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。 ^sH1YE}0
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一、基础 {U=za1Ga
1、说明:创建数据库 uXeB OLC
CREATE DATABASE database-name j^ZpBN L
2、说明:删除数据库 r jU $*+
drop database dbname $y=sT({VVe
3、说明:备份sql server X4i$,$C
--- 创建 备份数据的 device N|q:wyS|
USE master vzaxi;S<
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' fE)+9!
--- 开始 备份 s4SR6hBO
BACKUP DATABASE pubs TO testBack ]8YHA}P
4、说明:创建新表 #.}Su+XF
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) l)VMF44
根据已有的表创建新表: ]@ETQ8QN
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only 4E3HYZ
5、说明:删除新表 1`_Mc ]
drop table tabname f%*-PW^*
6、说明:增加一个列 aI|)m8>)X
Alter table tabname add column col type A@'):V8_%C
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 C bG"8F|4
7、说明:添加主键: Alter table tabname add primary key(col) [.z1
说明:删除主键: Alter table tabname drop primary key(col) #f/-i u=L
8、说明:创建索引:create [unique] index idxname on tabname(col....) aqs']
删除索引:drop index idxname Q8Usyc'3
注:索引是不可更改的,想更改必须删除重新建。 F>A-+]X3o
9、说明:创建视图:create view viewname as select statement IG +nrTY0
删除视图:drop view viewname }SpMHR`
10、说明:几个简单的基本的sql语句 ?Pmj }f
选择:select * from table1 where 范围 iCk34C7
插入:insert into table1(field1,field2) values(value1,value2) @oYq.baHX
删除:delete from table1 where 范围 n2,b~S\e
更新:update table1 set field1=value1 where 范围 L6$,<}l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1Sz5&jz
排序:select * from table1 order by field1,field2 [desc] >!? f6
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总数:select count as totalcount from table1 P9`i6H'~
求和:select sum(field1) as sumvalue from table1 ~`tc|Zu
平均:select avg(field1) as avgvalue from table1 k1-?2kf"{
最大:select max(field1) as maxvalue from table1 ?\hXJih
最小:select min(field1) as minvalue from table1 B5B'H3@
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11、说明:几个高级查询运算词 Mw'd<{
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A: UNION 运算符 Ev0V\tl>0
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。 =NJb9S&8A
B: EXCEPT 运算符 3CQpe
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。 @292;qi
C: INTERSECT 运算符 6t]oSxN
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。 zCvR/
注:使用运算词的几个查询结果行必须是一致的。 m/Yi;>I(
12、说明:使用外连接 'zT/x`V
A、left outer join: GUat~[lUrj
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。 |Z 3POD"9
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 8agd{bxU
B:right outer join: AW> P\>{RE
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。 NV9= ~cx
C:full outer join: C
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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。 *+p'CfsSka
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二、提升
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _IpW&
法一:select * into b from a where 1<>1 (2qo9j"j/Y
法二:select top 0 * into b from a HTx7._b
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o]Vx6
insert into b(a, b, c) select d,e,f from b; >+oQxml6nI
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) ?wwY8e?S
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fXL>L
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. l@#X]3h!
4、说明:子查询(表名1:a 表名2:b) NJl|/(]v
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) :^iR&`2~
5、说明:显示文章、提交人和最后回复时间 sOJ"~p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -QS_bQG%
6、说明:外连接查询(表名1:a 表名2:b) ,rX!V=Z5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <Bu*: O
7、说明:在线视图查询(表名1:a ) $$qhX]^~
select * from (SELECT a,b,c FROM a) T where t.a > 1; J)g(Nw,O
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 _5y)m5I
select * from table1 where time between time1 and time2 PrN?;Z.
select a,b,c, from table1 where a not between 数值1 and 数值2 yx/:<^"-$
9、说明:in 的使用方法 NmtBn^t
select * from table1 where a [not] in ('值1','值2','值4','值6') %8{' XJ!
10、说明:两张关联表,删除主表中已经在副表中没有的信息 yY_]YeeR
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =~aJ]T}(
11、说明:四表联查问题: ?# 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 ..... RI*Q-n{
12、说明:日程安排提前五分钟提醒 2! wz#EC
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 3U:0 ,-j"
13、说明:一条sql 语句搞定数据库分页 [BV{=;iD
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 SxT:k,ji
14、说明:前10条记录 Wdy2;a<\{
select top 10 * form table1 where 范围 SZwfYY!ft0
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.) 0W=IuPDU
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c yN_Sg
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 5jjJQ'
(select a from tableA ) except (select a from tableB) except (select a from tableC) >)S
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17、说明:随机取出10条数据 ]Uxx_1$,
select top 10 * from tablename order by newid() 23+GX&Rp
18、说明:随机选择记录 b|fq63ar;
select newid() XTeU2I
19、说明:删除重复记录 I|R9@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \-sDRW
20、说明:列出数据库里所有的表名 $~ItT1k_
select name from sysobjects where type='U' i!czI8
21、说明:列出表里的所有的 80+"
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select name from syscolumns where id=object_id('TableName') W
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 g?@(+\W
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Z.R^@@RqJ
显示结果: <,cD EN7
type vender pcs 8@$QN4^u^
电脑 A 1 $rjv4e}7
电脑 A 1 @[JQCQ#r
光盘 B 2 D% 50
光盘 A 2 n7{c0;)$
手机 B 3 {ZfTUt)-P
手机 C 3 <w,aS;v6jp
23、说明:初始化表table1 +qS$t
TRUNCATE TABLE table1 $W0lz#s:
24、说明:选择从10到15的记录 Jn:GqO
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Y,&)%Eo<
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三、技巧 14^t{
1、1=1,1=2的使用,在SQL语句组合时用的较多 o^AK@\e:^Z
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \j K?R
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如: cCj}{=U
if @strWhere !='' 8H{@0_M
begin m$O@+;>l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .+M4Pi
end u(REEc~nj
else +*|E%pq
begin ?SQT;C3j(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' cxmr|-^
end 4`*jF'N[
我们可以直接写成 bTn-Pg){
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere K, 35*
2、收缩数据库 EI f~>AI
--重建索引 ("9)=x *5
DBCC REINDEX o\2#}eie
DBCC INDEXDEFRAG Ajq<=y`NzV
--收缩数据和日志 ) I5f`r=Ry
DBCC SHRINKDB a{)"KA P
DBCC SHRINKFILE ]7br*t^zv
3、压缩数据库 #~ >0Dr
dbcc shrinkdatabase(dbname) ?. ~@ lE
4、转移数据库给新用户以已存在用户权限 3[ Z? `X
exec sp_change_users_login 'update_one','newname','oldname' / ?Q@Pn
go U1&m-K
5、检查备份集 AalyEn&>
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' pWQ?pTh
6、修复数据库 q=6M3OnS>
ALTER DATABASE [dvbbs] SET SINGLE_USER ~w!<J-z)
GO X#Hs{J~@p
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK kszYbz "
GO 9vVYZ}HC
ALTER DATABASE [dvbbs] SET MULTI_USER -aec1+o
GO 46$5f?Z
7、日志清除 `Y'}\>.#
SET NOCOUNT ON $aVcWz%
DECLARE @LogicalFileName sysname, UHxXa*HyI
@MaxMinutes INT, GadD*psD2
@NewSize INT oFY'Ek;d
USE tablename -- 要操作的数据库名 0gnr@9,X
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ?N`W,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]i{-@Ven
@NewSize = 1 -- 你想设定的日志文件的大小(M) [z Y9"B<3
-- Setup / initialize ;%Z)$+Z_)<
DECLARE @OriginalSize int 3 i>uKU1
SELECT @OriginalSize = size LdRLKE<'e
FROM sysfiles ="XxS|Mq3
WHERE name = @LogicalFileName Q+#, VuM
SELECT 'Original Size of ' + db_name() + ' LOG is ' + G:A`
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + uS<&$JH
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' X\flx~
FROM sysfiles JZai{0se
WHERE name = @LogicalFileName 9v/1>rziE
CREATE TABLE DummyTrans m@TU2
(DummyColumn char (8000) not null) eLl;M4d
DECLARE @Counter INT, RX#:27:
@StartTime DATETIME, 3ne=7Mj
@TruncLog VARCHAR(255) )kg^.tP
SELECT @StartTime = GETDATE(), r_Xk:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' t&-7AjS5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [,lBY-Kz+
EXEC (@TruncLog) ! 5 ]/2
-- Wrap the log if necessary. ]Wfnpqc^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired X4 xnr^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) `@eQL[Z9x
AND (@OriginalSize * 8 /1024) > @NewSize [x9eamJ,H
BEGIN -- Outer loop. 539[,jH
SELECT @Counter = 0 ga!t:O@w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C'hZNFsF;
BEGIN -- update G;`+MgJ)
INSERT DummyTrans VALUES ('Fill Log') |nv8&L8
DELETE DummyTrans 5J1,Usm
SELECT @Counter = @Counter + 1 tX6n~NJ$
END <sn^>5Ds
EXEC (@TruncLog) $,bLb5}Qu
END *y u|]T
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hfVJg7-
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9D-PmSnv
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' `43E-'g
FROM sysfiles \vpUl
WHERE name = @LogicalFileName (LQ*U3J]_
DROP TABLE DummyTrans !.kj-==s{7
SET NOCOUNT OFF _PQQ&e)E
8、说明:更改某个表 F DXAe-|Q
exec sp_changeobjectowner 'tablename','dbo' 0(HUy`]>
9、存储更改全部表 0riTav8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _sx]`3/86
@OldOwner as NVARCHAR(128), $Z$BF
@NewOwner as NVARCHAR(128) Br;1kQ%e C
AS yA=#Ji
DECLARE @Name as NVARCHAR(128) rr9N(AoxW
DECLARE @Owner as NVARCHAR(128) bm`x
DECLARE @OwnerName as NVARCHAR(128) U H
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DECLARE curObject CURSOR FOR }zj_Pp
select 'Name' = name, ?3"lI,!0
'Owner' = user_name(uid) rVkRU5
from sysobjects sF f@>
where user_name(uid)=@OldOwner lg~Gkd6
order by name -PoW56
OPEN curObject _-^a8F>/19
FETCH NEXT FROM curObject INTO @Name, @Owner qgDd^0
WHILE(@@FETCH_STATUS=0) j%Usui<DL
BEGIN +<&_1%5+
if @Owner=@OldOwner g \&Z_
begin `l'z#\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <Zn]L:
exec sp_changeobjectowner @OwnerName, @NewOwner b-\ 1D;]
end 2w+w'Ag_R
-- select @name,@NewOwner,@OldOwner G[ @RZ~o4
FETCH NEXT FROM curObject INTO @Name, @Owner <V>]-bl/
END 4Zo.c*
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close curObject B[epI3R
deallocate curObject Y'mtMLfMc
GO =g
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10、SQL SERVER中直接循环写入数据 RGf&KV/
declare @i int RG0kOw0
set @i=1 -LhO
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while @i<30 J<yt/V]
begin o7;lR?
insert into test (userid) values(@i) lvY[E9I0
set @i=@i+1 X0.k Q
end +<a-;e{
小记存储过程中经常用到的本周,本月,本年函数 P XKEqcQR
Dateadd(wk,datediff(wk,0,getdate()),-1) l1l=52r
Dateadd(wk,datediff(wk,0,getdate()),6) jEVDz
Dateadd(mm,datediff(mm,0,getdate()),0) g1Ed:V]_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) -U.>K,M
Dateadd(yy,datediff(yy,0,getdate()),0) Qzt'ZK
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~}pc&jz>q
上面的SQL代码只是一个时间段 _Dr9 w&;<
Dateadd(wk,datediff(wk,0,getdate()),-1) 8BE] A_X
Dateadd(wk,datediff(wk,0,getdate()),6) nl5A{ s
就是表示本周时间段. ,)@njC?J
下面的SQL的条件部分,就是查询时间段在本周范围内的: +saXN6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ;-#2p^
而在存储过程中 G5vp(%j
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) FUzN}"\1
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) t-B5,,`