX-h7;SD
6、说明:外连接查询(表名1:a 表名2:b) {Yti
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3
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7、说明:在线视图查询(表名1:a ) 1c $iW>0K
select * from (SELECT a,b,c FROM a) T where t.a > 1; -PHqD
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 gjy:o5{vA*
select * from table1 where time between time1 and time2 q%FXox~b
select a,b,c, from table1 where a not between 数值1 and 数值2 7=4V1FS6i
9、说明:in 的使用方法 ld'Aaxl&
select * from table1 where a [not] in ('值1','值2','值4','值6') c6HH%|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 jhE3@c@pT
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) v?4MndR
11、说明:四表联查问题: j`"cU$NRM
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 ..... _MGhG{p7t
12、说明:日程安排提前五分钟提醒 D?cE$P
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |R>I#NO5
13、说明:一条sql 语句搞定数据库分页 h!1CsLd[
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 K/LoHWy+n*
14、说明:前10条记录 jF%l\$)/
select top 10 * form table1 where 范围 @xAfD{}f!
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) g8;JpP w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) SZC1$..2T
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 5,?Au
(select a from tableA ) except (select a from tableB) except (select a from tableC) j=w`%nh4"f
17、说明:随机取出10条数据 s KOy6v
select top 10 * from tablename order by newid() QLyBP!X-
18、说明:随机选择记录 PF-"^2&_
select newid() 2ZFp(e^%
19、说明:删除重复记录 JOH=)+xj
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) LwIX&\Ub
20、说明:列出数据库里所有的表名 L3X[; |v}
select name from sysobjects where type='U' h+Tt+Q\
21、说明:列出表里的所有的 f<( ysl1[
select name from syscolumns where id=object_id('TableName') 4+r26S,T
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。 Psu*t%nQ?A
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 24/ ^_Td
显示结果: 5I@2U vV8
type vender pcs @c{b\is2
电脑 A 1 o*|j}hnbv
电脑 A 1 }Gm/9@oKc
光盘 B 2 ,46k8%WW
光盘 A 2 <o\I C?A
手机 B 3 =Qw`F0t
手机 C 3 sMAu*
23、说明:初始化表table1 =ZN~*HLl}
TRUNCATE TABLE table1 L-(.v*
24、说明:选择从10到15的记录 fmq9u(!R
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ZfN%JJOz(
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三、技巧 Zae$M0)
1、1=1,1=2的使用,在SQL语句组合时用的较多 HWT^u$a"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '#0'_9}
如: Mi_/
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if @strWhere !=''
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begin fP:g}Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Sj<WiQ%<
end xA2"i2k9
else ,_2ZKO/k$
begin ;-X5#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' + %07J6
end ln6Hr^@5
我们可以直接写成 `>cBR,)r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere weky
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2、收缩数据库 "i ;c )ZP
--重建索引 Do5)ilt
DBCC REINDEX *R6Ed
DBCC INDEXDEFRAG K0O&-v0"1
--收缩数据和日志 rSvQarT
DBCC SHRINKDB &?#G)suP
DBCC SHRINKFILE vmZyvJSE
3、压缩数据库 0?
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dbcc shrinkdatabase(dbname) /^<Uy3F[p
4、转移数据库给新用户以已存在用户权限 ,P9q[
exec sp_change_users_login 'update_one','newname','oldname' S(
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go u4a(AB>S
5、检查备份集 8/dx)*JCq
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' u:f.g?!`"
6、修复数据库 7U\GX
ALTER DATABASE [dvbbs] SET SINGLE_USER "?UBW5nM#
GO &z(E-w/S
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK L^0s
GO X)peY
ALTER DATABASE [dvbbs] SET MULTI_USER '{?7\+o.x
GO 69$[yt>KYz
7、日志清除 hln.EAW'Yc
SET NOCOUNT ON Yq?FiE0
DECLARE @LogicalFileName sysname, VgO:`bDF
@MaxMinutes INT, @H^Yf
@NewSize INT <,!e*V*U
USE tablename -- 要操作的数据库名 AsW!GdIN
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hc;8Vsa
@MaxMinutes = 10, -- Limit on time allowed to wrap log. RrGFGn{
@NewSize = 1 -- 你想设定的日志文件的大小(M) MIJ^n(-G
-- Setup / initialize vP{22P
DECLARE @OriginalSize int 58@YWvAk
SELECT @OriginalSize = size EBX+fzjQo
FROM sysfiles >qBQfz:U>
WHERE name = @LogicalFileName hY@rt,! 8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Io81zA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + M_wj>NXZ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' #DI%l`B
FROM sysfiles U- UD27
WHERE name = @LogicalFileName z_^Vgb]
CREATE TABLE DummyTrans l$~3_3+
(DummyColumn char (8000) not null) eiV[y^?
DECLARE @Counter INT, eI7FbOze
@StartTime DATETIME, Hq*\,`b&
@TruncLog VARCHAR(255) uwcm%N;I"
SELECT @StartTime = GETDATE(), Gb\Nqx(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8AK=FX&@&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0Y81B;/F
EXEC (@TruncLog) #ONad0T;
-- Wrap the log if necessary. .W#-Cl&n8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired + S^OzCGk
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (HW!!xM
AND (@OriginalSize * 8 /1024) > @NewSize J7`fve
BEGIN -- Outer loop. }j/($,
SELECT @Counter = 0 &]'{N69@d?
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Mbua!m(0
BEGIN -- update /Jjub3>Q
INSERT DummyTrans VALUES ('Fill Log') ;|.^_Xs
DELETE DummyTrans J.r^"K\
SELECT @Counter = @Counter + 1 PYYK R
END wMB. p2
EXEC (@TruncLog) ?9Eshw2
END <GbF4\ue
SELECT 'Final Size of ' + db_name() + ' LOG is ' + S~9K'\vO
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3:Mq40]x
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' w@&4dau
FROM sysfiles _bi]Bpxf
WHERE name = @LogicalFileName Ca&5"aki
DROP TABLE DummyTrans 0Y_?r$M
SET NOCOUNT OFF {hzU
8、说明:更改某个表 (|<e4HfZL
exec sp_changeobjectowner 'tablename','dbo' 0@K?'6
9、存储更改全部表 'Olp2g8=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch UbD1h_b
@OldOwner as NVARCHAR(128), =r3 %jWH6
@NewOwner as NVARCHAR(128) O]\6Pv@N
AS GESEj%R/b
DECLARE @Name as NVARCHAR(128) F~`Yh6v
DECLARE @Owner as NVARCHAR(128) p5C:MA~*
DECLARE @OwnerName as NVARCHAR(128) )AxgKBW
DECLARE curObject CURSOR FOR F%t_9S,)O
select 'Name' = name, ADTx _tE
'Owner' = user_name(uid) /!l$Y?
from sysobjects b?p <y`
where user_name(uid)=@OldOwner X0\2q D
order by name -bN;nSgb
OPEN curObject )"W(0M]>
FETCH NEXT FROM curObject INTO @Name, @Owner Z r}5)ZR.
WHILE(@@FETCH_STATUS=0) _.9):i2<SF
BEGIN x}Y
if @Owner=@OldOwner -VqZw&"
begin tai=2,'
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g[Z$\A?ZbZ
exec sp_changeobjectowner @OwnerName, @NewOwner uANG_sX^n
end jT~PwDSFt3
-- select @name,@NewOwner,@OldOwner 6zmt^U
FETCH NEXT FROM curObject INTO @Name, @Owner %V,2,NCd
END MM}lW-q;
close curObject *&f^R}O
deallocate curObject t<)Cbple\
GO L\cd=&b`
10、SQL SERVER中直接循环写入数据 JnWG_|m)
declare @i int 1S&GhJ<wJ
set @i=1 #H'j;=]:
while @i<30 _2eRH@T
begin 6zo'w Wc3
insert into test (userid) values(@i) LW={| 3}
set @i=@i+1 P=.yXirm?
end VH.mH<
小记存储过程中经常用到的本周,本月,本年函数 !Ez5@
Dateadd(wk,datediff(wk,0,getdate()),-1) !e8OC9_x
Dateadd(wk,datediff(wk,0,getdate()),6) wLF;nzv
Dateadd(mm,datediff(mm,0,getdate()),0) 3pxZk%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;_o1{?~
Dateadd(yy,datediff(yy,0,getdate()),0) uwQ~4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) PQl^jS
上面的SQL代码只是一个时间段 lO
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Dateadd(wk,datediff(wk,0,getdate()),-1) U9<AL.
Dateadd(wk,datediff(wk,0,getdate()),6) Fgx{ s%&-
就是表示本周时间段. uPVM>xf>w
下面的SQL的条件部分,就是查询时间段在本周范围内的: Vs[A
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ',7LVT7
而在存储过程中 eGwO!Lv}B
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Mnu8d:$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) pyvH [