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。 ]=vRjw
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一、基础 XOT|:
1、说明:创建数据库 ;D|g5$OE&
CREATE DATABASE database-name >SW c
2、说明:删除数据库 RYZM_@5$t
drop database dbname Nq"J[l*+g
3、说明:备份sql server iyTKy+3A
--- 创建 备份数据的 device cP^c}e*;NS
USE master JmF:8Q3H
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' C Xh>'K
--- 开始 备份 ~nRbb;M
BACKUP DATABASE pubs TO testBack "5@\"L
4、说明:创建新表 b^R_8x
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X}ft7;Jpy
根据已有的表创建新表: IiM=Z=2
A:create table tab_new like tab_old (使用旧表创建新表) ZmAo9>'Kg
B:create table tab_new as select col1,col2... from tab_old definition only MuF{STE>->
5、说明:删除新表
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drop table tabname zbAyYMtEk
6、说明:增加一个列 mGh8/Xt
Alter table tabname add column col type !SdP<{[
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。 s|D[_N!|
7、说明:添加主键: Alter table tabname add primary key(col) irF+(&q]jh
说明:删除主键: Alter table tabname drop primary key(col) k{J\)z
8、说明:创建索引:create [unique] index idxname on tabname(col....) j7yUya&
删除索引:drop index idxname \{.c0
注:索引是不可更改的,想更改必须删除重新建。 "L+NN|
9、说明:创建视图:create view viewname as select statement NX8.
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删除视图:drop view viewname "{x+ \Z\
10、说明:几个简单的基本的sql语句 ?X@uR5?{
选择:select * from table1 where 范围 46D_K
插入:insert into table1(field1,field2) values(value1,value2) h3j`X'
删除:delete from table1 where 范围 < Y)A ez
更新:update table1 set field1=value1 where 范围 qlC4&82=Q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! o#hFK'&~
排序:select * from table1 order by field1,field2 [desc] G;AJBs>Y}
总数:select count as totalcount from table1 -u~AY#*
求和:select sum(field1) as sumvalue from table1 B4{F)Zb
平均:select avg(field1) as avgvalue from table1 #D^(dz*
最大:select max(field1) as maxvalue from table1 1AQ3<
最小:select min(field1) as minvalue from table1 s&M#]8x;x
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11、说明:几个高级查询运算词 x.>&|Ej
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A: UNION 运算符 UcWf
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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。 7~H"m/;U&
B: EXCEPT 运算符 y4,t=Gq7^
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。 JfzfxfM
C: INTERSECT 运算符 s]Z++Lh<{
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。 Id{Ix(O
注:使用运算词的几个查询结果行必须是一致的。 3bagL)'iz
12、说明:使用外连接 G$t:#2
A、left outer join: I@ D<rjR
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 : 2A\X' @
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +T HBPEq
B:right outer join: xG|lmYt76
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。
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C:full outer join: e?<$H\
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。 dC?l%,W
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二、提升 oiItQ4{<
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1 Ay.^f
法一:select * into b from a where 1<>1 !BR@"%hx
法二:select top 0 * into b from a mV|Z5 =f
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Yq%r\[%*
insert into b(a, b, c) select d,e,f from b; &X)^G#
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) |z`AIScT
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 HjT -5>I7f
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. vlPViHF.
4、说明:子查询(表名1:a 表名2:b) v
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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) P]H4!}M
5、说明:显示文章、提交人和最后回复时间 a.up&g_$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !wIrI/P7#
6、说明:外连接查询(表名1:a 表名2:b) z`!f'I--!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c rGQY
7、说明:在线视图查询(表名1:a ) Mc6v
select * from (SELECT a,b,c FROM a) T where t.a > 1; jR"ACup(
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 ,p6o "-
select * from table1 where time between time1 and time2 90">l^HX=
select a,b,c, from table1 where a not between 数值1 and 数值2 G],W{<Pe
9、说明:in 的使用方法 Iy@6cd,)S
select * from table1 where a [not] in ('值1','值2','值4','值6') ]f*.C9Y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >Dq&[9,8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ha~}NO
11、说明:四表联查问题: zRgl`zREr
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 ..... afye$$X
12、说明:日程安排提前五分钟提醒 LuWY}ste
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 14yzGhA
13、说明:一条sql 语句搞定数据库分页 dyt.(2
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 #{zF~/Qq
14、说明:前10条记录 }h=3[pe}
select top 10 * form table1 where 范围 *u!l"0'\
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.) xvW# ~T]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) m,r>E%;Cj
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^{
(select a from tableA ) except (select a from tableB) except (select a from tableC) b#Vm;6BHD1
17、说明:随机取出10条数据 -o YJ&r
select top 10 * from tablename order by newid() 9.Yn]O
18、说明:随机选择记录 @Wd1+Yky
select newid() vn ^*
19、说明:删除重复记录 W=2#Q2)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ,m;G:3}48
20、说明:列出数据库里所有的表名 NQ,2pM<*-
select name from sysobjects where type='U' /}=cv>S5V
21、说明:列出表里的所有的 ^o Q^/v~
select name from syscolumns where id=object_id('TableName') p&ZLd`[
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。 Cd7l+~*Y
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 Y|aaZ|+
显示结果: |L~RC
type vender pcs %R?#Y1Tq;
电脑 A 1 [W=6NAd
电脑 A 1 B2,JfKk/
光盘 B 2 /0 86qB|
光盘 A 2 / a$B8,
手机 B 3 L!^^3vn
手机 C 3 lfte
23、说明:初始化表table1 HQV#8G#B
TRUNCATE TABLE table1 R^Y_i
24、说明:选择从10到15的记录 nh>lDfJV<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Z)G@ahOQ
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三、技巧 R9InUX"k
1、1=1,1=2的使用,在SQL语句组合时用的较多 gU@BEn}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, cB}6{c$_sW
如: ]SNcL[U
if @strWhere !='' \(ju0qFqH
begin Hq "l`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _hi8mo
end nrCr9#
else _[S<Cb*1
begin )%~<EJ*&Z
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' u-HBmL
end =Y-mc#{8
我们可以直接写成 (r"2XXR
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ypw:Vp
2、收缩数据库 r$&WwH2^
--重建索引 N
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DBCC REINDEX .a
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DBCC INDEXDEFRAG ~A-D>.ZH
--收缩数据和日志 _rvO#h
DBCC SHRINKDB h|[oQ8)
DBCC SHRINKFILE 6>F]Z)]}
3、压缩数据库
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dbcc shrinkdatabase(dbname) YUQKy2
4、转移数据库给新用户以已存在用户权限 p=]z`t
exec sp_change_users_login 'update_one','newname','oldname' HMVyXulU
go D'oy%
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5、检查备份集 z#\YA]1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' CG[04y
6、修复数据库 U t.#h="
ALTER DATABASE [dvbbs] SET SINGLE_USER Un\
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GO {[[/*1r|
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK [PL]!\NJ
GO Q a3+ 9
ALTER DATABASE [dvbbs] SET MULTI_USER gR@,"6b3
GO )jed@?
7、日志清除 a_o99lP
SET NOCOUNT ON 3nX={72<b
DECLARE @LogicalFileName sysname, _BBs{47{E
@MaxMinutes INT, oE'Flc.
@NewSize INT {Zrf>ST
USE tablename -- 要操作的数据库名 v_NL2eQ~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 = K3NKPUI
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ==Bxv:6
@NewSize = 1 -- 你想设定的日志文件的大小(M) Kp%:\s,lO
-- Setup / initialize Yo[Pu< zR
DECLARE @OriginalSize int g\=e86
SELECT @OriginalSize = size ]TIBy "3
FROM sysfiles E*{_=pX
WHERE name = @LogicalFileName T {zz3@2?
SELECT 'Original Size of ' + db_name() + ' LOG is ' + +/DT#}JE
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \wxLt}T-Q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Y@Ti2bI`v
FROM sysfiles #qg(DgH
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WHERE name = @LogicalFileName 29r (Y
CREATE TABLE DummyTrans b]Z>P{ j
(DummyColumn char (8000) not null) ?qR11A};tG
DECLARE @Counter INT, [?nM)4d
@StartTime DATETIME, >^zbDU1wT
@TruncLog VARCHAR(255) RzN9pAe
SELECT @StartTime = GETDATE(), <F<jx"/)
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6;#Rd|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) x$=""?dd
EXEC (@TruncLog) )_\q)t"=
-- Wrap the log if necessary. ?`U=Ps
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Vc$y^|=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {q|Om?@
AND (@OriginalSize * 8 /1024) > @NewSize /'Q2TLy=
BEGIN -- Outer loop. jRNDi_u?Wb
SELECT @Counter = 0 \2VYDBi?|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) J0,;F9<C#X
BEGIN -- update )|j?aVqZ
INSERT DummyTrans VALUES ('Fill Log') pW1(1M)[%Z
DELETE DummyTrans 8N9X1Mb|
SELECT @Counter = @Counter + 1 g<PglRr"
END `F4gal^ ^
EXEC (@TruncLog) )l[bu6bM
END /L*JHNu"_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;cp,d~m rf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + C] >?YR4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^]ig*oS\`
FROM sysfiles m\e?'-(s
WHERE name = @LogicalFileName 7j8Ou3
DROP TABLE DummyTrans ?yy,3:
SET NOCOUNT OFF i16kPU
8、说明:更改某个表 Q$8&V}jVW
exec sp_changeobjectowner 'tablename','dbo' *5d6Q
9、存储更改全部表 oJe`]_XZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch #gSLFM{p
@OldOwner as NVARCHAR(128), +wxDK A_
@NewOwner as NVARCHAR(128) (fcJp)D
AS .T\_4C
DECLARE @Name as NVARCHAR(128) SmVL?wf
DECLARE @Owner as NVARCHAR(128) ?z0N-A2C2
DECLARE @OwnerName as NVARCHAR(128) e]-%P(}Z
DECLARE curObject CURSOR FOR }0~X)Vgm(
select 'Name' = name, YuFR*W;$
'Owner' = user_name(uid) ^/fasl$#
from sysobjects %3@-.=
where user_name(uid)=@OldOwner M3Oqto<8"
order by name ][`% vj9r
OPEN curObject 6o<(,\ad[
FETCH NEXT FROM curObject INTO @Name, @Owner uS7kkzt-x
WHILE(@@FETCH_STATUS=0) 4}F~h
BEGIN 'b:e8m
if @Owner=@OldOwner t[o_!fmxZ
begin JasA
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) D`3`5.b
exec sp_changeobjectowner @OwnerName, @NewOwner -rlCE-S
end &gsBbQ+qA
-- select @name,@NewOwner,@OldOwner r$W%d[pB
FETCH NEXT FROM curObject INTO @Name, @Owner _)[UartKx
END +F+M[ef<ws
close curObject 0t7vg#v|
deallocate curObject il% u)NN
GO <.hutU*1
10、SQL SERVER中直接循环写入数据 o>\o=%D.a
declare @i int IPf>9#L
set @i=1 }/2M?W0
while @i<30 CD[}|N
begin ZQ{-6VCjl
insert into test (userid) values(@i) vwAtX($
set @i=@i+1 T{)_vQ
end 9qUkw&}H
小记存储过程中经常用到的本周,本月,本年函数 &yG5w4<
Dateadd(wk,datediff(wk,0,getdate()),-1) XIn,nCY;
Dateadd(wk,datediff(wk,0,getdate()),6) 8p]9A,Uq&
Dateadd(mm,datediff(mm,0,getdate()),0) xJ9aFpTC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |enb5b78
Dateadd(yy,datediff(yy,0,getdate()),0) 3,- [lG@o
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #mkf2Z=t-
上面的SQL代码只是一个时间段 Rqr>B(|
Dateadd(wk,datediff(wk,0,getdate()),-1) J";4+wA7
Dateadd(wk,datediff(wk,0,getdate()),6) 2'u%
就是表示本周时间段. Xyr'rm5+b
下面的SQL的条件部分,就是查询时间段在本周范围内的: _!,Ees=b
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %77uc9}
而在存储过程中 9{
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) N(V_P[]"*,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~;#sj&~