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。 rU4;yy*b
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一、基础 ^>wlj
1、说明:创建数据库
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CREATE DATABASE database-name _D 9/,n$
2、说明:删除数据库 p40;@gUug
drop database dbname *@I/TX'\rY
3、说明:备份sql server >:Y"DX-
--- 创建 备份数据的 device Q~R% |Q{&
USE master tm1#Lh0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' |)VNf.aJZ
--- 开始 备份 B>}B{qi|
BACKUP DATABASE pubs TO testBack z:^(#G{
4、说明:创建新表 C'~Eq3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lVv'_9yg
根据已有的表创建新表: ~xLo0EV"
A:create table tab_new like tab_old (使用旧表创建新表) oRo[WQla
B:create table tab_new as select col1,col2... from tab_old definition only ~4+ICCbH
5、说明:删除新表 ]z O6ESH
drop table tabname ;fW`#aE
6、说明:增加一个列 BOflhoUX
Alter table tabname add column col type y(ceEV
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。 23d*;ri5
7、说明:添加主键: Alter table tabname add primary key(col) redMlHM
说明:删除主键: Alter table tabname drop primary key(col) Sx:JuK@
8、说明:创建索引:create [unique] index idxname on tabname(col....) Wr3z%1
删除索引:drop index idxname P b-4$n2c
注:索引是不可更改的,想更改必须删除重新建。 4wKQs&:
9、说明:创建视图:create view viewname as select statement enGZb&
删除视图:drop view viewname ~9y/MR
10、说明:几个简单的基本的sql语句 9!_JV;2
选择:select * from table1 where 范围 r^7eK)XA_
插入:insert into table1(field1,field2) values(value1,value2) _z=ytt9D
删除:delete from table1 where 范围 YEa<zhO8
更新:update table1 set field1=value1 where 范围 B/*\Ih9y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! s
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排序:select * from table1 order by field1,field2 [desc] 8e5imei
总数:select count as totalcount from table1 }<qZXb1
求和:select sum(field1) as sumvalue from table1 CwM1
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平均:select avg(field1) as avgvalue from table1 e:l7 w3?O
最大:select max(field1) as maxvalue from table1 I`77[
最小:select min(field1) as minvalue from table1 `_()|; !y
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11、说明:几个高级查询运算词 e?7y$H-
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A: UNION 运算符 z }Lf]w?
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。 "8p<NsU
B: EXCEPT 运算符 >Hu3Guik]
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。 B)*1[Jf{4
C: INTERSECT 运算符 Quwq_.DU
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。 J`4V\D}n
注:使用运算词的几个查询结果行必须是一致的。 ?bH`
12、说明:使用外连接 bE,#,
A、left outer join: :N!s@6
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。 =Fc}T%
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 q[Tl#*P?y
B:right outer join: :-_"[:t 5Z
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。 -_xTs(;|8
C:full outer join: SP\s{,'F-b
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。 |No9eZ8>.
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二、提升 DUSQh+C
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ? o&goiM
法一:select * into b from a where 1<>1 v^J']p
法二:select top 0 * into b from a (}5};v
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) mPF<2:)wv
insert into b(a, b, c) select d,e,f from b; yIf^vx_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) i[4!% FxB
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {Hie%2V
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. r $[{sW
4、说明:子查询(表名1:a 表名2:b) iGSF5S
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Es- =0gpK
5、说明:显示文章、提交人和最后回复时间 ?E,-P!&R
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Scug
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6、说明:外连接查询(表名1:a 表名2:b) 3&I3ViAH
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c T_qM@/f
7、说明:在线视图查询(表名1:a ) ]4/C19Fe!
select * from (SELECT a,b,c FROM a) T where t.a > 1; SQ*%d.1
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 c'XSs
select * from table1 where time between time1 and time2 xU2i&il^!
select a,b,c, from table1 where a not between 数值1 and 数值2 .+mP#<mAg
9、说明:in 的使用方法 odDVdVx0
select * from table1 where a [not] in ('值1','值2','值4','值6') 8>G5VhCm~o
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ex#-,;T
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <`WDNi$Y
11、说明:四表联查问题: ^ ;K"Y'f$
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 ..... >(_2'c*[w
12、说明:日程安排提前五分钟提醒 +xAD;A4
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &lID6{7 9Z
13、说明:一条sql 语句搞定数据库分页 g##<d(e!}
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 nXk9
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14、说明:前10条记录 ~]24">VZf
select top 10 * form table1 where 范围 /eT9W[a
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.) 39m8iI%w[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) vTo+jQs^
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 bxPJ5oT
(select a from tableA ) except (select a from tableB) except (select a from tableC) A>,kmU5
17、说明:随机取出10条数据 3kh!dL3D
select top 10 * from tablename order by newid() k%8kt4\wn6
18、说明:随机选择记录 M;W&#Fz%
select newid() 03AQB;.
19、说明:删除重复记录 Xq_hC"s
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2s=zT5
20、说明:列出数据库里所有的表名 GDs/U1[*
select name from sysobjects where type='U' r"7PSJ
21、说明:列出表里的所有的 tJ*/5k
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select name from syscolumns where id=object_id('TableName') QE pCU)
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。 XZQ-Ig18
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 m^zD']
显示结果: ;pS+S0U
type vender pcs oB @)!'
电脑 A 1 m;nH
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电脑 A 1 9ei<ou_s
光盘 B 2 1;?w#/&t
光盘 A 2 VU6+"2+'2
手机 B 3 }8ESp3~e_
手机 C 3 _+)n}Se
23、说明:初始化表table1 bl^pMt1fv
TRUNCATE TABLE table1 iaQfxQP1w%
24、说明:选择从10到15的记录 EiP N44(
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]T(qk
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三、技巧 ?)[=>Kp
1、1=1,1=2的使用,在SQL语句组合时用的较多 Sj:c {jyJd
"where 1=1" 是表示选择全部 "where 1=2"全部不选, GY5JPl
如: xOr"3;^
if @strWhere !='' *>!-t
begin 8Ht=B,7T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere J*zQ8\f=}
end uhv_'Q
else 5!wjYQt3
begin cmYzS6f,7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' VD $PoP
end gv&Hu$ca
我们可以直接写成 )Jw$&%/{1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere oLtzPC
2、收缩数据库 xT( pB-R
--重建索引 /XA*:8~!
DBCC REINDEX fh66Gn,
DBCC INDEXDEFRAG Gm> =s
--收缩数据和日志 I~E&::,
DBCC SHRINKDB |Om9(xT
DBCC SHRINKFILE z_#HJ}R=
3、压缩数据库 X{[$4\di{
dbcc shrinkdatabase(dbname) ug'^$geM
4、转移数据库给新用户以已存在用户权限 9
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exec sp_change_users_login 'update_one','newname','oldname' -<AGCiLz
go dj4a)p|YN
5、检查备份集 @HE?G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' BlM(Q/z
6、修复数据库 U]B-B+-
ALTER DATABASE [dvbbs] SET SINGLE_USER ar S@l<79
GO 5E 9R+N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Bk@EQdn
GO :c Er{U8
ALTER DATABASE [dvbbs] SET MULTI_USER ?%lfbZ
GO Qs?p)3qp
7、日志清除 pAaNWm
SET NOCOUNT ON ooCfr?E
DECLARE @LogicalFileName sysname, ~ 588md :
@MaxMinutes INT, +.rE|)BPy
@NewSize INT -G#m'W&
USE tablename -- 要操作的数据库名 Eg2SC? 5
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {lUaN0O:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bYX.4(R
@NewSize = 1 -- 你想设定的日志文件的大小(M) <u1`o`|-
-- Setup / initialize ]3Ibl^J
DECLARE @OriginalSize int |oePB<N
SELECT @OriginalSize = size \@T;/Pj{[
FROM sysfiles sPl3JP&s
WHERE name = @LogicalFileName )cL`$h4DD
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8A/rkoht*
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ^4p$@5zH
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' " YOl6n
FROM sysfiles H(O|y2
WHERE name = @LogicalFileName -i_XP]b&
CREATE TABLE DummyTrans jLY$P<u?%P
(DummyColumn char (8000) not null) )c 79&S
DECLARE @Counter INT, yMmUOIxk\
@StartTime DATETIME, DMSC(Sz
@TruncLog VARCHAR(255) D'^%Q_;u
SELECT @StartTime = GETDATE(), b.8T<@a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0zsmZ]b5E
DBCC SHRINKFILE (@LogicalFileName, @NewSize) O%aHQL%Sz
EXEC (@TruncLog) h2= wC.
-- Wrap the log if necessary. (yeWArQ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ]US!3R^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) AM#s2.@
AND (@OriginalSize * 8 /1024) > @NewSize +tG'
BEGIN -- Outer loop. \.GA"_y
SELECT @Counter = 0 SL\15`[{
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) fP8bWZ{
BEGIN -- update bweAmSs
INSERT DummyTrans VALUES ('Fill Log') 5d# 73)x$
DELETE DummyTrans $:UD #eh0?
SELECT @Counter = @Counter + 1 JW=q'ibR
END pX$X8z%
EXEC (@TruncLog) F}@]Lq+
END )jjaY1E
SELECT 'Final Size of ' + db_name() + ' LOG is ' + H;DjM;be
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7h:EU7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^gY'^2bzxu
FROM sysfiles 5`i+aH(
WHERE name = @LogicalFileName EY
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DROP TABLE DummyTrans 'z=d&K
SET NOCOUNT OFF 6(Ntt
8、说明:更改某个表 nQg_1+
exec sp_changeobjectowner 'tablename','dbo' LY#V)f
9、存储更改全部表 _?K,Jc8j.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch d69dC*>
@OldOwner as NVARCHAR(128), M6V^ur 1
@NewOwner as NVARCHAR(128) dYlVJ_0Zr
AS dl`{:ZR S
DECLARE @Name as NVARCHAR(128) 9A|9:OdG1
DECLARE @Owner as NVARCHAR(128) )t:8;;W@Ir
DECLARE @OwnerName as NVARCHAR(128) 2r]o>X
DECLARE curObject CURSOR FOR Ysw&J}6e
select 'Name' = name, ~at:\h4:
'Owner' = user_name(uid) T&:~=
from sysobjects Um*&S.y
where user_name(uid)=@OldOwner S0LaQ<9.
order by name THgEHR0,}[
OPEN curObject uU-1;m#N?
FETCH NEXT FROM curObject INTO @Name, @Owner afu!.}4Ct
WHILE(@@FETCH_STATUS=0) ,Vof<,x0
BEGIN '!`]Zc
if @Owner=@OldOwner qd~9uo&[Ig
begin EN8xn9M?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) D^U?!S&4~
exec sp_changeobjectowner @OwnerName, @NewOwner M7-2;MZ
end _kBx2>qQ
-- select @name,@NewOwner,@OldOwner ?N@[R];
FETCH NEXT FROM curObject INTO @Name, @Owner zH#urF6<
END 5{v uN)K3
close curObject 0h{&k7T<7
deallocate curObject $ERiBALN:
GO |8)\8b|VuC
10、SQL SERVER中直接循环写入数据 IP)%y%ycw
declare @i int {K:]dO
set @i=1 2i NZz
while @i<30 K `A8N
begin qG]0z_dPE~
insert into test (userid) values(@i) ]*Kv[%r07c
set @i=@i+1 O.8k [Ht
end 1?Tj
小记存储过程中经常用到的本周,本月,本年函数 8]bLp
Dateadd(wk,datediff(wk,0,getdate()),-1) wLvM<p7OX
Dateadd(wk,datediff(wk,0,getdate()),6) IABF_GwF
Dateadd(mm,datediff(mm,0,getdate()),0) CT'#~~QB
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) XK)0Mt\
Dateadd(yy,datediff(yy,0,getdate()),0) gg Nvm
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Yn0iu$;n
上面的SQL代码只是一个时间段 :-(qqC:
Dateadd(wk,datediff(wk,0,getdate()),-1) %c8@
Dateadd(wk,datediff(wk,0,getdate()),6) EW+QVu@
就是表示本周时间段. >t%@)]*N
下面的SQL的条件部分,就是查询时间段在本周范围内的: [ A 7{}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~)6EH`-
而在存储过程中 @18}'k
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) l 3 jlKB
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ,3!4
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