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^5Q
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一、基础 ),j6tq[
1、说明:创建数据库 bF+j%=
CREATE DATABASE database-name tw\1&*:
2、说明:删除数据库 \l
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drop database dbname g4 +Hq *
3、说明:备份sql server .ns=jp
--- 创建 备份数据的 device :^>&t^E
USE master u5KAwMw%Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Iij$ce`nx
--- 开始 备份 O2="'w'kR
BACKUP DATABASE pubs TO testBack ~ kDJ-V
4、说明:创建新表 D+~*nc ~
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) e5 zi "~
根据已有的表创建新表: ) vVf- zU
A:create table tab_new like tab_old (使用旧表创建新表) WQD:~*C:
B:create table tab_new as select col1,col2... from tab_old definition only 6uUn
5、说明:删除新表 Z*h}E
drop table tabname fZ;}_wR-H
6、说明:增加一个列 "^wIoJ6H'
Alter table tabname add column col type I,)\506
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 MLmaA3
7、说明:添加主键: Alter table tabname add primary key(col) 5a)$:oO!
说明:删除主键: Alter table tabname drop primary key(col) se=^K#o
8、说明:创建索引:create [unique] index idxname on tabname(col....) :h3n[%
删除索引:drop index idxname dZb;`DjTH
注:索引是不可更改的,想更改必须删除重新建。 5dD8s-;^T
9、说明:创建视图:create view viewname as select statement /<(-lbq,
删除视图:drop view viewname KHJ wCv
10、说明:几个简单的基本的sql语句 C=cn.CX
选择:select * from table1 where 范围 ]?oJxW.
插入:insert into table1(field1,field2) values(value1,value2) e-\/1N84
删除:delete from table1 where 范围 3MKu!
更新:update table1 set field1=value1 where 范围 ucU7
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! N`N?1!fM<}
排序:select * from table1 order by field1,field2 [desc] Zkqq<
总数:select count as totalcount from table1 ~
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求和:select sum(field1) as sumvalue from table1 h%4UeL &F
平均:select avg(field1) as avgvalue from table1 R(cg`8
最大:select max(field1) as maxvalue from table1 .c__T{<)[
最小:select min(field1) as minvalue from table1 d\JBjT1g
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11、说明:几个高级查询运算词 V
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A: UNION 运算符 "Ehh9 m1&
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。 KtH^k&z.f
B: EXCEPT 运算符 qK9A
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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%kEW%I yG
C: INTERSECT 运算符 'd&4MA 0X
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。 Ryxu#]s
注:使用运算词的几个查询结果行必须是一致的。 ;'08-Et
12、说明:使用外连接 k hD)x0'b
A、left outer join: g#7Q-n3^
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。 }&2,!;"">3
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 v9S=$Aj
B:right outer join: #Er"i
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 (uhE'IQ{(
C:full outer join: X7`-dSVE
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 vH1,As
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二、提升 )& Oxp&x
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Fav++ z
法一:select * into b from a where 1<>1 T:H~Y+qnt
法二:select top 0 * into b from a Iwh0PfWJ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4m"0R\
insert into b(a, b, c) select d,e,f from b; ) jvI Nb
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) hN]l
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 5;^1Ab0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {&B_b|g*fW
4、说明:子查询(表名1:a 表名2:b) 5;XYF0
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ED" fi$
5、说明:显示文章、提交人和最后回复时间 XuHR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Wi>m}^}9
6、说明:外连接查询(表名1:a 表名2:b) %N`_g' r!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c z9g6%RbwX
7、说明:在线视图查询(表名1:a ) fiD,HGx
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select * from (SELECT a,b,c FROM a) T where t.a > 1; B$x@I\(M
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 i'"#{4I
select * from table1 where time between time1 and time2 Rt&5s)O'
select a,b,c, from table1 where a not between 数值1 and 数值2 y@1QVt04
9、说明:in 的使用方法 .y3E@0a
select * from table1 where a [not] in ('值1','值2','值4','值6') 3;> z %{
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]j6K3
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )cZHBG.0H
11、说明:四表联查问题: .>.GQUr
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 ..... #=33TvprR2
12、说明:日程安排提前五分钟提醒 G +41D
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bj6Yz,g F
13、说明:一条sql 语句搞定数据库分页 }Bsh!3D<.
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 #)twk`!^
14、说明:前10条记录 X"r.*fb;N
select top 10 * form table1 where 范围 YZSQOLN{
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.) Ldv,(ZV,<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oSkQ/5hg.
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 bR~(Ry`
(select a from tableA ) except (select a from tableB) except (select a from tableC) _;Xlw{FN^
17、说明:随机取出10条数据 )z18:C3
select top 10 * from tablename order by newid() @U1|?~M%s
18、说明:随机选择记录 r=vY-p
select newid() 5$HG#2"Kb#
19、说明:删除重复记录 R9#ar{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ~_N,zw{x
20、说明:列出数据库里所有的表名 z>,M@@
select name from sysobjects where type='U'
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21、说明:列出表里的所有的 Y&U-d{"
select name from syscolumns where id=object_id('TableName') Haekr*1%
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ~_ZK93o(
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ge6S_"
显示结果: ?<
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type vender pcs ]sL.+.P
电脑 A 1 Y;huTZ
电脑 A 1 t!6uz
光盘 B 2 a=A12<
光盘 A 2 pI8z.JD
手机 B 3 Tj_K5uccU}
手机 C 3 UXdc'i g
23、说明:初始化表table1 Qj_)^3`e
TRUNCATE TABLE table1 x>TIx[x
24、说明:选择从10到15的记录 }5(_gYr
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Cb? !+U
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三、技巧 '/9j"mIA9$
1、1=1,1=2的使用,在SQL语句组合时用的较多 U:n~S
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?QJx!'Y,p
如: vN],9q
if @strWhere !='' f'(F'TE
begin 3'` &D/n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Y$n+\K
end r,0D I
else %aK[Yvo6
begin Xy 4k;+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' )V[j~uOU)]
end L
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我们可以直接写成 +pYwc0~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 0=6mb]VUi=
2、收缩数据库 1t &_]q_
--重建索引 g |?}a]G
DBCC REINDEX %%?}db1n
DBCC INDEXDEFRAG 0|tyKP|J
--收缩数据和日志 QK0]9
DBCC SHRINKDB R=E4Sh
DBCC SHRINKFILE WKlqm)m@
3、压缩数据库 2#lpIj
dbcc shrinkdatabase(dbname) g_P98_2f.k
4、转移数据库给新用户以已存在用户权限 y'odn ;
exec sp_change_users_login 'update_one','newname','oldname' <ml?DXT
go N~CQh=<
5、检查备份集 n/Fxjf0W
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e.DN,rhqI
6、修复数据库 #I0FWZ>W
ALTER DATABASE [dvbbs] SET SINGLE_USER 3?"gfw W
GO NcF>}f,}\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $3>Rw/,
GO %po;ih$jr*
ALTER DATABASE [dvbbs] SET MULTI_USER S}U_uZ$b
GO Y 'X!T8
7、日志清除 IO"P /Q
SET NOCOUNT ON ciml:"nQ
DECLARE @LogicalFileName sysname, wdBBx\FP
@MaxMinutes INT, a]V8F&)g#
@NewSize INT <@ ts[p.
USE tablename -- 要操作的数据库名 l:eC+[_;>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~zac.:a8
@MaxMinutes = 10, -- Limit on time allowed to wrap log. i*mU<:t
@NewSize = 1 -- 你想设定的日志文件的大小(M) kJf0..J[#<
-- Setup / initialize 8\'tfHL
DECLARE @OriginalSize int hOZTD0
SELECT @OriginalSize = size Eze w@*(
FROM sysfiles f:~G)
WHERE name = @LogicalFileName /N*<Fq7w~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Nh^I{%.x
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !9$}1_,is
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' db_?da;!`
FROM sysfiles Y_ne?/sZE
WHERE name = @LogicalFileName t855|
CREATE TABLE DummyTrans y|MhV/P04
(DummyColumn char (8000) not null) 4To$!=
DECLARE @Counter INT, e\[q3J
@StartTime DATETIME, b' M"To@
@TruncLog VARCHAR(255) 2INpo
SELECT @StartTime = GETDATE(), ,pTZ/#vP#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' W?4:sLC#3
DBCC SHRINKFILE (@LogicalFileName, @NewSize) YB 7A5
EXEC (@TruncLog) urx?p^c
-- Wrap the log if necessary. J9NuqV3
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #'%ii,;wQ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :'ZR!w
AND (@OriginalSize * 8 /1024) > @NewSize 3-:^mRPJ
BEGIN -- Outer loop. t/O^7)%
SELECT @Counter = 0 <>n|_6'$90
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,#,K_oz
BEGIN -- update RPeH [M^
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans N5 ; z5E
SELECT @Counter = @Counter + 1 {{P 3Z[
END ?_AX;z
EXEC (@TruncLog) '\8YH+%It
END ti9e(Jt!O
SELECT 'Final Size of ' + db_name() + ' LOG is ' + |-\anby<
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Y~^R^J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' dly -mPmP
FROM sysfiles G2!<C-T{2
WHERE name = @LogicalFileName jc:=Pe!E
DROP TABLE DummyTrans 4<1V
SET NOCOUNT OFF 1l^[%0
8、说明:更改某个表 t6-fG/Kc
exec sp_changeobjectowner 'tablename','dbo' SufM~9Ll
9、存储更改全部表 _[&.`jTFn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch G){+.X4g3
@OldOwner as NVARCHAR(128), 9CwtBil<#g
@NewOwner as NVARCHAR(128) M{)eA<6
AS A\7sP =
DECLARE @Name as NVARCHAR(128) _f>)G3p
DECLARE @Owner as NVARCHAR(128) .@;5"
DECLARE @OwnerName as NVARCHAR(128) TZ
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DECLARE curObject CURSOR FOR 751Qi
select 'Name' = name, $1s>efP-
'Owner' = user_name(uid) HXdo:#xEO
from sysobjects /u]#dX5
where user_name(uid)=@OldOwner =$^}"}$
order by name
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OPEN curObject ZK2&l8
FETCH NEXT FROM curObject INTO @Name, @Owner Fpn'0&~-fi
WHILE(@@FETCH_STATUS=0) J]S6%omp>
BEGIN oLlfqV,|L\
if @Owner=@OldOwner ]1GyEr:
begin rB(Q)N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 4UW)XLu6T7
exec sp_changeobjectowner @OwnerName, @NewOwner dn=srbJ
end 86qQ"=v
-- select @name,@NewOwner,@OldOwner dn42'(p@G
FETCH NEXT FROM curObject INTO @Name, @Owner $'!n4}$}
END ;&?ITV
close curObject i,Jz7OX
deallocate curObject (A}c22qe
GO I-J%yutB
10、SQL SERVER中直接循环写入数据 EXW?)_pg
declare @i int Ty!V)i
set @i=1 J-
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while @i<30 2.{<C.BK{
begin "<&o;x<
insert into test (userid) values(@i) #sv}%oV,F
set @i=@i+1 l_2l/ff9
end L4u.cHJ}0
小记存储过程中经常用到的本周,本月,本年函数 -s0J8b
Dateadd(wk,datediff(wk,0,getdate()),-1) /
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Dateadd(wk,datediff(wk,0,getdate()),6) @LU[po1I
Dateadd(mm,datediff(mm,0,getdate()),0) ~Lu,jLKL=[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) e+2lus,u6t
Dateadd(yy,datediff(yy,0,getdate()),0) @\-*aS_8>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0T$ `;~
上面的SQL代码只是一个时间段 \b)P4aL
Dateadd(wk,datediff(wk,0,getdate()),-1) q9^.f9-
Dateadd(wk,datediff(wk,0,getdate()),6) <0l:B;3
就是表示本周时间段. 8)`
下面的SQL的条件部分,就是查询时间段在本周范围内的: b-c6.aKf|
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) h"2^`
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而在存储过程中 JiA1yt
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >:
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) kY4h-oZ