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。 gf@Dy6<
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一、基础 /r6DPR0\
1、说明:创建数据库 D.~t#a A
CREATE DATABASE database-name *W
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2、说明:删除数据库 g&
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drop database dbname fi)ypv*
3、说明:备份sql server JB7]51WH@
--- 创建 备份数据的 device &}ow-u9c3
USE master
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Nx"?'-3Hm
--- 开始 备份 GupKM%kM
BACKUP DATABASE pubs TO testBack Fk\xq`3'c
4、说明:创建新表 <|@9]>z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _rv_-n]"o
根据已有的表创建新表: ~F-,Q_|-
A:create table tab_new like tab_old (使用旧表创建新表) >JhQ=j
B:create table tab_new as select col1,col2... from tab_old definition only 6{6tg>|L)
5、说明:删除新表 %F7k| Na
drop table tabname s]qfLC
6、说明:增加一个列 C*$/J\6xy
Alter table tabname add column col type >4c 1VEi
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 _1a2Z\
7、说明:添加主键: Alter table tabname add primary key(col) 1,E/So
说明:删除主键: Alter table tabname drop primary key(col) h
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8、说明:创建索引:create [unique] index idxname on tabname(col....) P-C_sj A7
删除索引:drop index idxname GUxhCoxb
注:索引是不可更改的,想更改必须删除重新建。 6ZE]7~X
9、说明:创建视图:create view viewname as select statement Nb6HM~
删除视图:drop view viewname QB7<$Bp
10、说明:几个简单的基本的sql语句 {!w]t?h
选择:select * from table1 where 范围 5BZ5Gl3
插入:insert into table1(field1,field2) values(value1,value2) 2WoB ;=
删除:delete from table1 where 范围 '"&?u8u)
更新:update table1 set field1=value1 where 范围 Z-p_hN b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \Z$*8z=
排序:select * from table1 order by field1,field2 [desc] [":x
总数:select count as totalcount from table1 1/ a,7Hl
求和:select sum(field1) as sumvalue from table1 *QLbrR
平均:select avg(field1) as avgvalue from table1 q^s$4 q
最大:select max(field1) as maxvalue from table1 bFpwq#PDW>
最小:select min(field1) as minvalue from table1 9}=Fdt
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11、说明:几个高级查询运算词 PrCq
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A: UNION 运算符 C-(&zwj?!
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 b(yY.L=K
B: EXCEPT 运算符 TM+7>a$
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。 8L#sg^1V
C: INTERSECT 运算符 D`ZYF)[}J
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。 sG3%~
注:使用运算词的几个查询结果行必须是一致的。 {MHr]A}X\
12、说明:使用外连接 @M1U)JoQ
A、left outer join: $I.'7
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 FY'f{gD^
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [W2k#-%G
B:right outer join: #q\C"N5ip
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ;RR)C@n1
C:full outer join: `
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 k,?k37%T]
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二、提升 U@9n7F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6 R!0v8
法一:select * into b from a where 1<>1 uB%`Bx'OW
法二:select top 0 * into b from a gw H6r3=y(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =0Nd\
insert into b(a, b, c) select d,e,f from b; 'b-}KDP
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) q|~9%Pujg
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 EprgLZ1B
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. qZ4DO*%b3
4、说明:子查询(表名1:a 表名2:b) H)5]K9D
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) )T^hyi$
5、说明:显示文章、提交人和最后回复时间 `8L7pbS%,Q
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b O @l `D`
6、说明:外连接查询(表名1:a 表名2:b) Z@1rs#
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c pvX\kX3}
7、说明:在线视图查询(表名1:a ) 6,!]x>B
select * from (SELECT a,b,c FROM a) T where t.a > 1; >Zr`9$i
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 :5ji.g* 0
select * from table1 where time between time1 and time2 r!;NH3 *
select a,b,c, from table1 where a not between 数值1 and 数值2 !a
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9、说明:in 的使用方法 +;vfn>^!b
select * from table1 where a [not] in ('值1','值2','值4','值6') /V,:gLpQ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7y:J@fh<
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5[0n'uH
11、说明:四表联查问题: wL:3RZB
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 8^O|Aa$IF:
12、说明:日程安排提前五分钟提醒 4h-y'&Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Gv<K#@9T
13、说明:一条sql 语句搞定数据库分页 E0GpoG5C
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 Pd>hd0!.%
14、说明:前10条记录 <@oK^ja
select top 10 * form table1 where 范围 C,Ch6Ph
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.) A;h~Fx6s
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :}Z+K*%o-
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 ,9=a(j"
(select a from tableA ) except (select a from tableB) except (select a from tableC) !fZxK CsQ
17、说明:随机取出10条数据 v,kedKcxv'
select top 10 * from tablename order by newid() :=-h'<D
18、说明:随机选择记录 ,<%],-Lt[
select newid() 9'}m797I'
19、说明:删除重复记录 QH+Oi&xH
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Pj^6.f+
20、说明:列出数据库里所有的表名 a6[bF
select name from sysobjects where type='U' [&e}@!8O`
21、说明:列出表里的所有的 oM J5;
select name from syscolumns where id=object_id('TableName') g,\<fY+4
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。 m,'u_yK
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 gQ&FO~cr
显示结果: w!h!%r
type vender pcs }y'KS:Jb
电脑 A 1 @zE_fL
电脑 A 1 k
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光盘 B 2 A!SHt7ysJ
光盘 A 2 tlc&Wx
手机 B 3 !tN]OQ)'
手机 C 3 Tf` ~=fg%
23、说明:初始化表table1 o[_{\
TRUNCATE TABLE table1 rqifjsv
24、说明:选择从10到15的记录 s<n5^Vxy
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [5>0om5
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三、技巧 Y*J,9
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,myl9s
"where 1=1" 是表示选择全部 "where 1=2"全部不选, EFhe``
如: =Bl#CE)X
if @strWhere !='' H~fZA)W 4Y
begin 5X'[{'i,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #k*e>d$
end &vo]l~.
else ;4%^4<+3
begin 0Bb amU
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' N_h)L`
end 2UA h^i-^
我们可以直接写成 "|(+~8[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere n hS=t8H
2、收缩数据库 ur"ckuG!9
--重建索引 d.sxB}_O
DBCC REINDEX njX!Ez
DBCC INDEXDEFRAG 6*Rz}RQ
--收缩数据和日志 LC2t,!RRl&
DBCC SHRINKDB ]hc.cj`\W&
DBCC SHRINKFILE [
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3、压缩数据库 y1B3F5
dbcc shrinkdatabase(dbname) J1hc :I<;
4、转移数据库给新用户以已存在用户权限 1Sr@$+VGO
exec sp_change_users_login 'update_one','newname','oldname' LsoP >vJG
go uee2WGD
5、检查备份集 \f05(ld
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &K/5AH"q
6、修复数据库 kF`2%g+
ALTER DATABASE [dvbbs] SET SINGLE_USER Y}Y2Vx
GO !'[f!vsyM{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK [*Wq6n
GO Jr|"` f%V
ALTER DATABASE [dvbbs] SET MULTI_USER >^{}Hjt
GO $s5LzJn
7、日志清除 C&D!TR!K
SET NOCOUNT ON RKx"
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DECLARE @LogicalFileName sysname, YOd0dKe
@MaxMinutes INT, 7jvf:#\LtL
@NewSize INT }]'Z~5T
USE tablename -- 要操作的数据库名 ['Hl$2 j
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 0PjWfM8%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. k& 2U&
@NewSize = 1 -- 你想设定的日志文件的大小(M) -$>R;L
-- Setup / initialize LY-fp+
DECLARE @OriginalSize int QQj)"XJ29
SELECT @OriginalSize = size ?v\A&d
FROM sysfiles K]1A,Q
WHERE name = @LogicalFileName mY+Jju1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + P?\ IlziCB
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + q{nNWvL
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' nZ0-
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FROM sysfiles jA?A)YNQb
WHERE name = @LogicalFileName )k&<D*5s
CREATE TABLE DummyTrans \GO^2&g(
(DummyColumn char (8000) not null) r8A
DECLARE @Counter INT, g:7S/L0]
@StartTime DATETIME, (Z fY/
@TruncLog VARCHAR(255) YAYPof~A$l
SELECT @StartTime = GETDATE(), @2na r<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' g ]e^;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) c_"]AhV~Mg
EXEC (@TruncLog) 9LI#&\lba
-- Wrap the log if necessary. |7LhE+E
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ?Id3#+-O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) b3N1SC:Wn
AND (@OriginalSize * 8 /1024) > @NewSize )v
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BEGIN -- Outer loop. mmE\=i~
SELECT @Counter = 0 %}elh79H*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) MqDz cB]
BEGIN -- update '_N~PoV
INSERT DummyTrans VALUES ('Fill Log') .B_LQ;0:
DELETE DummyTrans [+\=x[q
SELECT @Counter = @Counter + 1 6vAq&Y{JB'
END 9)9p<(b$
EXEC (@TruncLog) hd^?mZ
END x1VBO.t=*
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >x]b"@Hkw
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + CoO..
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' gi\2bzWkbX
FROM sysfiles :m#[V7
WHERE name = @LogicalFileName c>!zJAB
DROP TABLE DummyTrans K%h9'}pq>1
SET NOCOUNT OFF @~,&E*X! .
8、说明:更改某个表 V3r1|{Z(
exec sp_changeobjectowner 'tablename','dbo' lI~T>Lel2
9、存储更改全部表 _4Z|O]
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch jM]B\cvN
@OldOwner as NVARCHAR(128), Aru=f~!
@NewOwner as NVARCHAR(128) FOV%\=Hl
AS v'na{"
DECLARE @Name as NVARCHAR(128) $a.fQ<,\X
DECLARE @Owner as NVARCHAR(128) k<(G)7'gm
DECLARE @OwnerName as NVARCHAR(128) HI&N&a9C
DECLARE curObject CURSOR FOR -5B>2K F
select 'Name' = name, (cAWT,
'Owner' = user_name(uid) Aj#bhv
from sysobjects tUU`R{=(
where user_name(uid)=@OldOwner 8S/SXyS
order by name u5zL;C3O
OPEN curObject {BPNb{dBKr
FETCH NEXT FROM curObject INTO @Name, @Owner <q\OREMsq
WHILE(@@FETCH_STATUS=0) 69/aP=
BEGIN HEh,Cf7`'
if @Owner=@OldOwner p)2
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begin }% 2hBl/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9j<qi\SSI
exec sp_changeobjectowner @OwnerName, @NewOwner r&!Ebe-
end %:Mi6sR|
-- select @name,@NewOwner,@OldOwner y.vYT{^
FETCH NEXT FROM curObject INTO @Name, @Owner ^F\RM4|,
END R<(kiD\?]
close curObject {;mT.[
deallocate curObject t7#lRp&
GO R. :~e
10、SQL SERVER中直接循环写入数据 $.HZz
declare @i int ,'!x9 `
set @i=1 9lXjB_wG>
while @i<30 } V *
begin d?[gd(O
insert into test (userid) values(@i) 0#Ivo<V
set @i=@i+1 8k~$_AT>u
end v<0\+}T1R
小记存储过程中经常用到的本周,本月,本年函数 5>CmWMQ
Dateadd(wk,datediff(wk,0,getdate()),-1) C.]\ 4e
Dateadd(wk,datediff(wk,0,getdate()),6) 4gD;X NrV
Dateadd(mm,datediff(mm,0,getdate()),0) :DWvH,{+&
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Dnk}
Dateadd(yy,datediff(yy,0,getdate()),0) l/*NscYtQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6="Qwrk
上面的SQL代码只是一个时间段 OeMI
Dateadd(wk,datediff(wk,0,getdate()),-1) vX?MB
Dateadd(wk,datediff(wk,0,getdate()),6) Lsu_f'p0
就是表示本周时间段. #dO8) t
下面的SQL的条件部分,就是查询时间段在本周范围内的: qe^d6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) fG dT2}gd
而在存储过程中 80m<OW1
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;[nomxu|?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) vNWCv