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。 hrtz>qN
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一、基础 5LB{b]w7m
1、说明:创建数据库 Jn^b}bk t
CREATE DATABASE database-name Hc=QSP
2、说明:删除数据库 ghWWJx9
drop database dbname t+}wTis
3、说明:备份sql server Bp_R"DS7A
--- 创建 备份数据的 device 7]xDMu'^&f
USE master i?Pnyi
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^l|b>z"0ao
--- 开始 备份 C= V2Y_j
BACKUP DATABASE pubs TO testBack 1Vdi5;dn
4、说明:创建新表 F'b%D
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ,#UZp\zZ*
根据已有的表创建新表: Jr( =Y@Z'
A:create table tab_new like tab_old (使用旧表创建新表) '{UKO7
B:create table tab_new as select col1,col2... from tab_old definition only ] re=8s6
5、说明:删除新表 E#!!tH`lgg
drop table tabname _ Lb"yug
6、说明:增加一个列 fE+zA)KX
Alter table tabname add column col type 7n6g;8xE
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,G_&5|f%
7、说明:添加主键: Alter table tabname add primary key(col) hp)^s7H
说明:删除主键: Alter table tabname drop primary key(col) gr SF}y!3
8、说明:创建索引:create [unique] index idxname on tabname(col....) GM0Q@`d
删除索引:drop index idxname J _;H
注:索引是不可更改的,想更改必须删除重新建。 {?eUAB<
9、说明:创建视图:create view viewname as select statement <kdlXS>J.
删除视图:drop view viewname 3}<U'%sd
10、说明:几个简单的基本的sql语句 zk
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选择:select * from table1 where 范围 N=BG0t$
插入:insert into table1(field1,field2) values(value1,value2) bO2?DszT5
删除:delete from table1 where 范围 *$ g!/,
更新:update table1 set field1=value1 where 范围 Z;Hkx1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! M/quswn1
排序:select * from table1 order by field1,field2 [desc] ,< x/
总数:select count as totalcount from table1 l P3|h*
求和:select sum(field1) as sumvalue from table1 Si>38vCJ*
平均:select avg(field1) as avgvalue from table1 )Q'E^[Ua
最大:select max(field1) as maxvalue from table1 g w([08
最小:select min(field1) as minvalue from table1 zo(#tQ-'m
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11、说明:几个高级查询运算词 FKTF?4+\U
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A: UNION 运算符 0cq@lT6
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。 .how@>:P+
B: EXCEPT 运算符 93HVx#
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。 (QiA5!wg
C: INTERSECT 运算符 +gX,r$bX
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。 L'e^D|
注:使用运算词的几个查询结果行必须是一致的。 n" Ie>
12、说明:使用外连接 +:.Jl:fx4
A、left outer join: =EP`,zqn$9
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 985F(r
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c HE,L8S
B:right outer join: K:a8}w>Up
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 sQa;l]O:NC
C:full outer join: 2bNOn%!
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Cf=H~&`Z
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二、提升 V:kRr cX
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .J)TIc__|A
法一:select * into b from a where 1<>1 T;/GHC`{Y
法二:select top 0 * into b from a sllT1%?
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "l56?@- x
insert into b(a, b, c) select d,e,f from b; `N *:,8j
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) A)&FcMO*z
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 0N,<v7PX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. s1D<R,J|H
4、说明:子查询(表名1:a 表名2:b) = {O ~
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) :Z//
5、说明:显示文章、提交人和最后回复时间 H2s:M
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _J
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6、说明:外连接查询(表名1:a 表名2:b) h=7q;-@7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c KS$t
7、说明:在线视图查询(表名1:a ) _6NUtU
select * from (SELECT a,b,c FROM a) T where t.a > 1; gF{ehU%
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 ^3$l!>me
select * from table1 where time between time1 and time2 qH}8TC
select a,b,c, from table1 where a not between 数值1 and 数值2 lGd'_~'=
9、说明:in 的使用方法 1ML L
select * from table1 where a [not] in ('值1','值2','值4','值6') OyZR&,q
10、说明:两张关联表,删除主表中已经在副表中没有的信息 JN0h3nZ_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +
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11、说明:四表联查问题: tK%ie\
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 ..... N)X Tmh2v|
12、说明:日程安排提前五分钟提醒 '47
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !g|O.mt
13、说明:一条sql 语句搞定数据库分页 !DZ=`a?y
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 UX)GA[WI
14、说明:前10条记录 _Je4&KU
select top 10 * form table1 where 范围 }%_|k^t
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.) o+a=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~rb0G*R>
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 P8d
(select a from tableA ) except (select a from tableB) except (select a from tableC) +~^S'6yB
17、说明:随机取出10条数据 n[3z_QI
select top 10 * from tablename order by newid() ,9P-<P
18、说明:随机选择记录 U**8^:*y#:
select newid() "6f`hy
19、说明:删除重复记录 i HD!v7d7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2LwJ%!
20、说明:列出数据库里所有的表名 ]@&X*~c^Z
select name from sysobjects where type='U' h6h6B.\Ld
21、说明:列出表里的所有的 Ei4^__g\'
select name from syscolumns where id=object_id('TableName') <7^|@L
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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。 %Rk|B`ST
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 $Ll9ak}
显示结果: =l`)b
type vender pcs NI V}hf YF
电脑 A 1 #fuUAbU0X
电脑 A 1 v"G1vSx)BT
光盘 B 2 iq; |
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光盘 A 2 75# 8P?i
手机 B 3 g&$=Y7G
手机 C 3 6@N,'a8r
23、说明:初始化表table1 8Qg10Yjy
TRUNCATE TABLE table1 ]cp b;UfM
24、说明:选择从10到15的记录 ,;g%/6X
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc P@7>R7gS
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三、技巧 s@\3|e5g
1、1=1,1=2的使用,在SQL语句组合时用的较多 >. |({;n9
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `|'w]rj:"+
如: `nPdZ.
if @strWhere !='' C`.YOkpj
begin nrl?<4_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,h*gd^i
end N*Aw-\Bk
else AFAg3/
begin yYCS-rF>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 'UhoKb_p
end 8M5)fDu*?
我们可以直接写成 $C[z]}iOi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere r[L.TX3Ah=
2、收缩数据库 9Dx~!(
--重建索引 P#O"{+`
DBCC REINDEX cE\w6uBR1
DBCC INDEXDEFRAG [3Q0KCZ0(
--收缩数据和日志 t#NPbLZ
DBCC SHRINKDB FZ-Wgh
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DBCC SHRINKFILE (p{X.X+
3、压缩数据库 cIU2 qFn[
dbcc shrinkdatabase(dbname) ,?GwA@~$k:
4、转移数据库给新用户以已存在用户权限 j
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exec sp_change_users_login 'update_one','newname','oldname' ]es|%j 2
go dSGdK
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5、检查备份集 ]\39#
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' #/G!nN #
6、修复数据库 '.|}
ALTER DATABASE [dvbbs] SET SINGLE_USER 1w>[
GO vpu#!(N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ik:G5m<ta
GO `cGks
ALTER DATABASE [dvbbs] SET MULTI_USER I-#!mFl
GO u+)!C*ho
7、日志清除 mY 1l2
SET NOCOUNT ON =Vg~ VD
DECLARE @LogicalFileName sysname, yq~
@MaxMinutes INT, ?{J1&;j*
@NewSize INT .}dLqw
USE tablename -- 要操作的数据库名 j7P49{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~^F]t$rz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |O8e;v72g^
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0LQRQuh1
-- Setup / initialize a
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DECLARE @OriginalSize int } 9@rhW
SELECT @OriginalSize = size ^%\a,~
FROM sysfiles kepuh%KY[
WHERE name = @LogicalFileName ().C
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #/qcp|m
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + khX/xL
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 0}i
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FROM sysfiles lU1SN/'zx
WHERE name = @LogicalFileName e@hPb$7
CREATE TABLE DummyTrans >@N.jw>#T
(DummyColumn char (8000) not null) 1]}\h]*
DECLARE @Counter INT, !&U75FpN}:
@StartTime DATETIME, <$nPGz)}
@TruncLog VARCHAR(255) Q=Q+*oog
SELECT @StartTime = GETDATE(), d!I%AlV
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' `q}D#0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LW=qX%o{
EXEC (@TruncLog) =9&2udV1
-- Wrap the log if necessary. JQ+Mg&&Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 48p3m)5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) KDN#CU
AND (@OriginalSize * 8 /1024) > @NewSize L4iWR/&
BEGIN -- Outer loop. whI4@#
SELECT @Counter = 0 HVM%B{(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I(6%'s2
BEGIN -- update cC8$ oCR?
INSERT DummyTrans VALUES ('Fill Log') ihkZs3}
DELETE DummyTrans Gb^63.}
SELECT @Counter = @Counter + 1 i3 js'?7E
END ZRhk2DA#FF
EXEC (@TruncLog) )=)N9C Ry
END {tVA(&\<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + jnV#Q
;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Gr({30"8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q~qz^E\T
FROM sysfiles kV8R.Baf3
WHERE name = @LogicalFileName 3n2^;b/ ]
DROP TABLE DummyTrans Q}&'1J
SET NOCOUNT OFF S%RxYJ(
8、说明:更改某个表 b8a(.}8*
exec sp_changeobjectowner 'tablename','dbo' 6Emn@Mn=
9、存储更改全部表 uNf'Zeo
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Nr@,In|JS
@OldOwner as NVARCHAR(128), CX#d
@NewOwner as NVARCHAR(128) !d##q)D
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AS B~o3Z
DECLARE @Name as NVARCHAR(128) ^ iu)vED
DECLARE @Owner as NVARCHAR(128) 8z93ETv7`
DECLARE @OwnerName as NVARCHAR(128) -dMH>e0
DECLARE curObject CURSOR FOR CQ!D{o=
select 'Name' = name, nu^@}|UG
'Owner' = user_name(uid) 5]{rim
from sysobjects !jP[=
where user_name(uid)=@OldOwner /8Lb_QH{
order by name !UzE&CirV
OPEN curObject 7:~3B-Tb
FETCH NEXT FROM curObject INTO @Name, @Owner v0'z''KM!
WHILE(@@FETCH_STATUS=0) :{w3l O
BEGIN I>MLI=[Kg
if @Owner=@OldOwner r[E #JHw
begin ^3HSw ?a"
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Va[&~lA)
exec sp_changeobjectowner @OwnerName, @NewOwner 7gtaI3
end #W:.Fsq
-- select @name,@NewOwner,@OldOwner &'\-M6GW
FETCH NEXT FROM curObject INTO @Name, @Owner n_sV>$f-u
END aR6~r^jB
close curObject " "`z3-
deallocate curObject qA}l[:F+#
GO , wk}[MF
10、SQL SERVER中直接循环写入数据 dhLd2WSyH
declare @i int # wn>S<
set @i=1 i% 0qN
while @i<30 Ps!
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begin ca
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insert into test (userid) values(@i) ^cdbM
set @i=@i+1 YloE4PAY7
end E=.J*7
小记存储过程中经常用到的本周,本月,本年函数 +) 9=bB
Dateadd(wk,datediff(wk,0,getdate()),-1) 8hV4l'Pa72
Dateadd(wk,datediff(wk,0,getdate()),6) :|l0x a
Dateadd(mm,datediff(mm,0,getdate()),0) 1xxTI{'g[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) k8Dk;N
Dateadd(yy,datediff(yy,0,getdate()),0) T&dc)t`o
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ddYb=L+_b
上面的SQL代码只是一个时间段 B <Jxj
Dateadd(wk,datediff(wk,0,getdate()),-1) RCkmxO;b&
Dateadd(wk,datediff(wk,0,getdate()),6) __z/X"H
就是表示本周时间段. Y}vV.q
下面的SQL的条件部分,就是查询时间段在本周范围内的: `34+~;;Jh
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) af'ncZ@U
而在存储过程中 ]_>38f7h
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >U:-U"rA?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ;{m;CKHI