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。 7U&5^s
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一、基础 Hde]DK,d
1、说明:创建数据库 Po'-z<}wS
CREATE DATABASE database-name >_&~!Y.Z=
2、说明:删除数据库 J 5Wz4`'
drop database dbname
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3、说明:备份sql server y>>vGU;
--- 创建 备份数据的 device UaH26fWs
USE master lTxY6vi
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @c6"RHG9
--- 开始 备份 c"sj)-_
BACKUP DATABASE pubs TO testBack P#w}3^
4、说明:创建新表 ub[""M?
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) <\E"clZI
根据已有的表创建新表: +8Of-ZUx
A:create table tab_new like tab_old (使用旧表创建新表) m5X3{[a:
B:create table tab_new as select col1,col2... from tab_old definition only u+I3IdU3
5、说明:删除新表 wy,Jw3
drop table tabname wCV>F-
6、说明:增加一个列 5dg-d\6S
Alter table tabname add column col type UN-T^
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。 B jH ~Ml2
7、说明:添加主键: Alter table tabname add primary key(col) =Dh$yC-Zr
说明:删除主键: Alter table tabname drop primary key(col) oP+kAV#]
8、说明:创建索引:create [unique] index idxname on tabname(col....) 44'=;/
删除索引:drop index idxname n33JTqX
注:索引是不可更改的,想更改必须删除重新建。 1y},9ym
9、说明:创建视图:create view viewname as select statement [B}1z
删除视图:drop view viewname 7k'=F m6za
10、说明:几个简单的基本的sql语句 [SCw<<l<
选择:select * from table1 where 范围 hO^&0?
插入:insert into table1(field1,field2) values(value1,value2) hZp=BM"bJ
删除:delete from table1 where 范围 8]sTX9
更新:update table1 set field1=value1 where 范围 'q{PtYr
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! xIS\4]F?r
排序:select * from table1 order by field1,field2 [desc] IUluJ.sXIf
总数:select count as totalcount from table1 //#xK D
求和:select sum(field1) as sumvalue from table1 H @_eFlT t
平均:select avg(field1) as avgvalue from table1 kb/|;!
最大:select max(field1) as maxvalue from table1 @`w'
最小:select min(field1) as minvalue from table1 aEcktg6h
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11、说明:几个高级查询运算词 RnMB Gxa
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A: UNION 运算符 2(c<U6#C'l
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。 c'4>D,?1
B: EXCEPT 运算符 JK@izI
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。 |HaU3E*R
C: INTERSECT 运算符 aDm-X r
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。 u~'m7
注:使用运算词的几个查询结果行必须是一致的。 tU+@1~
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12、说明:使用外连接 2"pE&QNd
A、left outer join: xB?S#5G}
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。 JIyBhFI
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 ddUjs8VvJ
B:right outer join: `U{o:
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。 {toyQ)C7
C:full outer join: qR [}EX&3
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。 =q_&*'
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二、提升 p{A}p9sjx
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) p{mxk)A
法一:select * into b from a where 1<>1 ](B&l{V
法二:select top 0 * into b from a uznoyj6g
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .jU|gf:x
insert into b(a, b, c) select d,e,f from b; v YRt2({}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) +zFV~]b
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 xFsB?d
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. kWZ/ej
4、说明:子查询(表名1:a 表名2:b) jOoIF/So
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) j33P~H~
5、说明:显示文章、提交人和最后回复时间 *=-__|t
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b WmT}t
6、说明:外连接查询(表名1:a 表名2:b) MZUF! B
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c pm'@2dT
7、说明:在线视图查询(表名1:a ) QOkE\ro
select * from (SELECT a,b,c FROM a) T where t.a > 1; l|@/?GaH
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 GibggOj2Q,
select * from table1 where time between time1 and time2 m[g< K
select a,b,c, from table1 where a not between 数值1 and 数值2 |QAeQWP+1
9、说明:in 的使用方法 ,z?<7F1q=
select * from table1 where a [not] in ('值1','值2','值4','值6') 2a._?(k_y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9B!im\]O
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4i+PiD:H
11、说明:四表联查问题: 4b3 F9
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 ..... W2r6jm!
12、说明:日程安排提前五分钟提醒 <|KKv5[
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]MqH13`)A
13、说明:一条sql 语句搞定数据库分页 %nDPM? aO
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 <?q&PCAn^
14、说明:前10条记录 G1#Bb5q:
select top 10 * form table1 where 范围 ]YisZE4s
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.) RE`J"&
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) egxJ3.
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 )Dk0V!%N
(select a from tableA ) except (select a from tableB) except (select a from tableC) cXLV"d
17、说明:随机取出10条数据 rZ8Y=) e
select top 10 * from tablename order by newid() (n":]8}
18、说明:随机选择记录 WuP([8
select newid() P`Hd*xh".j
19、说明:删除重复记录 _V_8p)%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) t6<sNzF&
20、说明:列出数据库里所有的表名 /XWPN(JC?
select name from sysobjects where type='U' [#hl}q(P#
21、说明:列出表里的所有的 W%cj39$
select name from syscolumns where id=object_id('TableName') rj2r# {[
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。 Vq .!(x
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 Kc JP^
显示结果: c:?#zX
type vender pcs %vf2||a$BS
电脑 A 1 Wvut)T
电脑 A 1 'K;4102\
光盘 B 2 |l6<GWG+
光盘 A 2 gCk y(4
手机 B 3 =E{{/%u{{S
手机 C 3 !OuTXa,IH
23、说明:初始化表table1 s%L"
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TRUNCATE TABLE table1 (l3UNP
24、说明:选择从10到15的记录 n3l"L|W^(<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc s{"`=dKT
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三、技巧 we:5gK&
1、1=1,1=2的使用,在SQL语句组合时用的较多 ? !oVf>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, yv!''F:9F
如: TzevC$m;z
if @strWhere !='' ;G4HMtL
begin hdsgOu
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 8zCGMhd
end @Q$/eL
else zgq_0w~X
begin MUCJ/GF*
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' v'
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end wQdW
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我们可以直接写成 !ulLGmUn
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 5|6z1{g8
2、收缩数据库 ."!8B9s
--重建索引 PBAz`y2
DBCC REINDEX YL9t3]
DBCC INDEXDEFRAG Lilk8|?#W
--收缩数据和日志 !dbA (
DBCC SHRINKDB ^EuyvftZ
DBCC SHRINKFILE os(Jr!p_=
3、压缩数据库 shDt&_n
dbcc shrinkdatabase(dbname) HjUw[Yz+6
4、转移数据库给新用户以已存在用户权限 JR a*;_
exec sp_change_users_login 'update_one','newname','oldname' (}~eD
go wCq)w=,
5、检查备份集 nIT ^'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Kc9mI>u H
6、修复数据库 ~G{$ P'[
ALTER DATABASE [dvbbs] SET SINGLE_USER WnJLX ^;
GO 8)-t91hkL
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK vYMbson}
GO 6XOpB^@
ALTER DATABASE [dvbbs] SET MULTI_USER XY+aunLf
GO G"U>fwFuK
7、日志清除 _~wV{ yp
SET NOCOUNT ON QN}3S0
DECLARE @LogicalFileName sysname, +3o)L?:g
@MaxMinutes INT, +4:+qGAJ{
@NewSize INT j6R{
USE tablename -- 要操作的数据库名 hBfzU\*0H
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t0asW5f
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 2LxVt@_R!%
@NewSize = 1 -- 你想设定的日志文件的大小(M) OuBMVn
-- Setup / initialize eX
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DECLARE @OriginalSize int ,$6MM6W;-F
SELECT @OriginalSize = size ~\)&{'
FROM sysfiles d'AviW>
WHERE name = @LogicalFileName E9Xk8w'+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /_k hFw
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,],JI|Rl8c
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' UwL"%0u
FROM sysfiles ]!tYrSM!
WHERE name = @LogicalFileName 2;?wN`}5g=
CREATE TABLE DummyTrans 3ciVjH>i
(DummyColumn char (8000) not null) 7ck0S+N'b
DECLARE @Counter INT, p=`x
@StartTime DATETIME, hml\^I8Q>F
@TruncLog VARCHAR(255) sen{f^U
SELECT @StartTime = GETDATE(), ~gi( 1<#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' L$TKO,T
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p\]LEP\z,
EXEC (@TruncLog) h4B#T'b
-- Wrap the log if necessary. TNFm7}=
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired R 6yvpH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aD/,c1
AND (@OriginalSize * 8 /1024) > @NewSize <R~~yW:H
BEGIN -- Outer loop. *Xtc`XH
SELECT @Counter = 0 WlQ&Yau
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Etr8lm E
BEGIN -- update =iK6/ y`
INSERT DummyTrans VALUES ('Fill Log') GaK_9Eg-2
DELETE DummyTrans E]eqvT NH
SELECT @Counter = @Counter + 1 [;CqvD<S
END 0Li'a{n 2
EXEC (@TruncLog) ;DgX"Uzm
END v/TlXxfil
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ik:)-GV;s
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3~3(G[w
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L%s4snE
FROM sysfiles D917[<$
WHERE name = @LogicalFileName pXT$Y8M
DROP TABLE DummyTrans 0[!gk]p
SET NOCOUNT OFF In9|n^=H@
8、说明:更改某个表 jVFRq T%
exec sp_changeobjectowner 'tablename','dbo' tCCi|*P
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9、存储更改全部表 iB`WXU
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Ye=7Y57Nr
@OldOwner as NVARCHAR(128), |7Xpb
@NewOwner as NVARCHAR(128) u FYQ^
AS QWW7I.9r
DECLARE @Name as NVARCHAR(128) I`$I0
DECLARE @Owner as NVARCHAR(128) hIO4%RQj_
DECLARE @OwnerName as NVARCHAR(128) vzrD"
DECLARE curObject CURSOR FOR ::72~'tw
select 'Name' = name, !q6V@&
'Owner' = user_name(uid) ;pNbKf:
from sysobjects *sIG&
where user_name(uid)=@OldOwner l[\,*C
order by name g d}TTe
OPEN curObject teS0F
FETCH NEXT FROM curObject INTO @Name, @Owner _:=OHURc
WHILE(@@FETCH_STATUS=0) y[@j0xlO
BEGIN ZR q}g:
if @Owner=@OldOwner e}O -I
begin NF\^'W@N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) UE`4$^qs
exec sp_changeobjectowner @OwnerName, @NewOwner M>H^<N}'A
end 0)Xue9AS
-- select @name,@NewOwner,@OldOwner cLko
FETCH NEXT FROM curObject INTO @Name, @Owner 'SD|ObBY
END Y <i}"eI*
close curObject -MW(={#
deallocate curObject Y./}zCT
GO RdVis|7o
10、SQL SERVER中直接循环写入数据 K\E]X\:
declare @i int 4C9"Q,o%&
set @i=1 R6@~
while @i<30 a~eLkWnh<k
begin @?cXa: tX
insert into test (userid) values(@i) b=
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set @i=@i+1 :2Rci`lp
end 8J?`_
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) !#4HGjPI
Dateadd(wk,datediff(wk,0,getdate()),6) kR~4O$riG
Dateadd(mm,datediff(mm,0,getdate()),0) mF:s-+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ABe^]HlH
Dateadd(yy,datediff(yy,0,getdate()),0) TNT"2FoBd
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) GKx,6E#JM
上面的SQL代码只是一个时间段 sS2E8Z2
Dateadd(wk,datediff(wk,0,getdate()),-1) "KE38`NL
Dateadd(wk,datediff(wk,0,getdate()),6) TN@JPoH
就是表示本周时间段. +-YuBVHL
下面的SQL的条件部分,就是查询时间段在本周范围内的: T&MS_E&;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M*@aA
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而在存储过程中 QDT{Xg*I
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) rbZ6V :
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) OO+#KyU