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) \PW1b
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一、基础 Kggc9^ 7
1、说明:创建数据库 _c z$w5`
CREATE DATABASE database-name gN/kNck
2、说明:删除数据库 >D\jyd$wh&
drop database dbname mXSs:FqE!
3、说明:备份sql server L*(!P4S%}
--- 创建 备份数据的 device %&iY5A
USE master ["u:_2!4P
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' j}`XF?2D
--- 开始 备份 JK%UaEut=
BACKUP DATABASE pubs TO testBack .:~{+
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4、说明:创建新表 (drDC1\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) EGL7z`nt
根据已有的表创建新表: zObrp
A:create table tab_new like tab_old (使用旧表创建新表) #0*oj/
B:create table tab_new as select col1,col2... from tab_old definition only srGF=1_
5、说明:删除新表 (nDen5Q|
drop table tabname CMiE$yC
6、说明:增加一个列 WV8vDv1jt
Alter table tabname add column col type i-YSt5iq
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 :Z R5<Y>
7、说明:添加主键: Alter table tabname add primary key(col) U
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说明:删除主键: Alter table tabname drop primary key(col) J$D/-*/@
8、说明:创建索引:create [unique] index idxname on tabname(col....) _O$7*k
删除索引:drop index idxname Puq
注:索引是不可更改的,想更改必须删除重新建。 o>l/*i0I
9、说明:创建视图:create view viewname as select statement "\~d!"n|2
删除视图:drop view viewname Zl\$9Q_
10、说明:几个简单的基本的sql语句 -;Ij ,
选择:select * from table1 where 范围 q; ?Kmk
插入:insert into table1(field1,field2) values(value1,value2) />X"'G
删除:delete from table1 where 范围 SZVAf|]Yg
更新:update table1 set field1=value1 where 范围 6JB*brO
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! r.ib"W#4
排序:select * from table1 order by field1,field2 [desc] U)JwoO
总数:select count as totalcount from table1 J=?P`\h
求和:select sum(field1) as sumvalue from table1 xt zjFfq
平均:select avg(field1) as avgvalue from table1 @Rw]boC
最大:select max(field1) as maxvalue from table1 jU}iQM
最小:select min(field1) as minvalue from table1 L!LhH
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11、说明:几个高级查询运算词 bjr()NM1
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A: UNION 运算符 dr gCr:Gf
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 x:E:~h[.^
B: EXCEPT 运算符 }8Yu"P${Y
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。 nrM_ay
C: INTERSECT 运算符 PLueH/gC .
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。 .jv#<"DW
注:使用运算词的几个查询结果行必须是一致的。 ?'^dYQ4
12、说明:使用外连接 v\G+t2{
A、left outer join: |ERf3
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。 c>b{/92%
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 o^3X5})sv
B:right outer join: v/GZByco>
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。 iOdk)
C:full outer join: "KKw\i
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。 O"ebrv
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二、提升 7m.>2U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) y[DS$>E
法一:select * into b from a where 1<>1 oC~+K@S
法二:select top 0 * into b from a fA"9eUu
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^u+#x2$Mg
insert into b(a, b, c) select d,e,f from b; ~[Z,:=z
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) mO0}Go8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 .YlhK=d4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _W
4、说明:子查询(表名1:a 表名2:b) $g!iy'4n*
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) {:TOm0eK
5、说明:显示文章、提交人和最后回复时间 7srq~;j3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b gXvE^fE
6、说明:外连接查询(表名1:a 表名2:b) bWg!/K55
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R*l3 zn>
7、说明:在线视图查询(表名1:a ) 1'!%$D
select * from (SELECT a,b,c FROM a) T where t.a > 1; Lk]W?
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 6FFM-9*|[
select * from table1 where time between time1 and time2 f taa~h*
select a,b,c, from table1 where a not between 数值1 and 数值2 )?<V-,D
9、说明:in 的使用方法 FyWrb+_0v
select * from table1 where a [not] in ('值1','值2','值4','值6') 9P&{Xhs7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .W51Cup@&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;$g?W"
11、说明:四表联查问题: Sv\399(
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... )ml#2XP!f
12、说明:日程安排提前五分钟提醒 T_ga?G<
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 'B;n&tJ
13、说明:一条sql 语句搞定数据库分页 Wg=q lux-
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 a49t/
14、说明:前10条记录 * zc[t
select top 10 * form table1 where 范围 3a0% J'
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) F13vc~$Ky
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) i$6o>V6
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 B)BR
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(select a from tableA ) except (select a from tableB) except (select a from tableC) o]aMhSol
17、说明:随机取出10条数据 jGEmf<q&u
select top 10 * from tablename order by newid() |F49<7XB[~
18、说明:随机选择记录 Xu7lV
select newid() ]Q -.Y-J/O
19、说明:删除重复记录 zsr; 37
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) >9,LN;Ic
20、说明:列出数据库里所有的表名 9dFo_a*?
select name from sysobjects where type='U' 3|(3jIa
21、说明:列出表里的所有的 'iX y?l
select name from syscolumns where id=object_id('TableName') |4!G@-2V:I
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Bej k^V~
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type vu~7Z;y(<j
显示结果: ot,=.%O
type vender pcs 'DD~xCXE
电脑 A 1 eQJyO9$G
电脑 A 1 3/Dis)
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光盘 B 2 F- {hXM
光盘 A 2 D22A)0+_
手机 B 3
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手机 C 3 H`nd |
23、说明:初始化表table1 *})Np0k
TRUNCATE TABLE table1 >"[Nmx0;w
24、说明:选择从10到15的记录 dZ x
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ->'xjD
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三、技巧 tja7y"(]
1、1=1,1=2的使用,在SQL语句组合时用的较多 bO+e?&vQ%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LY2QKjgP
如: W?gelu]
if @strWhere !='' lz4M)pL^
begin #ds@!u+&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere <
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end M%2w[<-8c
else co*XW
begin gp-rTdN
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }1|FES
end ?ajVf./Ja
我们可以直接写成 \{54mM~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere GpCjoNcW{
2、收缩数据库 &R3#? 1,
--重建索引 IZ@M
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DBCC REINDEX sOm&7A?
DBCC INDEXDEFRAG {j%7/T{
--收缩数据和日志 o`.5NUn
DBCC SHRINKDB %[OZ;q& X
DBCC SHRINKFILE 8u"HW~~=
3、压缩数据库 OBf$0
dbcc shrinkdatabase(dbname) FSb4RuD9
4、转移数据库给新用户以已存在用户权限 6SEq 2
exec sp_change_users_login 'update_one','newname','oldname' !H(V%B%
go $*C'{&2
5、检查备份集 yc0_7Im?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -Xt0=3,
6、修复数据库 ^-,@D+eW
ALTER DATABASE [dvbbs] SET SINGLE_USER Nc*z?0wP
GO
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ivvm.7{
GO lL*"N|Y
ALTER DATABASE [dvbbs] SET MULTI_USER ASa)xf9
GO [#2X
7、日志清除 Z`>m
SET NOCOUNT ON @DK`#,
DECLARE @LogicalFileName sysname, #0c;2}D
@MaxMinutes INT, lI;ACF^
@NewSize INT Tua#~.3}J
USE tablename -- 要操作的数据库名 }Io5&ww:U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 eV\VR
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. U,V+qnS
@NewSize = 1 -- 你想设定的日志文件的大小(M) *rmM2{6
-- Setup / initialize S'=}eeG
DECLARE @OriginalSize int
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SELECT @OriginalSize = size uE'Kk8
FROM sysfiles C /w]B[H
WHERE name = @LogicalFileName *#j_nNM4
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -EG=}uT['b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _*n
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' k;
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FROM sysfiles }r|$\ms
WHERE name = @LogicalFileName qsdgG1<
CREATE TABLE DummyTrans |)%;B%
(DummyColumn char (8000) not null) Wo~;h(6
DECLARE @Counter INT, g1&q6wCg|
@StartTime DATETIME, > mEB,
@TruncLog VARCHAR(255) z)%]#QO
SELECT @StartTime = GETDATE(), pQk@
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {GG;/Ns{f-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) '1b4nj|<m
EXEC (@TruncLog) okH*2F(-
-- Wrap the log if necessary. 9
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Rg 5kFeS
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #pk
AND (@OriginalSize * 8 /1024) > @NewSize 5RR4jX]
BEGIN -- Outer loop. ageTv/
SELECT @Counter = 0 r tH
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) g])iU9)8
BEGIN -- update ,OBJ>_5
INSERT DummyTrans VALUES ('Fill Log') jAfqC@e
DELETE DummyTrans 0HDL;XY6
SELECT @Counter = @Counter + 1 `W2
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END xo#K_"E
EXEC (@TruncLog) B[fbP rM
END )^m"fQ+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + R+tQvxp#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + CM;B{*En
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ) h=[7}|
FROM sysfiles iIc/%<
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WHERE name = @LogicalFileName %nyZ=&u
DROP TABLE DummyTrans u|75r%p>
SET NOCOUNT OFF wS+j^
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8、说明:更改某个表 0}WDB_L
exec sp_changeobjectowner 'tablename','dbo' 7|(o=+Bt
9、存储更改全部表 !wH'dsriD
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch om8`^P/b
@OldOwner as NVARCHAR(128), +Os9}uKf
@NewOwner as NVARCHAR(128) &)!4rABn
AS v>sjS3
DECLARE @Name as NVARCHAR(128) U P*5M
DECLARE @Owner as NVARCHAR(128) ?P(U/DS8
DECLARE @OwnerName as NVARCHAR(128) @# GS4I
DECLARE curObject CURSOR FOR nRcy`A%
select 'Name' = name, 5QZ}KNJ|t~
'Owner' = user_name(uid) ;jFUtG
from sysobjects d t^Hd]+^\
where user_name(uid)=@OldOwner !nTI(--
order by name *`V r P
OPEN curObject R[}fr36>/
FETCH NEXT FROM curObject INTO @Name, @Owner !%/(a)B$^$
WHILE(@@FETCH_STATUS=0) mLDuizWI
BEGIN
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if @Owner=@OldOwner ebhV;Q.
begin -AwkP
set @OwnerName = @OldOwner + '.' + rtrim(@Name)
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exec sp_changeobjectowner @OwnerName, @NewOwner 9EWw
end @P<aTRy,f
-- select @name,@NewOwner,@OldOwner dlBr2 9
FETCH NEXT FROM curObject INTO @Name, @Owner N[kl3h%q
END A5RM&y
close curObject o>A']+`Eu
deallocate curObject _Q7]Dw/w\
GO {2LV0:k2
10、SQL SERVER中直接循环写入数据 m3=Cg$n
declare @i int qq>Qi (>
set @i=1 p']{WLDj2
while @i<30 .@@&q4=&
begin ~=?^v[T1
insert into test (userid) values(@i) d Y`P
set @i=@i+1 t(xe*xS
end #Ht;5p>5
小记存储过程中经常用到的本周,本月,本年函数 ko6[Ej:TBo
Dateadd(wk,datediff(wk,0,getdate()),-1) o':K4r;
Dateadd(wk,datediff(wk,0,getdate()),6) s,-}}6WO
Dateadd(mm,datediff(mm,0,getdate()),0) /}nq?Vf
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7E;`1lh7
Dateadd(yy,datediff(yy,0,getdate()),0) |l:,EA_v|
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) fHXz{,?/w
上面的SQL代码只是一个时间段 U_~r0
Dateadd(wk,datediff(wk,0,getdate()),-1) 8}?w%FsN#
Dateadd(wk,datediff(wk,0,getdate()),6) fk\hrVP
就是表示本周时间段. jRhRw;
下面的SQL的条件部分,就是查询时间段在本周范围内的: ksF4m_E>YB
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rAS2qt
而在存储过程中 Tfw5i,{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cQ(,M
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &_,.*tha