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。 `n7z+
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一、基础 'Z-jj2t}
1、说明:创建数据库 G1Cn[F;e
CREATE DATABASE database-name }0T1* .Cz
2、说明:删除数据库 i+&*W{Re
drop database dbname =@m|g )
3、说明:备份sql server .h^."+TJ
--- 创建 备份数据的 device -O_5OT4
USE master x~}RL-Y2o
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?0+D1w
--- 开始 备份 er}/~@JJ
BACKUP DATABASE pubs TO testBack 1dOVH7
4、说明:创建新表 ]7ROCJ;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) u|\Lb2Kb:
根据已有的表创建新表: _.Y?BAQ
A:create table tab_new like tab_old (使用旧表创建新表) ~)}npS;
B:create table tab_new as select col1,col2... from tab_old definition only D:llGdU#2
5、说明:删除新表 j]6j!.1
drop table tabname ocy fU=}X
6、说明:增加一个列 ~l-Q0wg
Alter table tabname add column col type "}|n;:r
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。 Hq^sU%
7、说明:添加主键: Alter table tabname add primary key(col) r9G<HKl
说明:删除主键: Alter table tabname drop primary key(col) J;+iW*E:
8、说明:创建索引:create [unique] index idxname on tabname(col....) &|H?J,>
删除索引:drop index idxname V2%FWo|
注:索引是不可更改的,想更改必须删除重新建。 W\zg#5fmK
9、说明:创建视图:create view viewname as select statement X#(?V[F]
删除视图:drop view viewname x<"e} Oo
10、说明:几个简单的基本的sql语句 &@A(8(%
选择:select * from table1 where 范围 dapQ5JT/
插入:insert into table1(field1,field2) values(value1,value2) {y'c*NS
删除:delete from table1 where 范围 8|?$KLz?F>
更新:update table1 set field1=value1 where 范围 G7`7e@{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \<~[uv'
排序:select * from table1 order by field1,field2 [desc] Q5iuK#/
总数:select count as totalcount from table1 `w]=xe
求和:select sum(field1) as sumvalue from table1 &`<j!xlG
平均:select avg(field1) as avgvalue from table1 8(D>ws$
最大:select max(field1) as maxvalue from table1 w@4q D
最小:select min(field1) as minvalue from table1 uA:|#mO
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11、说明:几个高级查询运算词 CO1D.5
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A: UNION 运算符 o8RagSIo8
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。 '>Y"s|
B: EXCEPT 运算符 NZ'S~Lr
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。 ~jmHzFkQ
C: INTERSECT 运算符 ld4QhZia
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。 I1
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注:使用运算词的几个查询结果行必须是一致的。 xe2Ap[Y'M
12、说明:使用外连接 _;{n+i[
A、left outer join: (D{Fln\
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。 k#E D#']N
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 Q! ]
B:right outer join: v-X1if1%
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。 (H<S&5[
C:full outer join: ;p/RS#
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。 G1vWHa7n;f
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二、提升 Z=
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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) Txfu%'2)e
法一:select * into b from a where 1<>1 WtFv"$V
法二:select top 0 * into b from a Io{)@H"f
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
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insert into b(a, b, c) select d,e,f from b; W j/.rG&tE
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) $k V^[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 KDuM;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "N"9PTX
4、说明:子查询(表名1:a 表名2:b) ]0zXpMNI
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) ?z171X0
5、说明:显示文章、提交人和最后回复时间 GNqw]@'Yf
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~9p*zC3M
6、说明:外连接查询(表名1:a 表名2:b) 'AE)&56
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c %:N6#;l M
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; q*\#HC
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 uv}[MXOP
select * from table1 where time between time1 and time2 ,+KZn}>
select a,b,c, from table1 where a not between 数值1 and 数值2 7Nw7a;h
9、说明:in 的使用方法 ;-lk#D?n9
select * from table1 where a [not] in ('值1','值2','值4','值6') +L!-JrYHS4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 UW<V(6P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) qXkc~{W_
11、说明:四表联查问题: HjbC>*
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 ..... /fWVgyW>6
12、说明:日程安排提前五分钟提醒 k ;R*mg*K
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Ti!j
13、说明:一条sql 语句搞定数据库分页 D!ToCVos
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 /);cl;"
14、说明:前10条记录 f:G Zb?Wyd
select top 10 * form table1 where 范围 /,f*IdB
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.) DHW;*A-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) DT8|2"H
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 `)&-;CMY
(select a from tableA ) except (select a from tableB) except (select a from tableC) ddmTMfH
17、说明:随机取出10条数据 z"u4t.KpL
select top 10 * from tablename order by newid() Q_euNoA0
18、说明:随机选择记录 vAbMU
select newid() =GTltFqI1
19、说明:删除重复记录 ;M{ @23?`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) :kfHILi
20、说明:列出数据库里所有的表名 gXZ.je)NM
select name from sysobjects where type='U' bBc<yaN
21、说明:列出表里的所有的 0R>M_|
select name from syscolumns where id=object_id('TableName') 4iBp!k7
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。 *T*=~Y4kE
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 +#}I^N
显示结果: :seo0w]
type vender pcs cXFNX<
电脑 A 1 =LL5E}xP
电脑 A 1 &7!&]kA+
光盘 B 2 Pk7Yq:avL
光盘 A 2 O7I:Y85i#O
手机 B 3 0PIC|
手机 C 3 E9;cd$}K
23、说明:初始化表table1 ns9iTU)
TRUNCATE TABLE table1 znw\Dn?g
24、说明:选择从10到15的记录 @Nn9-#iW
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Qa~o'
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三、技巧 9w^1/t&=04
1、1=1,1=2的使用,在SQL语句组合时用的较多 M2(+}gv;7p
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $(H%|Oyn
如: <->Nex
if @strWhere !='' Q9H~B`\nQ
begin qYBoo]}a
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X#j-Ld{j
end Wjn1W;m&g
else >c*}Do{lG
begin !s06uh
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' v}!eJzeH
end >t&Frw/Bl
我们可以直接写成 `$\g8Mo
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \Y_2Z/
2、收缩数据库 FN NEh
--重建索引 1@6dHFA`o
DBCC REINDEX UB }n=
DBCC INDEXDEFRAG v=E V5#A
--收缩数据和日志
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DBCC SHRINKDB 8bLA6qmM\
DBCC SHRINKFILE cu5Yvp
3、压缩数据库 "jH=O(37
dbcc shrinkdatabase(dbname) OW-[#r
4、转移数据库给新用户以已存在用户权限 1-r#v
exec sp_change_users_login 'update_one','newname','oldname' L!Iu\_{q
go .p NWd
5、检查备份集 Fd*)1FQKT
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <[ />M
6、修复数据库 :^tw!U%y1
ALTER DATABASE [dvbbs] SET SINGLE_USER j-8v$0'
GO M>VT$!Lx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK SCs@Q
GO T3,"g=
ALTER DATABASE [dvbbs] SET MULTI_USER 2`tdH|Z`
GO "5"6mw?
7、日志清除 Xp@8vu
SET NOCOUNT ON A9'
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DECLARE @LogicalFileName sysname, @,F8gv*
@MaxMinutes INT, l)<
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@NewSize INT IugYlt
USE tablename -- 要操作的数据库名 W+-a@)sh3Q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 GoP,_sd\O
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~F [}*%iR
@NewSize = 1 -- 你想设定的日志文件的大小(M) Kq@n BkO4
-- Setup / initialize Gx
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DECLARE @OriginalSize int zZ&L#
SELECT @OriginalSize = size D1o<:jOj
FROM sysfiles k
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WHERE name = @LogicalFileName o^hI\9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + REUWK#>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + wYQTG*&h
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' mr
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FROM sysfiles y! he<4
WHERE name = @LogicalFileName r|wB&
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CREATE TABLE DummyTrans Q?-HU,RBO
(DummyColumn char (8000) not null) -Zx
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DECLARE @Counter INT, 64;F g/t
@StartTime DATETIME, L1A0->t
@TruncLog VARCHAR(255) ?muI8b
SELECT @StartTime = GETDATE(), \g<9_
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1ThONrxu
DBCC SHRINKFILE (@LogicalFileName, @NewSize) GxE"q-G
EXEC (@TruncLog) X~ |P
-- Wrap the log if necessary. @ FVan
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~WXT0-,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~CiVLSH=
AND (@OriginalSize * 8 /1024) > @NewSize }`#OA]NZ
BEGIN -- Outer loop. /nEt%YYh;x
SELECT @Counter = 0 =!u9]3)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |g<1n
BEGIN -- update >Pne@w!*
INSERT DummyTrans VALUES ('Fill Log') Tap=K|b ]
DELETE DummyTrans 5[l9`Cn&A
SELECT @Counter = @Counter + 1 BayO+,>K
END iJ.P&T9
EXEC (@TruncLog) v$c*3H.seM
END CBw/a0Uck
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ylbh_ d~BU
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + rvO7e cR"
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ?&$??r^i
FROM sysfiles H%N!;Jz=
WHERE name = @LogicalFileName L".Qf|b*
DROP TABLE DummyTrans ;d$PQi
SET NOCOUNT OFF )D\cm7WX^[
8、说明:更改某个表 +p6cG\Gp
exec sp_changeobjectowner 'tablename','dbo' <Wc98m
9、存储更改全部表 w{uqy]
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch c4QegN
@OldOwner as NVARCHAR(128), @i'24Q[6
@NewOwner as NVARCHAR(128) b<,Z^Z_
AS i(DoAfYf/q
DECLARE @Name as NVARCHAR(128) &'`q&U1x
DECLARE @Owner as NVARCHAR(128) ~Wy&xs ZH
DECLARE @OwnerName as NVARCHAR(128) UB[tYZ
DECLARE curObject CURSOR FOR [U+6Tj,
select 'Name' = name, fy|ycWW>8
'Owner' = user_name(uid) ^Q!qJav
from sysobjects 3`sM/BoA
where user_name(uid)=@OldOwner /3|uU
order by name wq&|V
OPEN curObject [pMJ9
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FETCH NEXT FROM curObject INTO @Name, @Owner xbJ@ z{
WHILE(@@FETCH_STATUS=0) `H+~LVH
BEGIN _22;hnG<iy
if @Owner=@OldOwner <hlH@[7!
begin )=VSERs
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $nN`K*%
exec sp_changeobjectowner @OwnerName, @NewOwner Eq$Q%'5*ua
end R^zTgyr
-- select @name,@NewOwner,@OldOwner ]jo^P5\h>
FETCH NEXT FROM curObject INTO @Name, @Owner 1(!w xJ
END &4M0 S+.
close curObject ?DPNa
deallocate curObject VsS.\1
GO :NB|r
10、SQL SERVER中直接循环写入数据 i!
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declare @i int vt{s"\f
set @i=1 (I3:u-A
while @i<30 V9xZH5T8^
begin |rJ1/T.9
insert into test (userid) values(@i) TAz#e
set @i=@i+1 (?MRbX]@
end &1O[N*$e
小记存储过程中经常用到的本周,本月,本年函数 Abr:UEG
Dateadd(wk,datediff(wk,0,getdate()),-1) 4k'2FkDA
Dateadd(wk,datediff(wk,0,getdate()),6) hgCF!eud
Dateadd(mm,datediff(mm,0,getdate()),0) tBEZ4 W>67
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) A:Y]<jt
Dateadd(yy,datediff(yy,0,getdate()),0) uv*OiB"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) "0Xa?z8"
上面的SQL代码只是一个时间段 @91Q=S
Dateadd(wk,datediff(wk,0,getdate()),-1) #6g-{OBv
Dateadd(wk,datediff(wk,0,getdate()),6) :`BZ,j_
就是表示本周时间段. b_88o-*/
下面的SQL的条件部分,就是查询时间段在本周范围内的: Kj[X1X5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &.k'Dj2hf
而在存储过程中 |~mq+:44+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (WT0j
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) }W&hPC