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。 )3<|<jwcx
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一、基础 8<(qN>R
1、说明:创建数据库 E~?0Yrm F
CREATE DATABASE database-name "dfq
2、说明:删除数据库 "p>$^
drop database dbname NNZ%jJy?=,
3、说明:备份sql server ":E^&yQ
--- 创建 备份数据的 device m+p}Qi8i)
USE master \u@4eBAV
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [(v?Z`cX\
--- 开始 备份 %2Q:+6)
BACKUP DATABASE pubs TO testBack =;DmD?nZ
4、说明:创建新表 2XhtK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sg"J00
根据已有的表创建新表: }:u" ?v=|j
A:create table tab_new like tab_old (使用旧表创建新表) xW@y=l Cu
B:create table tab_new as select col1,col2... from tab_old definition only `ER">@&
5、说明:删除新表 0yW#).D^b
drop table tabname n:JWu0,h
6、说明:增加一个列 cW B>
Alter table tabname add column col type m1@ste;$W
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。 dz
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7、说明:添加主键: Alter table tabname add primary key(col) f8`K8Y]4
说明:删除主键: Alter table tabname drop primary key(col) ^lVZW8
8、说明:创建索引:create [unique] index idxname on tabname(col....) @y%4BU&>0
删除索引:drop index idxname n4Fh*d ixg
注:索引是不可更改的,想更改必须删除重新建。 8A/;a{
9、说明:创建视图:create view viewname as select statement Wyu$J
删除视图:drop view viewname R?"sM<3`e
10、说明:几个简单的基本的sql语句 }7iWm XlI
选择:select * from table1 where 范围 PI{;3X}9$,
插入:insert into table1(field1,field2) values(value1,value2) ;J|sH>i
删除:delete from table1 where 范围 JmDi{B?
更新:update table1 set field1=value1 where 范围 9(?9yFbj5
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Cz=HxU80J
排序:select * from table1 order by field1,field2 [desc] E$5)]<p! <
总数:select count as totalcount from table1 dQ6:c7hp>D
求和:select sum(field1) as sumvalue from table1 >ZMB}pt`
平均:select avg(field1) as avgvalue from table1 4;anoqiG\
最大:select max(field1) as maxvalue from table1 W.OcmA>x
最小:select min(field1) as minvalue from table1 AR9D;YfR~
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11、说明:几个高级查询运算词 4yhan/zA
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A: UNION 运算符 4]L5%=atn
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 N@D]Q&;+(T
B: EXCEPT 运算符 8S2sNpLi-g
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 b-pZrnZ!
C: INTERSECT 运算符 '6l4MR$j&m
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。 ^z&eD,
注:使用运算词的几个查询结果行必须是一致的。 -2NXQ+m ;
12、说明:使用外连接 SMHQo/c r
A、left outer join: hdky:2^3
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。 [J0f:&7\
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 nY(>|!
B:right outer join: F?!P7 zW
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。 yWI30hW
C:full outer join: Vfkm{*t)
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。 9>gxJ7pY
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二、提升 /.1c<!
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e>yPFXSk
法一:select * into b from a where 1<>1 W\mj?R
法二:select top 0 * into b from a RL Beti>
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) tHF-OarUO
insert into b(a, b, c) select d,e,f from b; YbaaX{7^
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) r)Q/YzXx*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Dq=&K,5;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. a1p Z{Od
4、说明:子查询(表名1:a 表名2:b) WXJEAje
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) @qP
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5、说明:显示文章、提交人和最后回复时间 y $,K^f
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0#\K9|.
6、说明:外连接查询(表名1:a 表名2:b) K%NNw7\A
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l&rS\TCkp
7、说明:在线视图查询(表名1:a ) +tsF.Is!t
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5^kLNNum
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Ziclw)
select * from table1 where time between time1 and time2 O~3<P3W
select a,b,c, from table1 where a not between 数值1 and 数值2 !O;su~7
9、说明:in 的使用方法 6T-h("t
select * from table1 where a [not] in ('值1','值2','值4','值6') m|K"I3W$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ;#'YO1`gf3
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _+c' z
11、说明:四表联查问题: Hzm<KQ
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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 ..... M::
12、说明:日程安排提前五分钟提醒 9W^sq<tR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 'p%aHK{
13、说明:一条sql 语句搞定数据库分页 QaAA@l
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 jb0wP01R
14、说明:前10条记录 s
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select top 10 * form table1 where 范围 ^HS;\8Xvb
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.) --S1p0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) qp#Is{=m
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 ;Fo%R$y
(select a from tableA ) except (select a from tableB) except (select a from tableC) "LwLTPC2
17、说明:随机取出10条数据 n6A N
select top 10 * from tablename order by newid() KGM9
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18、说明:随机选择记录 _H{6{!=y
select newid() @;\2 PD
19、说明:删除重复记录 qq
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) u{|
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20、说明:列出数据库里所有的表名 e>F i
select name from sysobjects where type='U' aPU.fER
21、说明:列出表里的所有的 %@L[=\
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select name from syscolumns where id=object_id('TableName') .[8!
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 }-Ds%L
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 9Wu c1#
显示结果: ON(OYXj
type vender pcs t`M4@1S"'
电脑 A 1 GG0H3MSc
电脑 A 1 `!Z0;qk
光盘 B 2 ;s*
光盘 A 2 >m$jJlAv8
手机 B 3
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手机 C 3 !+UU[uM
23、说明:初始化表table1 8+f{ /
TRUNCATE TABLE table1 pwF+ZNo
24、说明:选择从10到15的记录 uOQ!av2"Rf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 64LX[8Ax#
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三、技巧 Fe[)-_%G
1、1=1,1=2的使用,在SQL语句组合时用的较多 qw?Wi%t(x8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @d&JtA
如: IZ/PZ"n_(
if @strWhere !='' [X9T$7q#
begin 58S qB
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |D% O`[k+
end VGYx(
else \DiAfx<Ub
begin eS`ZC!W
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' m/e*P*\=
end +Rj8"p$K
我们可以直接写成 *M? [Gro/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere =ea'G>;[H
2、收缩数据库 70GwTK.{~
--重建索引 %jE0Z4\
DBCC REINDEX &ir|2"HV
DBCC INDEXDEFRAG I[6ft_*
--收缩数据和日志 dEhFuNO<2
DBCC SHRINKDB +C}s"qrb@
DBCC SHRINKFILE :@RX}rKG
3、压缩数据库 dc dVB>D
dbcc shrinkdatabase(dbname) f`s.|99Y
4、转移数据库给新用户以已存在用户权限 D03QisH=
exec sp_change_users_login 'update_one','newname','oldname' XtZeT~/7RT
go q)l1tC72
5、检查备份集 u?F^gIw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Z=m5V (9
6、修复数据库 aD&4C-,1
ALTER DATABASE [dvbbs] SET SINGLE_USER WK.K-bd
GO ~} 02q5H
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK N79?s)l:K
GO w)Xn MyD(P
ALTER DATABASE [dvbbs] SET MULTI_USER dEI]|i
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GO dHkI9;
7、日志清除 dw-o71(1d
SET NOCOUNT ON rQ-,mq
DECLARE @LogicalFileName sysname, fB)S: f|
@MaxMinutes INT, z41v5rB4
@NewSize INT ]PlLy:(
USE tablename -- 要操作的数据库名 <74r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 OJ1MV 7&
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9'=ZxV
@NewSize = 1 -- 你想设定的日志文件的大小(M) K]'t>:G@
-- Setup / initialize [#SiwhF|
DECLARE @OriginalSize int m@y<wk(
SELECT @OriginalSize = size ;lQ>>[*
FROM sysfiles !{?<(6;t
WHERE name = @LogicalFileName +,_%9v?3
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 7.*Mmx~]=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &u4;A[-R
FROM sysfiles #=T^XHjQ
WHERE name = @LogicalFileName #0f6X,3
CREATE TABLE DummyTrans 2xBYJoF(
(DummyColumn char (8000) not null) U;=1v:~d
DECLARE @Counter INT, <2e[; $
@StartTime DATETIME, eUKl(
@TruncLog VARCHAR(255) g_JSgH!4
SELECT @StartTime = GETDATE(), Ie[DTy
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [7\x(W-:@>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 2BO&OX|X
EXEC (@TruncLog) vawS5b;
-- Wrap the log if necessary. _/J`v`}G
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =PjxMC._
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) h-]c
AND (@OriginalSize * 8 /1024) > @NewSize `n"PHur
BEGIN -- Outer loop. i~LY
SELECT @Counter = 0 $=5kn>[_Z%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) GvBmh .
BEGIN -- update `|<? sjY
INSERT DummyTrans VALUES ('Fill Log') d5"rCd[
DELETE DummyTrans MJA;P7g
SELECT @Counter = @Counter + 1 25;(`Td5
END 2Z-QVwa*U
EXEC (@TruncLog) 3*E]
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END PDS?>Jg(
SELECT 'Final Size of ' + db_name() + ' LOG is ' + cEIs9;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + c5Hyja=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' TSH'OW !b
FROM sysfiles X.V4YmZ-;
WHERE name = @LogicalFileName #fDM{f0]R
DROP TABLE DummyTrans B%WkM\\!^
SET NOCOUNT OFF lf\^!E:
8、说明:更改某个表 G8.nKoHv7x
exec sp_changeobjectowner 'tablename','dbo' G0h e'BR
9、存储更改全部表 tHEZuoi
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch I9<%fv
@OldOwner as NVARCHAR(128), @V Sr'?7-
@NewOwner as NVARCHAR(128) :_h#A}8Xd
AS Ek60[a
DECLARE @Name as NVARCHAR(128) q<K/q"0-l
DECLARE @Owner as NVARCHAR(128) k3T374t1b
DECLARE @OwnerName as NVARCHAR(128) (3 Z;c_N
DECLARE curObject CURSOR FOR !xU[BCbfYV
select 'Name' = name, lV9
'Owner' = user_name(uid) Svdmg D!
from sysobjects >=86*U~
where user_name(uid)=@OldOwner _K B%g_{
order by name ;?v&=Z't.
OPEN curObject %Iiu#- 'B
FETCH NEXT FROM curObject INTO @Name, @Owner buDz]ec
b
WHILE(@@FETCH_STATUS=0) S4pEBbV^n
BEGIN *=P*b|P"$
if @Owner=@OldOwner * ).YU[i
begin y@r0"cvz9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) J$d']%Dwb
exec sp_changeobjectowner @OwnerName, @NewOwner !AG {`[b
end fVJWW):
-- select @name,@NewOwner,@OldOwner "8Lv
FETCH NEXT FROM curObject INTO @Name, @Owner rN,T}M=2
END =y=MljEX
close curObject &(m01
deallocate curObject Hp*N%
GO dl(!{tZ#
10、SQL SERVER中直接循环写入数据 6#Rco%07zI
declare @i int RIDl4c
[
set @i=1 C#B|^A_
while @i<30 R\-]$\1D
begin *-S?bv,T'
insert into test (userid) values(@i) TkVqv v
set @i=@i+1 :%h|i&B
end e@1A_q@.
小记存储过程中经常用到的本周,本月,本年函数 A1*\ \[
Dateadd(wk,datediff(wk,0,getdate()),-1) '>HLE) l
Dateadd(wk,datediff(wk,0,getdate()),6) 7nsovWp
Dateadd(mm,datediff(mm,0,getdate()),0) P-DW@drxF
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Tv9\`F[
Dateadd(yy,datediff(yy,0,getdate()),0) tO?-@Qf/9<
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) i1K$~
上面的SQL代码只是一个时间段 G=LK
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Dateadd(wk,datediff(wk,0,getdate()),-1) lh6N3d
Dateadd(wk,datediff(wk,0,getdate()),6) |D_4 iFC
就是表示本周时间段. .#Z"Sj
下面的SQL的条件部分,就是查询时间段在本周范围内的: _T_} k:&X
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ght3#
而在存储过程中 h^,av^lg^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) SXC
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &Mz]y?k'