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。 6):Xzx,
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一、基础 f8'MP9Lv
1、说明:创建数据库 v$Uhm</|19
CREATE DATABASE database-name ,PECYwegkt
2、说明:删除数据库 5wT>N46UX
drop database dbname !8R@@,_v
3、说明:备份sql server nNaXp*J
--- 创建 备份数据的 device &:3Z.G
USE master ,O]l~)sr|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R J~%0
--- 开始 备份 mI7~c;~
BACKUP DATABASE pubs TO testBack \?Mf _
4、说明:创建新表 -.iNNM&a
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L9FHgl?
根据已有的表创建新表: }gGkV]
A:create table tab_new like tab_old (使用旧表创建新表) <&<,l58[c
B:create table tab_new as select col1,col2... from tab_old definition only {Dr@HP/x=s
5、说明:删除新表 Qx)Jtb0`V
drop table tabname )R?;M
6、说明:增加一个列 ECcZz.
Alter table tabname add column col type p!zJ;rh)
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 T6M+|"92
7、说明:添加主键: Alter table tabname add primary key(col) a{'Z5ail
说明:删除主键: Alter table tabname drop primary key(col) B= X,7
8、说明:创建索引:create [unique] index idxname on tabname(col....) zl%>`k!>
删除索引:drop index idxname lA^+Flh
注:索引是不可更改的,想更改必须删除重新建。 &(blN.2
9、说明:创建视图:create view viewname as select statement .lN s4e
删除视图:drop view viewname ~n?>[88"
10、说明:几个简单的基本的sql语句 ^"i~DC
选择:select * from table1 where 范围 nfdq y)
插入:insert into table1(field1,field2) values(value1,value2) Ai"-w"
删除:delete from table1 where 范围 vq!uD!lr
更新:update table1 set field1=value1 where 范围 &:5\"b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! fuX'~$b.fA
排序:select * from table1 order by field1,field2 [desc] "D][e'
总数:select count as totalcount from table1 LL*mgTQ
求和:select sum(field1) as sumvalue from table1 [/ M`
平均:select avg(field1) as avgvalue from table1 M4m$\~zf
最大:select max(field1) as maxvalue from table1 hhI)' $
最小:select min(field1) as minvalue from table1 '+Xlw
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11、说明:几个高级查询运算词 vjT( Q
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A: UNION 运算符 &miexSNeF
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。 EME.h&A\G`
B: EXCEPT 运算符 A,gEM4
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。 k`{7}zxS
C: INTERSECT 运算符 %Ym^{N
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。 ?rYT4vi
注:使用运算词的几个查询结果行必须是一致的。 )ChqATKg
12、说明:使用外连接 d3;qsUh$yv
A、left outer join: \qh*E#j
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 CC^E_j T
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c YDC&u8
B:right outer join: 3oy~=
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 w5=tlb
C:full outer join: %A/_5;PZ/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Q{g;J`Z)p
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二、提升 ``U^COD
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _-TA{21)
法一:select * into b from a where 1<>1 {eS|j=
法二:select top 0 * into b from a lB91An
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) `D$Jv N
insert into b(a, b, c) select d,e,f from b; M]]pTU((
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) gJ$K\[+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 jE2}p-2Q0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >Z.\J2wM<j
4、说明:子查询(表名1:a 表名2:b) >slm$~rv
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) rjx6Djo>
5、说明:显示文章、提交人和最后回复时间 {'En\e
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b x#.C4O09
6、说明:外连接查询(表名1:a 表名2:b) Ev"|FTI/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {LHR!~d}5f
7、说明:在线视图查询(表名1:a ) IuF_M<d,
select * from (SELECT a,b,c FROM a) T where t.a > 1; PQN@JaD
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 q@hzo>[
select * from table1 where time between time1 and time2 2{Vcb
select a,b,c, from table1 where a not between 数值1 and 数值2 }~K`/kvs
9、说明:in 的使用方法 \b=Pj!^gwb
select * from table1 where a [not] in ('值1','值2','值4','值6') &fa5laJb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]i<[d,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #>=j79~
11、说明:四表联查问题: ?S$i?\Qh
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 ..... gD`>Twa&6
12、说明:日程安排提前五分钟提醒 Vwk #qgnX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 r}#\BbCv;7
13、说明:一条sql 语句搞定数据库分页 0|&\'{
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 L|-98]8>
14、说明:前10条记录 66x?A0P
select top 10 * form table1 where 范围 CIU1R;
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.) %p^.|Me7
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q\ /uKQ
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 *Xo]-cKL0
(select a from tableA ) except (select a from tableB) except (select a from tableC) 5tjP6Z`!9`
17、说明:随机取出10条数据 L( T12s
select top 10 * from tablename order by newid() ML;*e "$
18、说明:随机选择记录 Wq*b~Lw
select newid() qyC=(v
19、说明:删除重复记录 E%oY7.~-
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) W[EKD 7
20、说明:列出数据库里所有的表名 gz2\H}
select name from sysobjects where type='U' @%k}FL=:t(
21、说明:列出表里的所有的 Q+4tIrd+
select name from syscolumns where id=object_id('TableName') Twn4lG4~
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。 \`V;z~@iA
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 toN^0F?Qm
显示结果: 3(TsgP>`
type vender pcs akw,P$i
电脑 A 1 .#02
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电脑 A 1 n
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光盘 B 2 su*Pk|6%
光盘 A 2 WJ<^E"^
手机 B 3 !EUan
手机 C 3 z'T)=ycT
23、说明:初始化表table1 lL1k.&|5m
TRUNCATE TABLE table1 Ookh<ES>
24、说明:选择从10到15的记录 4DZ-bt'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0TpK#OlI|c
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三、技巧 {uzf"%VtP
1、1=1,1=2的使用,在SQL语句组合时用的较多 U9b?i$
"where 1=1" 是表示选择全部 "where 1=2"全部不选, (/35pg6\
如: \%UkSO\nO3
if @strWhere !='' PkI:*\R
begin rE@T79"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ca+5=+X7
end KYzv$oK
else N F)~W#
begin Zd"^</ S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' %|s+jeUDn|
end |:8bNm5[
我们可以直接写成 J:V?EE,\-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6{=\7AY
2、收缩数据库 )GHq/:1W
--重建索引 iY21Ql%
DBCC REINDEX &b:1I7Cp*
DBCC INDEXDEFRAG Gea\,{E9xA
--收缩数据和日志 '],J$ge
DBCC SHRINKDB kc0E%odF.v
DBCC SHRINKFILE wI(M^8F_Mf
3、压缩数据库 Xh56T^,2
dbcc shrinkdatabase(dbname) -GxaV #{
4、转移数据库给新用户以已存在用户权限 yPq'( PV
exec sp_change_users_login 'update_one','newname','oldname' #U14-^7
go X&kp;W
5、检查备份集 G^ :C+/)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' HTG%t/S
6、修复数据库 41&\mx
ALTER DATABASE [dvbbs] SET SINGLE_USER EFz&N\2
GO R17?eucZ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 'inFKy'H
GO V:y'Qf2M
ALTER DATABASE [dvbbs] SET MULTI_USER %7|9sQ:
GO ZHa"isl$e
7、日志清除 @;"|@!l|
SET NOCOUNT ON .SWlp2!M5
DECLARE @LogicalFileName sysname, 4r45i:
@MaxMinutes INT, q<M2,YrbAI
@NewSize INT kGl~GOB
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USE tablename -- 要操作的数据库名 >7 ="8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Rb'|EiNPw
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
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@NewSize = 1 -- 你想设定的日志文件的大小(M) n@)K #
-- Setup / initialize ?`?)QE8
DECLARE @OriginalSize int OGl}-kw
SELECT @OriginalSize = size W)bLSL]`E
FROM sysfiles ?32&]iM
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WHERE name = @LogicalFileName FYpzQ6s~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + :=Nz}mUV
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ')cMiX\v
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' > ;*b|Ik
FROM sysfiles uLV#SQ=bZN
WHERE name = @LogicalFileName *}*FX+px)
CREATE TABLE DummyTrans A*\.NTM
(DummyColumn char (8000) not null) 5?x>9Ca
DECLARE @Counter INT, g%=z_
@StartTime DATETIME, a^I\ /&aw'
@TruncLog VARCHAR(255) " )1V]}+m
SELECT @StartTime = GETDATE(), )P
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2GDD!w#!j
DBCC SHRINKFILE (@LogicalFileName, @NewSize) *_d7E
EXEC (@TruncLog) #AJM6* G9
-- Wrap the log if necessary. vQ
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired HMNLa*CL'
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "]}
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AND (@OriginalSize * 8 /1024) > @NewSize glDu2a,Q
BEGIN -- Outer loop. ,
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SELECT @Counter = 0 5j?3a1l0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _z|65H
BEGIN -- update =c\>(2D
INSERT DummyTrans VALUES ('Fill Log') =%TWX[w
DELETE DummyTrans .[ICx
SELECT @Counter = @Counter + 1 Q ~#Wf?
END asppRL||
EXEC (@TruncLog) Li4zTR|U
END b0Ps5G\ u
SELECT 'Final Size of ' + db_name() + ' LOG is ' + W_"sM0
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,s"^kFl
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' p$]3'jw
FROM sysfiles vg32y /l]S
WHERE name = @LogicalFileName X}Ai-D
DROP TABLE DummyTrans [M=7M}f;
SET NOCOUNT OFF yPb" V
8、说明:更改某个表 m;GCc8
exec sp_changeobjectowner 'tablename','dbo' zHM(!\8K
9、存储更改全部表 #Lh;CSS
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 3YR!Mq$|~
@OldOwner as NVARCHAR(128), at,XB.}Z]
@NewOwner as NVARCHAR(128) <Zmg#
AS !Wntd\w
DECLARE @Name as NVARCHAR(128) KW pVw!
DECLARE @Owner as NVARCHAR(128) x??+~$}\*-
DECLARE @OwnerName as NVARCHAR(128) t.i 8
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DECLARE curObject CURSOR FOR D2Kp|F;
select 'Name' = name, YJT&{jYi
'Owner' = user_name(uid) j8^I z
from sysobjects L>Fa^jq5
where user_name(uid)=@OldOwner _-K2/6zy
order by name TNe l/
OPEN curObject @@Kp67Iv
FETCH NEXT FROM curObject INTO @Name, @Owner 3YOq2pW72G
WHILE(@@FETCH_STATUS=0) ymhtX6]
BEGIN kTOzSiq
if @Owner=@OldOwner 3
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begin KQ% GIz x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6
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exec sp_changeobjectowner @OwnerName, @NewOwner .ypL=~Rp
end yEqps3%
-- select @name,@NewOwner,@OldOwner ?]_$Dcmx
FETCH NEXT FROM curObject INTO @Name, @Owner ; F"g$_D0
END h+g_rvIG*
close curObject R'as0 u\
deallocate curObject l<58A7
GO spH7 /5}
10、SQL SERVER中直接循环写入数据 IL#"~D?
declare @i int hF~n)oQ
set @i=1 FXG]LoP
while @i<30 H)kwQRfu
begin 3nO]Ge"w'n
insert into test (userid) values(@i) {HltvO%8
set @i=@i+1 'CM|@Zz%
end *K8$eDNZ
小记存储过程中经常用到的本周,本月,本年函数 \kL3.W_
Dateadd(wk,datediff(wk,0,getdate()),-1) l*(8i ^
Dateadd(wk,datediff(wk,0,getdate()),6) @<hb6bo,N
Dateadd(mm,datediff(mm,0,getdate()),0) K7_UP&`=J
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !C':
Dateadd(yy,datediff(yy,0,getdate()),0) &
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 99e.n0
上面的SQL代码只是一个时间段 g[' ^L+hd
Dateadd(wk,datediff(wk,0,getdate()),-1) -">;-3,K
Dateadd(wk,datediff(wk,0,getdate()),6) AUG#_HE]k
就是表示本周时间段. [.7d<oY
下面的SQL的条件部分,就是查询时间段在本周范围内的: )4 e.k$X^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 'urafE4M
而在存储过程中 we//|fA<
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ^eY!U%.
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) cKca;SNql1