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。 -_n Qn
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一、基础 _!1LV[x!s
1、说明:创建数据库 F}{%*EJ
CREATE DATABASE database-name QP.Lq}
2、说明:删除数据库 -9FGFBm4]
drop database dbname ld]*J}cw
3、说明:备份sql server :0:Tl/))
--- 创建 备份数据的 device ?'0!>EjY"
USE master eMnK@J
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' mP\V.^
--- 开始 备份 .F8[;+
BACKUP DATABASE pubs TO testBack O
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4、说明:创建新表 Lo'pNJH;$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Oe1WnS 7(]
根据已有的表创建新表: z(A[xN@/W<
A:create table tab_new like tab_old (使用旧表创建新表) 1W'Ai"DLw
B:create table tab_new as select col1,col2... from tab_old definition only SbGdcCB
5、说明:删除新表 yn}Dj9(q
drop table tabname H;4QuB'^
6、说明:增加一个列 ,B'=$PO%
Alter table tabname add column col type y:98}gW`n
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 AC1RP`c
7、说明:添加主键: Alter table tabname add primary key(col) K7`6G[RMb
说明:删除主键: Alter table tabname drop primary key(col) hUi@T}aA|
8、说明:创建索引:create [unique] index idxname on tabname(col....) DAb/B
删除索引:drop index idxname ;iuwIdo6c
注:索引是不可更改的,想更改必须删除重新建。 tgKr*8t{
9、说明:创建视图:create view viewname as select statement pM@8T25=
删除视图:drop view viewname GqxnB k1
10、说明:几个简单的基本的sql语句 dvjj"F'Bf
选择:select * from table1 where 范围 UgAp9$=z
插入:insert into table1(field1,field2) values(value1,value2) 0]bt}rh
删除:delete from table1 where 范围 fY9+m}$S$
更新:update table1 set field1=value1 where 范围 exJc[G&t(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^%,{R},s
排序:select * from table1 order by field1,field2 [desc] YA$YT8iMe
总数:select count as totalcount from table1 ,5v'hG
求和:select sum(field1) as sumvalue from table1 Qz(2Iu{E]
平均:select avg(field1) as avgvalue from table1 c+3`hVV
最大:select max(field1) as maxvalue from table1 QO}~"lMj
最小:select min(field1) as minvalue from table1 SM8N*WdiU
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11、说明:几个高级查询运算词 w@^J.7h^
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A: UNION 运算符 =F$?`q`
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。 **%&|9He
B: EXCEPT 运算符 $x'jf?zs!
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 pL1ABvBB
C: INTERSECT 运算符 ;Va(l$zD
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。 Q&:)D7m\)S
注:使用运算词的几个查询结果行必须是一致的。 rQ{|0+l
12、说明:使用外连接 c ^ds|7i]a
A、left outer join: C
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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。 jKmjZz8L]%
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 # &.syD#
B:right outer join: /al56n
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。 FTCIfW
C:full outer join: x9>$197
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。 */h(4Hz
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二、提升 y!gPBkG&3n
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) xR0*w7YE
法一:select * into b from a where 1<>1 V8 8u-
法二:select top 0 * into b from a &zF>5@fM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) UDr1t n
insert into b(a, b, c) select d,e,f from b; ]%D!-[C%1
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) Pv5S k8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 F%-@_IsG#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. pRV.\*:c
4、说明:子查询(表名1:a 表名2:b) P^<3 Z)L
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) 3%'`^<-V
5、说明:显示文章、提交人和最后回复时间 VQpt1cK*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b w>j5oz}
6、说明:外连接查询(表名1:a 表名2:b) CWkWW/ZI
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "}Om0rB}1
7、说明:在线视图查询(表名1:a ) tcj"rV{G
select * from (SELECT a,b,c FROM a) T where t.a > 1; <@(\z
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 >u>
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select * from table1 where time between time1 and time2 b\ED<'
select a,b,c, from table1 where a not between 数值1 and 数值2 :bct+J}l~
9、说明:in 的使用方法 f4 S:L&
select * from table1 where a [not] in ('值1','值2','值4','值6') xcw:H&\w6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Oh1U=V2~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) OU%"dmSDk
11、说明:四表联查问题: g/.FJ-I*
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 ..... M}o.= Iqa
12、说明:日程安排提前五分钟提醒 Ld*Ds!*'/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 #a=]h}&1?
13、说明:一条sql 语句搞定数据库分页 *,G<X^
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 ivgX o'=
14、说明:前10条记录 ;xiN<f4B
select top 10 * form table1 where 范围 )8oyo~4?
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.) |iUF3s|?
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 9ia&/BT7"z
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 [8za=B/
(select a from tableA ) except (select a from tableB) except (select a from tableC) kEq~M10
17、说明:随机取出10条数据 2?%*UxcO
select top 10 * from tablename order by newid() dY}5Kmt
18、说明:随机选择记录 HE+' fQ!R
select newid() MXaik+2
19、说明:删除重复记录 >bV3~m$a+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) |.Vgk8oTl
20、说明:列出数据库里所有的表名 v];YC6shx
select name from sysobjects where type='U' [!%5(Ro_
21、说明:列出表里的所有的 t`Bk2Cc)+
select name from syscolumns where id=object_id('TableName') }Q: CZ
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。 wqDf\k}'v
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 VQ('ejv}/
显示结果: L;:PeYPL
type vender pcs k?7"r4Vc)S
电脑 A 1 Ewz cB\m
电脑 A 1 3\Xk)a_
光盘 B 2 }Y7P2W+4?
光盘 A 2 _qPKdGoM
手机 B 3 ]zj#X\
手机 C 3 17'd~-lE
23、说明:初始化表table1 t8RtJ2;
TRUNCATE TABLE table1 0"e["q{|
24、说明:选择从10到15的记录 bJMsB|r
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc t }4
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三、技巧 jX4$PfOhR
1、1=1,1=2的使用,在SQL语句组合时用的较多 &V+_b$
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $&.(7F^D
如: ^E/6vG
if @strWhere !='' OH>Gc-V
begin vUbgSI
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .^A4w;jPU
end D,..gsg
else ^/?7hbr
begin 8zMGpY#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rEp\ld
end C"n!mr{srt
我们可以直接写成 *P\lzM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Zq33R`
2、收缩数据库 ,1 H|{ <
--重建索引 1ik.|T<f0
DBCC REINDEX &I
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DBCC INDEXDEFRAG ;rL>{UhG
--收缩数据和日志 ?;Sg,.J
DBCC SHRINKDB IY.M#Q]
DBCC SHRINKFILE J[l7p6xk
3、压缩数据库 /Zs_G=\>
dbcc shrinkdatabase(dbname) &zgliT!If
4、转移数据库给新用户以已存在用户权限 "a;$uW@.6
exec sp_change_users_login 'update_one','newname','oldname' 7@ONCG
go j9c:SP5
5、检查备份集 , SUx!o
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' F}mt
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6、修复数据库 b'^<0c
ALTER DATABASE [dvbbs] SET SINGLE_USER E2}X[EoBF
GO KJ/Gv#Kj
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO b&E"r*i|
ALTER DATABASE [dvbbs] SET MULTI_USER
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GO dCn9]cj/
7、日志清除 n\Lsm
SET NOCOUNT ON N68]r3/K
DECLARE @LogicalFileName sysname, V1Ft3Msq
@MaxMinutes INT, hy#nK:B
@NewSize INT MA9E??p3\
USE tablename -- 要操作的数据库名 m~=VUhPd
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 B7qi|Fw
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1Bs t|
@NewSize = 1 -- 你想设定的日志文件的大小(M) =@O&$&
-- Setup / initialize %Qj$@.*:
DECLARE @OriginalSize int 8[@Y`j8
SELECT @OriginalSize = size ,]JIp~=nsh
FROM sysfiles J0bcW25
WHERE name = @LogicalFileName 0u"j^v
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )/!HI0TU
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + hyPS 6Y'1
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^3vI
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FROM sysfiles A]QGaWK
WHERE name = @LogicalFileName ;XNC+mPK
CREATE TABLE DummyTrans *>aVU'
(DummyColumn char (8000) not null) @ukL!AV?Y
DECLARE @Counter INT, ~)pZ5%C
@StartTime DATETIME, o:UNSr
@TruncLog VARCHAR(255) oJ5n*[qUI
SELECT @StartTime = GETDATE(), '_DB0_Dp
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 66B,Krz1n
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \COoU("
EXEC (@TruncLog) (JOR:
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-- Wrap the log if necessary. Zd)LVc[
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ,*V%
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >G?*rg4
AND (@OriginalSize * 8 /1024) > @NewSize !+Cc^{
BEGIN -- Outer loop. bly `mp8#
SELECT @Counter = 0 3LQu+EsS
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) n|.eL8lX.<
BEGIN -- update :Id8N~g
INSERT DummyTrans VALUES ('Fill Log') .+8#&Uy
DELETE DummyTrans
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SELECT @Counter = @Counter + 1 7ko}X,aC
END DV?c%z`YO
EXEC (@TruncLog) fi'zk
END LD WYFOGQ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &sn-;r
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + u9q#L.Ij
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U7zd7O
FROM sysfiles :`BG/
WHERE name = @LogicalFileName 7/]Ra
DROP TABLE DummyTrans }`0=\cKqn
SET NOCOUNT OFF k;Qm%B
8、说明:更改某个表 b:O_PS5h
exec sp_changeobjectowner 'tablename','dbo' :Eg4^,QX
9、存储更改全部表 [70 _uq
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Tsu\4
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@OldOwner as NVARCHAR(128), /i!/)]*-
@NewOwner as NVARCHAR(128) u1'l4VgT
AS }#Ji"e
DECLARE @Name as NVARCHAR(128) $WW7,
DECLARE @Owner as NVARCHAR(128) BUI#y `J
DECLARE @OwnerName as NVARCHAR(128) ~r})&`5
DECLARE curObject CURSOR FOR y9i+EV
select 'Name' = name, X+\=dhn69
'Owner' = user_name(uid) `}
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from sysobjects %dd B$(
where user_name(uid)=@OldOwner Xa'b@*o&
order by name &F0>V o
OPEN curObject =`MQKh,
FETCH NEXT FROM curObject INTO @Name, @Owner |gk"~D
WHILE(@@FETCH_STATUS=0) LDo~
BEGIN ?*q-u9s9
if @Owner=@OldOwner rV%;d[LB
begin MnY}U",
set @OwnerName = @OldOwner + '.' + rtrim(@Name) './qBJ
exec sp_changeobjectowner @OwnerName, @NewOwner $Vs5d=B
end ~O/B
-- select @name,@NewOwner,@OldOwner ? R[GSS1
FETCH NEXT FROM curObject INTO @Name, @Owner }*P;kV
END ucLh|}jJ5
close curObject R6GlQ G
deallocate curObject bV)h\:oC
GO ey>tUmt6?
10、SQL SERVER中直接循环写入数据 L?(1
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declare @i int T-oUcuQB
set @i=1 |BbrB[+ v[
while @i<30 h!Fh@%
begin xJ\sm8
insert into test (userid) values(@i) CF_2ez1u0y
set @i=@i+1 rUB67ok*
end *$t =Lh
小记存储过程中经常用到的本周,本月,本年函数 7W/55ZTmJ
Dateadd(wk,datediff(wk,0,getdate()),-1) sU^K5oo
Dateadd(wk,datediff(wk,0,getdate()),6) `9f7H
Dateadd(mm,datediff(mm,0,getdate()),0) Y$hLsM\%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) pug;1UZ
Dateadd(yy,datediff(yy,0,getdate()),0) .'1]2/ad
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) O~Dm|hP
上面的SQL代码只是一个时间段 We"\nOP
Dateadd(wk,datediff(wk,0,getdate()),-1) l2!ztK1^
Dateadd(wk,datediff(wk,0,getdate()),6) m0Uk*~Gz
就是表示本周时间段. `LTD|0;
下面的SQL的条件部分,就是查询时间段在本周范围内的: 2F,?}jJ.K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) unN*L
而在存储过程中 riglEA[^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) FePWr7Ze
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) RDqQ6(e"