精妙SQL语句收集『转载』

上一篇 / 下一篇  2007-08-22 16:06:53 / 个人分类:SQL数据库


sK"|9l,LQ18755原文转至CSDN http://blog.csdn.net/chen8148/archive/2007/08/14/1741991.aspx
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A8}e\G9V+k18755精妙 SQL 语句收集
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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。
6c(Z$F4}4T#o+TQ.~'j/Q:C18755一、基础51Testing软件测试网3F-G(]5r ]PJ
1、说明:创建数据库
&g!K s$F(d_j'Q*E18755CREATE DATABASE database-name51Testing软件测试网9jDO0DX|
2、说明:删除数据库51Testing软件测试网o/["Rj@
drop database dbname
Z unx1ov fi}187553、说明:备份sql server51Testing软件测试网Rcv%z rs,E
--- 创建 备份数据的 device
M(R ])\ m!p^18755USE master51Testing软件测试网"VIq1|+n'wP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'51Testing软件测试网:UYST#U,b|.r
--- 开始 备份
VA3N4O%P^!wB18755BACKUP DATABASE pubs TO testBack
%^4l I g4vBv187554、说明:创建新表51Testing软件测试网9D$rId:mw F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
8Gk;^*x/BL"R18755根据已有的表创建新表:51Testing软件测试网4gz-P*~8`rY
A:create table tab_new like tab_old (使用旧表创建新表)
+V7o"lF7JMO;L:u18755B:create table tab_new as select col1,col2... from tab_old definition only51Testing软件测试网Xwk;O(Xb&g0T3M
5、说明:删除新表51Testing软件测试网Ax(n_xvk d
drop table tabname51Testing软件测试网"S{ y3n vE
6、说明:增加一个列
a j @8AS,u/Xk18755Alter table tabname add column col type
zhBo7^([#j,q A18755注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。51Testing软件测试网 pZ}QZMS*E
7、说明:添加主键: Alter table tabname add primary key(col)51Testing软件测试网b.r+k3vwXU
说明:删除主键: Alter table tabname drop primary key(col)51Testing软件测试网?O/Rrh X
8、说明:创建索引:create [unique] index idxname on tabname(col....)51Testing软件测试网#[[T}#m$B?Va Y
删除索引:drop index idxname
Bu ebR)y18755注:索引是不可更改的,想更改必须删除重新建。
}W/@-ppa'i9\187559、说明:创建视图:create view viewname as select statement
af ~z f18755删除视图:drop view viewname
Bx&y5nb w(Y%h1875510、说明:几个简单的基本的sql语句
ce l#VY pc I@ E/|18755选择:select * from table1 where 范围51Testing软件测试网3{0]:S@6YM$V
插入:insert into table1(field1,field2) values(value1,value2)51Testing软件测试网Jx D]5w] J
删除:delete from table1 where 范围
B @6N&Fl-N3f9{)D18755更新:update table1 set field1=value1 where 范围
!j,Z P_ m2V,[h18755查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
4vG,F:e3|5I$P"T N18755排序:select * from table1 order by field1,field2 [desc]51Testing软件测试网;QEMbY0m9GvZ:|-m.e
总数:select count as totalcount from table1
|!G z\9` c H'b18755求和:select sum(field1) as sumvalue from table1
#C%MLcaQ_b18755平均:select avg(field1) as avgvalue from table151Testing软件测试网9[MI6f~&D:pH&}[)g
最大:select max(field1) as maxvalue from table151Testing软件测试网U0T9jDL'W8x m6D*F
最小:select min(field1) as minvalue from table151Testing软件测试网$m-k"uhp#m/xuDr*F
11、说明:几个高级查询运算词51Testing软件测试网:Ju9A0_#Nl0SVz
A: UNION 运算符
Em&f-~@:CQ&@18755UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。51Testing软件测试网 w.S)ioN8X
B: EXCEPT 运算符51Testing软件测试网]e` X-mW
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。
:t#e:I/WhWo(he18755C: INTERSECT 运算符
h.q)[b!a.k@18755INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。
(G(x[Be4\ eMu5X Q18755注:使用运算词的几个查询结果行必须是一致的。51Testing软件测试网2lO#q k5w"X:@
12、说明:使用外连接51Testing软件测试网j|#Ba5d0{
A、left outer join:
!Vs1TpAzlOA {\18755左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。
ix va!Z'c18755SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
Z_Ex ~ P9D18755B:right outer join:51Testing软件测试网-B~"RZUSGPju
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。51Testing软件测试网 lY'xyTeb
C:full outer join:51Testing软件测试网Ntol%f
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。
:R-yc)H QWN18755二、提升
wjt%\;IP-D kSLO187551、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)51Testing软件测试网}^#Ng9L^#M
法一:select * into b from a where 1<>151Testing软件测试网A'Y$w.U/E v Y
法二:select top 0 * into b from a51Testing软件测试网/`.G5}:W fC"Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
_#aY1]3Q18755insert into b(a, b, c) select d,e,f from b;
.IP.KyKZ R-o187553、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)
6jHFdU(Qx18755insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件51Testing软件测试网m!]I P(_M
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..51Testing软件测试网G$qn5k vO5q
4、说明:子查询(表名1:a 表名2:b)51Testing软件测试网#?!rc+aA!m/eJw!I
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3)51Testing软件测试网n2Y8W ^o_6jH
5、说明:显示文章、提交人和最后回复时间51Testing软件测试网-NvM9WI(T,@
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b51Testing软件测试网w,_PzR _fH
6、说明:外连接查询(表名1:a 表名2:b)51Testing软件测试网Rp|J({ @a*?{5A
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c51Testing软件测试网XR?R;s!WA
7、说明:在线视图查询(表名1:a )
g,PH}(F,xK5tI-s18755select * from (SELECT a,b,c FROM a) T where t.a > 1;
#z;B R0AMlRm6l9s6h187558、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括
o |Rh{ _18755select * from table1 where time between time1 and time2
4{h,yCm%E1Q18755select a,b,c, from table1 where a not between 数值1 and 数值251Testing软件测试网c({P!t0Q.gQ
9、说明:in 的使用方法
U f:b#n4t%f {$f9^;k18755select * from table1 where a [not] in ('值1','值2','值4','值6')
^.d9Z\*{1875510、说明:两张关联表,删除主表中已经在副表中没有的信息
HR,wruw c5nY'|18755delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )51Testing软件测试网+pvy'O._X1[f|
11、说明:四表联查问题:51Testing软件测试网Ki["s$bu @ Q9v1E;}
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
,{ n2^/Z9a1X1875512、说明:日程安排提前五分钟提醒
ob2O,y(G#y,D8V18755SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>551Testing软件测试网+SjL1j&X)p/v7R^
13、说明:一条sql 语句搞定数据库分页
4Q2va-O1F4D_18755select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段51Testing软件测试网Fdj!U M6ZZ ?
14、说明:前10条记录
~9KPx)zU v18755select top 10 * form table1 where 范围
!QH7ov H8h nQ1875515、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
)ly2n4n$D'vq]X18755select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
c kO/P?X l1mi1875516、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
2GK5Q?e)UR18755(select a from tableA ) except (select a from tableB) except (select a from tableC)
Dc g U#_1875517、说明:随机取出10条数据
d tu3r.H7fS18755select top 10 * from tablename order by newid()
K t U5x {sO^o1875518、说明:随机选择记录
s;Pl&u_kd*ZEu18755select newid()
ycm0c7W F2}s1875519、说明:删除重复记录51Testing软件测试网+b1i,x].@kek
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)51Testing软件测试网Z%Dl J'a9n/j
20、说明:列出数据库里所有的表名
ZO \ K.L0F18755select name from sysobjects where type='U'51Testing软件测试网rR3p8F)O
21、说明:列出表里的所有的51Testing软件测试网3N7vu(P.{N7H
select name from syscolumns where id=object_id('TableName')51Testing软件测试网 r |A&T{3hE4E
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。
3Z S4n,EV*_X18755select 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
lk]GxSh18755显示结果:
kVUW+NZW:YB3}18755type vender pcs51Testing软件测试网,Q/JZ+^e{/Kc"L
电脑 A 151Testing软件测试网 D6x-PqErp6G
电脑 A 1
LlU|,g%G18755光盘 B 2
3D$S:tM4`C0M18755光盘 A 2
b-ot'I(_XD18755手机 B 351Testing软件测试网-C;UENl4P'U Q
手机 C 3
T_#c4E3b `$cf8w,Kkw1875523、说明:初始化表table151Testing软件测试网"FE hi"\i(j8n2\
TRUNCATE TABLE table1
VuG9z-a\9D1875524、说明:选择从10到15的记录51Testing软件测试网[ }8tLy NCj`!w5KL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc
6ry {!\,Lk18755三、技巧
H)O:t(a_WdFb187551、1=1,1=2的使用,在SQL语句组合时用的较多
$gV+]Eiq1D5hz18755"where 1=1" 是表示选择全部   "where 1=2"全部不选,
/Gix"lXU4p h18755如:
$[ b(Nr e ^.d DuJ18755if @strWhere !=''
n&d%{1@6JUo+]8~+}18755begin
J a\!bON$x Z18755set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere
)[+I6@uRQ G G6a18755end
;o h5O;lD)V18755else51Testing软件测试网3~3DqP8XdK2U
begin
p.o4\0U9YK&W%l-A18755set @strSQL = 'select count(*) as Total from [' + @tblName + ']'51Testing软件测试网-x6?-`iX0cp?:O G
end51Testing软件测试网Q!Jg2Pi6^Ja
我们可以直接写成
EJ#}`m[r18755set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere
(k&OeG"V1@b3Q/G187552、收缩数据库
J/gZ r8D+e:ErCe18755--重建索引
kt&V ql3U0[0i*c9]| e18755DBCC REINDEX
AbE O9XO18755DBCC INDEXDEFRAG
K_R3vBPF18755--收缩数据和日志
X:DUed;H18755DBCC SHRINKDB
6qD}U ~18755DBCC SHRINKFILE51Testing软件测试网~ZrFYW'R9X7^4X
3、压缩数据库
Y8B+z5yE*iT@.D_18755dbcc shrinkdatabase(dbname)51Testing软件测试网w1j5[6@6U8z
4、转移数据库给新用户以已存在用户权限51Testing软件测试网 Ix)ur8G/Zz#E R
exec sp_change_users_login 'update_one','newname','oldname'51Testing软件测试网#H#[4I;qC ^6Qo(wy-?-L
go
%@$w @ O6JH'B187555、检查备份集
"`n^ M @?*N t.[h18755RESTORE VERIFYONLY from disk='E:\dvbbs.bak'51Testing软件测试网!m;riax;}?
6、修复数据库51Testing软件测试网%[j-? zH
ALTER DATABASE [dvbbs] SET SINGLE_USER
-|W {9v/[5f B18755GO51Testing软件测试网I,K9^5` W&yu
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK51Testing软件测试网,CPBQm8f5Z[
GO
1]%T/U&?(z;@$_18755ALTER DATABASE [dvbbs] SET MULTI_USER
/y&y7GJ7@rZ:sHZ2|18755GO
N;H4V[(|\}187557、日志清除
#tZ(S^;X^ ZX [9a5^18755SET NOCOUNT ON51Testing软件测试网6YD+Fq[
DECLARE @LogicalFileName sysname,51Testing软件测试网j*Gx2CdDdNV
        @MaxMinutes INT,51Testing软件测试网K'g'z@|
        @NewSize INT

USE     tablename             -- 要操作的数据库名
}3|H Qr!WA18755SELECT  @LogicalFileName = 'tablename_log',  -- 日志文件名51Testing软件测试网UXZ3G-z
@MaxMinutes = 10,               -- Limit on time allowed to wrap log.
r9N,t yv&yZ18755        @NewSize = 1                  -- 你想设定的日志文件的大小(M)
Y\G4r~].][18755-- Setup / initialize51Testing软件测试网`Bus%j[sWE
DECLARE @OriginalSize int
+B*l{0v)V3Nk{&b F18755SELECT @OriginalSize = size
_Rm'NH'^HNT18755  FROM sysfiles
+})UeP/EZ18755  WHERE name = @LogicalFileName51Testing软件测试网%n H J3U VN9P
SELECT 'Original Size of ' + db_name() + ' LOG is ' +51Testing软件测试网-?Rb(^n$aur
        CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
1N9d*Hf$E\$~&q_q4i18755        CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
:~x!q3|hG18755  FROM sysfiles
-}s,k!hq"xO3b{18755  WHERE name = @LogicalFileName
5p SE[6\-Od,J8r18755CREATE TABLE DummyTrans
!s[*wIE:l Tggu18755  (DummyColumn char (8000) not null)

DECLARE @Counter   INT,51Testing软件测试网t:j%k+R"z p P8}@
        @StartTime DATETIME,51Testing软件测试网}.B"Z9W`y b+n
        @TruncLog  VARCHAR(255)51Testing软件测试网h@X{(A
SELECT  @StartTime = GETDATE(),
#M eK{ BJ18755        @TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'51Testing软件测试网'P2a AA[$qb;Ak
DBCC SHRINKFILE (@LogicalFileName, @NewSize)51Testing软件测试网WLI0C;w(Z*tO
EXEC (@TruncLog)51Testing软件测试网(U/`1D ]/\1WK&S
-- Wrap the log if necessary.51Testing软件测试网(j e|D7Y$L4Z$LZ
WHILE     @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
;Sq@ ].o18755      AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 
/O_~M'y ^18755      AND (@OriginalSize * 8 /1024) > @NewSize 
d2}/Z:C)g0_0L18755  BEGIN -- Outer loop.51Testing软件测试网O"] U%l mW ML8__
    SELECT @Counter = 0
I0W ev7W18755    WHILE  ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
mL"K5Y$x WW9|18755      BEGIN -- update51Testing软件测试网C2O J:~}
        INSERT DummyTrans VALUES ('Fill Log') 51Testing软件测试网}Sk9V!TN+G
        DELETE DummyTrans
:l)Q~qG1C"wm2E18755        SELECT @Counter = @Counter + 151Testing软件测试网@T,xg4\
      END  51Testing软件测试网2q Ieb J g
    EXEC (@TruncLog) 51Testing软件测试网h-x z&d*tPa
  END  51Testing软件测试网6^Ko;XmS3qM
SELECT 'Final Size of ' + db_name() + ' LOG is ' +
:A8|^2Hs+Q7x'Q}18755        CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
-?D-Y-h8D18755        CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
1[H _Zy$^s9xNP18755  FROM sysfiles
sN*V`/KN18755  WHERE name = @LogicalFileName
o*]+e ^vg F18755DROP TABLE DummyTrans
_W"{ _,QjH6l\(f18755SET NOCOUNT OFF
Dl2{/Mj(n187558、说明:更改某个表51Testing软件测试网.G0aU2j&w9[@ Z$o7{
exec sp_changeobjectowner 'tablename','dbo'51Testing软件测试网,_ } aVBR
9、存储更改全部表
L,vE9dv0T9`,^2]O18755CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch51Testing软件测试网D%CuV(a[j s
 @OldOwner as NVARCHAR(128),
$Un8l(L\b&O18755 @NewOwner as NVARCHAR(128)51Testing软件测试网o9m Wy&]/yD
AS
0yVvP8U)U18755DECLARE @Name   as NVARCHAR(128)
w!GTK/~)X18755DECLARE @Owner  as NVARCHAR(128)51Testing软件测试网vU9d5t'_X)h2v
DECLARE @OwnerName  as NVARCHAR(128)51Testing软件测试网 W7F3ld8Z:W5O1mo
DECLARE curObject CURSOR FOR
I(Gp1F-bs18755 select 'Name'   = name,
*jJ{+e!KW j4iUsuA18755  'Owner'   = user_name(uid)
2i(T!] Z4ls18755 from sysobjects
uGS ?g*b3p#L T18755 where user_name(uid)=@OldOwner51Testing软件测试网.C5@6\9t)`3s
 order by name
IG-vT+|s18755OPEN  curObject
AV!~6T4}-iY R2j*gO%Q18755FETCH NEXT FROM curObject INTO @Name, @Owner
F"z}Pd18755WHILE(@@FETCH_STATUS=0)
x,A G"vp ^0?&|-]18755BEGIN    
O&C \g*v t,F5L18755 if @Owner=@OldOwner
0X+O?c,^18755 begin51Testing软件测试网 u&d xc&y mG
  set @OwnerName = @OldOwner + '.' + rtrim(@Name)51Testing软件测试网lI6H,G!YB;l
  exec sp_changeobjectowner @OwnerName, @NewOwner51Testing软件测试网~+WH.X?e i
 end51Testing软件测试网^2p xpcWQ
-- select @name,@NewOwner,@OldOwner
i:P0GV/G^%h0d,o1y18755 FETCH NEXT FROM curObject INTO @Name, @Owner
w5[7\$l{_D18755END51Testing软件测试网mcxr|GW
close curObject51Testing软件测试网!Q-Rj DtK c xFC
deallocate curObject51Testing软件测试网,F+JzlN-bt6u
GO

10、SQL SERVER中直接循环写入数据51Testing软件测试网 |/k B.V6h%QNv
declare @i int51Testing软件测试网z3Z$Y'Gxo9F
set @i=1
C o)x/D uq3C18755while @i<3051Testing软件测试网/ta8j~7W4|F2x
begin51Testing软件测试网6C DXv7I/\q5nP`
   insert intotest(userid) values(@i)
7jN"eX6P18755   set @i=@i+1
*~[-~6BXAV Zz18755end51Testing软件测试网T\2E]*Y*F
小记存储过程中经常用到的本周,本月,本年函数51Testing软件测试网?iDj2G6n'zs2Q
Dateadd(wk,datediff(wk,0,getdate()),-1)51Testing软件测试网9gTX&i3W|]c"C'o ^S
Dateadd(wk,datediff(wk,0,getdate()),6)
#G,mhX _*ZV2I18755Dateadd(mm,datediff(mm,0,getdate()),0)
6bHzx bT~;DA@18755Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))51Testing软件测试网F.HZd ay
Dateadd(yy,datediff(yy,0,getdate()),0)
o MC(BG:}$]18755Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))51Testing软件测试网8cSJ+M/^T
上面的SQL代码只是一个时间段
vJ"Q/bIw2k(l18755Dateadd(wk,datediff(wk,0,getdate()),-1)
NbuDFybv18755Dateadd(wk,datediff(wk,0,getdate()),6)
Z]#cV;{ av+c9\18755就是表示本周时间段.
o!rVyl(_)PYJ18755下面的SQL的条件部分,就是查询时间段在本周范围内的:
`)]Q.Y9IEP18755Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6)51Testing软件测试网|w U Hlx4S3P
而在存储过程中51Testing软件测试网 B"md'^0q0[ V r
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
X%_8I+gH18755select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)


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