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。 .I[uXd
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一、基础 BB9Z?}
1、说明:创建数据库 HnrT;!C~
CREATE DATABASE database-name B2VUH..am
2、说明:删除数据库 #AE'arT<
drop database dbname 9MVW~V
3、说明:备份sql server X#IVjc:&L
--- 创建 备份数据的 device W&)OiZN
USE master t[%9z6t
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' DqbN=[!X~n
--- 开始 备份 W%)
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BACKUP DATABASE pubs TO testBack R|Y)ow51
4、说明:创建新表 Bx2E9/S3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !\^c9Pg|v
根据已有的表创建新表: e%#9|/uP
A:create table tab_new like tab_old (使用旧表创建新表) Bm1yBKjO
B:create table tab_new as select col1,col2... from tab_old definition only J=5G<
5、说明:删除新表 5{VrzzOK}
drop table tabname 9_oIAn:<
6、说明:增加一个列 x-Yt@}6mvl
Alter table tabname add column col type @:X~^K.
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。 %=%jy
7、说明:添加主键: Alter table tabname add primary key(col) KR#Bj?fz-H
说明:删除主键: Alter table tabname drop primary key(col) jO3Z2/#
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q lql(*
删除索引:drop index idxname $GPenQ~},
注:索引是不可更改的,想更改必须删除重新建。 DM"`If%3j
9、说明:创建视图:create view viewname as select statement :U^a0s%B
删除视图:drop view viewname ]Ocf %(
10、说明:几个简单的基本的sql语句 a'rN&*P
选择:select * from table1 where 范围 ^!!@O91T
插入:insert into table1(field1,field2) values(value1,value2) yD(0:g#
删除:delete from table1 where 范围 =DUsQN!
更新:update table1 set field1=value1 where 范围 &$|k<{j[<f
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Cj,fP[p#7
排序:select * from table1 order by field1,field2 [desc] ZI-)'
总数:select count as totalcount from table1 JuKj
求和:select sum(field1) as sumvalue from table1 Z'hW;^e%_z
平均:select avg(field1) as avgvalue from table1 BB>3Kj:|
最大:select max(field1) as maxvalue from table1 j'I$F1>Te
最小:select min(field1) as minvalue from table1 K'7i$bl%
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11、说明:几个高级查询运算词 #P<v[O/rA
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A: UNION 运算符 AS'a'x>8>,
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。 79z(n[^
B: EXCEPT 运算符 RV.*_FG
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。 /!ux P~2U
C: INTERSECT 运算符 Cir==7A0
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。 :;#Kg_bz
注:使用运算词的几个查询结果行必须是一致的。 L00,{g6wqb
12、说明:使用外连接 $*{PUj
A、left outer join: o
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 1B}6 zJ
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |r$Vb$z
B:right outer join: 5JBenTt
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。 )W(?wv!,
C:full outer join: 1)X%n)2pr
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。
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二、提升 j"7 z
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) L Lm{:T7
法一:select * into b from a where 1<>1 Nj@k|_1
法二:select top 0 * into b from a (G*--+Gn
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) gQCkoQi:j
insert into b(a, b, c) select d,e,f from b; h1:uTrtA
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) t=d~\_Oa
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >| rID
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _A;jtS)SY
4、说明:子查询(表名1:a 表名2:b)
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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) b(&2/|hd
5、说明:显示文章、提交人和最后回复时间 :w_Zr5H]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b mpIRe@#Z
6、说明:外连接查询(表名1:a 表名2:b) V#'sH
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -"UK NB!
7、说明:在线视图查询(表名1:a ) (&=-o(
select * from (SELECT a,b,c FROM a) T where t.a > 1; SL?
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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 D: NBb!
select * from table1 where time between time1 and time2 MLG%+@\
select a,b,c, from table1 where a not between 数值1 and 数值2 "[q/2vC
9、说明:in 的使用方法 FAz shR
select * from table1 where a [not] in ('值1','值2','值4','值6') k9vr6We'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 I QS|
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: ={o>g'
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 ..... s=!
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12、说明:日程安排提前五分钟提醒 'p80X^g
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7%c9 nY
13、说明:一条sql 语句搞定数据库分页 #KF:(2
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 *RD9gIze
14、说明:前10条记录 dP=1*
select top 10 * form table1 where 范围 _>9|"seR
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.) DGz'Dn
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ,2qJXMg"=$
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 |<96H8
(select a from tableA ) except (select a from tableB) except (select a from tableC) Zz'(!h Uy
17、说明:随机取出10条数据 Ia=wf"JS)
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 bc}U &X<
select newid() vRpMZ)e
19、说明:删除重复记录 vQ#$.*Cvn
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) G|Yw
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20、说明:列出数据库里所有的表名 !h4S`2oZ/
select name from sysobjects where type='U' mnzamp
21、说明:列出表里的所有的 O[+S/6uy
select name from syscolumns where id=object_id('TableName') Oz#$x
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。 3;zJ\a.+
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 m"t\@f
显示结果: ^/47*vcN5
type vender pcs Ek~Qp9B
电脑 A 1 2asA]sY
电脑 A 1 Ok/~E
光盘 B 2 Am'5|
光盘 A 2 EDcR:Dw3
手机 B 3 `Rub"zM
手机 C 3 )mz [2Sfg
23、说明:初始化表table1 d kHcG&)
TRUNCATE TABLE table1 0?qXD O&~
24、说明:选择从10到15的记录 gbL99MZ@~
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #oSQWC=T
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三、技巧 : ~"^st_[!
1、1=1,1=2的使用,在SQL语句组合时用的较多 =QHW>v
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }QU9+<Z[r
如: }L^Yoq]
if @strWhere !='' IsxPm9P2<
begin (cAv :EKpo
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere +Pd&YfU9
end _A|1_^[G(
else ,UopGlA
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begin 4(o: #9I
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $qYtN`b,
end iT1"Le/N
我们可以直接写成 c[}h( jkP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Q:&,8h[
2、收缩数据库 ~Z!xS
--重建索引 <6Q]FH!6
DBCC REINDEX XAR~d6iZ
DBCC INDEXDEFRAG \:mx Ri
--收缩数据和日志 Po'yr] pr
DBCC SHRINKDB {";5n7<<)
DBCC SHRINKFILE
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3、压缩数据库 %H75u6
dbcc shrinkdatabase(dbname) ^N#kW-i
4、转移数据库给新用户以已存在用户权限 'C)^hj.
exec sp_change_users_login 'update_one','newname','oldname' '}dlVf
go C(Ujx=G+3
5、检查备份集 "(PJh\S>S
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3Q*K+(`{
6、修复数据库 r5%K2q{
ALTER DATABASE [dvbbs] SET SINGLE_USER #F@53N
GO %_;q<@9)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK \u?z:mV
GO M7^PWC
ALTER DATABASE [dvbbs] SET MULTI_USER [X0Wfb}{
GO JM!rop^
7、日志清除 ^crk8O@Fw
SET NOCOUNT ON H$zjN8||"
DECLARE @LogicalFileName sysname, 9a 9<I
@MaxMinutes INT, eUPG){"
@NewSize INT '31pb9@fH
USE tablename -- 要操作的数据库名 EgM.wQHR]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +Gqh
@MaxMinutes = 10, -- Limit on time allowed to wrap log. yx"xbCc#
@NewSize = 1 -- 你想设定的日志文件的大小(M) )28Jz6.I
-- Setup / initialize osyY+)G'sV
DECLARE @OriginalSize int ,LKY?=T$z
SELECT @OriginalSize = size YNA %/
FROM sysfiles ?6+GE_VZ
WHERE name = @LogicalFileName 6[,*2a8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X[_w#Hwp-
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + uy)iB'st&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >DVjO9Kf
FROM sysfiles u4bPj2N8I
WHERE name = @LogicalFileName ..V6U"/
CREATE TABLE DummyTrans ]Cnj=\'
(DummyColumn char (8000) not null) 9-[g/qrF
DECLARE @Counter INT, nF0$
@StartTime DATETIME, 8~AO~
@TruncLog VARCHAR(255) zD}dvI}
SELECT @StartTime = GETDATE(), "P\k_-a'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Y,I0o{,g
DBCC SHRINKFILE (@LogicalFileName, @NewSize) jJdw\`
EXEC (@TruncLog) 7].tt
-- Wrap the log if necessary. oNY;z-QK
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \g< M\3f
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) PeEf=3
AND (@OriginalSize * 8 /1024) > @NewSize :]iV*zo_
BEGIN -- Outer loop. B;9X{"
SELECT @Counter = 0 s`GwRH<#
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *2N$l>ql:k
BEGIN -- update <^6|ZgR
INSERT DummyTrans VALUES ('Fill Log') %>`0hk88
DELETE DummyTrans YQe9g>G&
SELECT @Counter = @Counter + 1 Rd|};-
END jv<BGr=4;
EXEC (@TruncLog) O&!>C7
END S~0 mY}
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ta`=c0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + YbB8D-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J5h;~l!y
FROM sysfiles -twV?~f
WHERE name = @LogicalFileName .9{Sr[P
DROP TABLE DummyTrans [U@#whE O
SET NOCOUNT OFF r7o63]
8、说明:更改某个表 G/>upnA{w
exec sp_changeobjectowner 'tablename','dbo' 5VdF^.:u
9、存储更改全部表 wG6>.`:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch hd1(q33
@OldOwner as NVARCHAR(128), iIji[>qz
@NewOwner as NVARCHAR(128) w^EAk(77
AS 0FD#9r
DECLARE @Name as NVARCHAR(128) bDVz+*bU}
DECLARE @Owner as NVARCHAR(128) (Em^qN
DECLARE @OwnerName as NVARCHAR(128) z[Xs=S!]I
DECLARE curObject CURSOR FOR LPX@oh a
select 'Name' = name, P,lKa.
'Owner' = user_name(uid) *t.L` G
from sysobjects S]mXfB(mh
where user_name(uid)=@OldOwner fBBNP)
order by name 7.-Q9xv
OPEN curObject TbbtD"b?
FETCH NEXT FROM curObject INTO @Name, @Owner Bpt%\LK\~O
WHILE(@@FETCH_STATUS=0) Pd9qY
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BEGIN h'YC!hjp
if @Owner=@OldOwner :S'P
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begin p&~8N#I#
set @OwnerName = @OldOwner + '.' + rtrim(@Name) PrqN5ND
exec sp_changeobjectowner @OwnerName, @NewOwner vp7J';
end '1{co/Y
-- select @name,@NewOwner,@OldOwner *m6~x-x
FETCH NEXT FROM curObject INTO @Name, @Owner oG~a`9N%C
END !PJD+SrG
close curObject v
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deallocate curObject 9gR@Q%b)
GO 1eQa54n
10、SQL SERVER中直接循环写入数据 C1_':-4
declare @i int 19O /Q,9
set @i=1 MLg+ 9y
while @i<30 p+#$S4V
begin q66!xhp;?
insert into test (userid) values(@i) sc
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set @i=@i+1 XA75tU[#
end \g&P5
小记存储过程中经常用到的本周,本月,本年函数 Hh`x>{,|S
Dateadd(wk,datediff(wk,0,getdate()),-1) sT:$:=
Dateadd(wk,datediff(wk,0,getdate()),6) ;zVtJG`
Dateadd(mm,datediff(mm,0,getdate()),0) 6qg_&woJ3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0.C[/ u[
Dateadd(yy,datediff(yy,0,getdate()),0) l?GN& u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) $?RxmWsP
上面的SQL代码只是一个时间段 /KGVMBifM
Dateadd(wk,datediff(wk,0,getdate()),-1) w6 0I;.hy
Dateadd(wk,datediff(wk,0,getdate()),6) kSj,Pl\NC
就是表示本周时间段. ?EQ]f34
下面的SQL的条件部分,就是查询时间段在本周范围内的: EwDFU K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) YLs%u=e($
而在存储过程中 :4RD.l
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ^-Ob($(\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) +|(-7"