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。 b=QO ^
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一、基础 ;X\>oV3#
1、说明:创建数据库 5RTAM
CREATE DATABASE database-name ''wWw(2O
2、说明:删除数据库 lE[LdmwDrb
drop database dbname 6[c
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3、说明:备份sql server 7BF't!-2F
--- 创建 备份数据的 device )j@k[}R#g
USE master FQ?H%UcW
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d <qbUk3;
--- 开始 备份 ag?@5q3J}
BACKUP DATABASE pubs TO testBack {:Z# 8dGe
4、说明:创建新表 N:clwmo
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) \GbT^!dj
根据已有的表创建新表: C|W_j&S65
A:create table tab_new like tab_old (使用旧表创建新表) mb?DnP,z
B:create table tab_new as select col1,col2... from tab_old definition only '8k\a{t_z
5、说明:删除新表 r,MgIv(L
drop table tabname bK("8T\?
6、说明:增加一个列 *`);_EVc
Alter table tabname add column col type tZU"Ud
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。 *s?&)][
7、说明:添加主键: Alter table tabname add primary key(col) 4^alAq^
说明:删除主键: Alter table tabname drop primary key(col) t22BO@gt74
8、说明:创建索引:create [unique] index idxname on tabname(col....) =YZp,{T
删除索引:drop index idxname eJ%~6c`@!
注:索引是不可更改的,想更改必须删除重新建。 QKZm<lUL
9、说明:创建视图:create view viewname as select statement p0$K.f|
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删除视图:drop view viewname Gr?"okaA
10、说明:几个简单的基本的sql语句 klUxt?-
选择:select * from table1 where 范围 5HL JkOV5
插入:insert into table1(field1,field2) values(value1,value2) n4k.tq
删除:delete from table1 where 范围 ERGDo=j
更新:update table1 set field1=value1 where 范围 g=b[V
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! **-%5~
排序:select * from table1 order by field1,field2 [desc] ))G%C6-
总数:select count as totalcount from table1 \fU{$
求和:select sum(field1) as sumvalue from table1 tmK@Veb*a'
平均:select avg(field1) as avgvalue from table1 XOgX0cRC4
最大:select max(field1) as maxvalue from table1 N iNZh;
最小:select min(field1) as minvalue from table1 G5=(3 V%
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11、说明:几个高级查询运算词 (rZq0*
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A: UNION 运算符 )@1_Dm@0b
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。 IOTHk+w
B: EXCEPT 运算符 mkj`z
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。 S][:b
C: INTERSECT 运算符 ]ueq&|
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 ;y22
注:使用运算词的几个查询结果行必须是一致的。 '$1-A%e$1
12、说明:使用外连接 (sJ{27b_
A、left outer join: 6$)Yqg`X
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。 qdZn9i
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 c4L5"_#`x-
B:right outer join: faD(,H
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。 9N=Dls
C:full outer join: :7:Nx`D8
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。 a_QO)
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二、提升 aKH\8O4L5
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o~<fw]y
法一:select * into b from a where 1<>1 ,a^_
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法二:select top 0 * into b from a i7e{REBXb
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) zMtK_ccQ
insert into b(a, b, c) select d,e,f from b; rS(693kb
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) E# e=<R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ",&}vfD4M
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,W{Qv<oo
4、说明:子查询(表名1:a 表名2:b) y<)Lr}gP
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) tEiN(KA!5
5、说明:显示文章、提交人和最后回复时间
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b quGb;)3
6、说明:外连接查询(表名1:a 表名2:b) ]#S1AvT
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c cQ3Dk<GZ
7、说明:在线视图查询(表名1:a ) rU.ew~
select * from (SELECT a,b,c FROM a) T where t.a > 1; 0lmoI4bW}s
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 Uy_`=JZ
select * from table1 where time between time1 and time2 js8uvZ i
select a,b,c, from table1 where a not between 数值1 and 数值2 q G=`'%,m
9、说明:in 的使用方法 :l3Tt<
select * from table1 where a [not] in ('值1','值2','值4','值6') ih ,8'D4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 P>4(+s
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0qJ(3N
11、说明:四表联查问题: Sw'DS
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 ..... 2!]':(8mR
12、说明:日程安排提前五分钟提醒 wQM(Lm#Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 VEb}KFyP
13、说明:一条sql 语句搞定数据库分页 AU-/-h=Mr
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 &)xoR4!2
14、说明:前10条记录 !i)?j@D
select top 10 * form table1 where 范围 jew?cnRmd
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.) N<N!it
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) g%4|vA8
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 S'6(&"XCH
(select a from tableA ) except (select a from tableB) except (select a from tableC) O;qS3
17、说明:随机取出10条数据 )2bPu[U
select top 10 * from tablename order by newid() R['qBHQ?
18、说明:随机选择记录 l6l)M
select newid() h"wXmAf4%
19、说明:删除重复记录 zpg*hlv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) }p8a'3@Z
20、说明:列出数据库里所有的表名 KS(s<ip|
select name from sysobjects where type='U' DJrA@hm/Y
21、说明:列出表里的所有的 m:p1O3[R
select name from syscolumns where id=object_id('TableName') n~K_|
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。 !n)2HDYhx,
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 (q:L_zFj>"
显示结果: l)XzU&Sc~
type vender pcs ~5cLI;4h
电脑 A 1 @xO<~
电脑 A 1 HK:?Y[ebs
光盘 B 2 AO8`ItNZdT
光盘 A 2 D}\%
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手机 B 3 s)ZL`S?</
手机 C 3 7U?x8%H*
23、说明:初始化表table1 #G9S[J=xe
TRUNCATE TABLE table1 ]'T-6
24、说明:选择从10到15的记录 1[X+6viE
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6\b B#a
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--
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三、技巧 AX]lMe
1、1=1,1=2的使用,在SQL语句组合时用的较多 oqUtW3y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, u4#BD!W
如: nJ'O(Wh,)
if @strWhere !='' /Pi{Mv eZM
begin MlS<txFPS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere XY0Gjo0
end Wl::tgU
else PN0:,.4
begin _j<46^
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' kQ{pFFO
end Os?~U/
我们可以直接写成 ho fZpM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere I&R4.;LW
2、收缩数据库 yy/wSk
--重建索引 p0'A\@|
DBCC REINDEX HPr5mWs:
DBCC INDEXDEFRAG ,$W7Q
--收缩数据和日志 [^~Fu9+"
DBCC SHRINKDB Wx;9N
DBCC SHRINKFILE 9s5CqB
3、压缩数据库 ~~:i+-[
dbcc shrinkdatabase(dbname) jIAl7aoY
4、转移数据库给新用户以已存在用户权限 N7}.9%EV
exec sp_change_users_login 'update_one','newname','oldname' h_x"/z&
go 3D;\V&([
5、检查备份集 }UQBaqDH
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' m3P%E8<Q#
6、修复数据库 T4o}5sq}S
ALTER DATABASE [dvbbs] SET SINGLE_USER 'UW7zL5
GO ##1[/D(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _@jl9<t=_
GO 8$xg\l0?KK
ALTER DATABASE [dvbbs] SET MULTI_USER (lS&P"Xi
GO J3y5R1?EP
7、日志清除 0@^YxU[YN
SET NOCOUNT ON MDl
DECLARE @LogicalFileName sysname, V:F)m!
@MaxMinutes INT, {u3^#kF
@NewSize INT hY/SR'8
USE tablename -- 要操作的数据库名 D3(|bSca
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 H@,jNIh~h
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >L?/Ph %d
@NewSize = 1 -- 你想设定的日志文件的大小(M) ^e<0-uM"s
-- Setup / initialize (9fq UbG
DECLARE @OriginalSize int BLuILE:$
SELECT @OriginalSize = size mNWmp_c,1
FROM sysfiles "xdXHuX
WHERE name = @LogicalFileName [[oX$0Fp\!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + s)]i0+!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + FzA_-d/_dg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' R%8nR6iG"
FROM sysfiles hTf]t
WHERE name = @LogicalFileName T_y 'cvh
CREATE TABLE DummyTrans Yf7n0Etd,
(DummyColumn char (8000) not null) W^60BZ
DECLARE @Counter INT, o/2\8
@StartTime DATETIME, eIg '
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@TruncLog VARCHAR(255) r-H~MisL
SELECT @StartTime = GETDATE(), -`&4>\o2Lx
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $9M>B<]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;BejFcb
EXEC (@TruncLog) z,I7 PY& G
-- Wrap the log if necessary. k2,n:7
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #Z98D9Pv`o
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) J0C<Qb[
AND (@OriginalSize * 8 /1024) > @NewSize it D%sKo
BEGIN -- Outer loop. 'nBJ[$2^
SELECT @Counter = 0 :hjeltt
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #:DDx5%x<b
BEGIN -- update ?b^VEp.;}
INSERT DummyTrans VALUES ('Fill Log') y%v<Cp@R
DELETE DummyTrans xXp\U'Ad~~
SELECT @Counter = @Counter + 1 toX4kmC
END Bl3G_Ep
EXEC (@TruncLog) T5Sa9\`>
END B`T|M$Ug
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &gIu<*u<
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + gE`G3kgn{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' D2[uex
FROM sysfiles #HJ F==
WHERE name = @LogicalFileName tA3]6SIK@
DROP TABLE DummyTrans :_p3nb[r
SET NOCOUNT OFF s~IOc%3
8、说明:更改某个表 QKE$>G
exec sp_changeobjectowner 'tablename','dbo' ^qIp+[/'
9、存储更改全部表 [o*u!2 r
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Yw\}'7
@OldOwner as NVARCHAR(128), gmj
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@NewOwner as NVARCHAR(128) /-8v]nRB
AS ;]i&AAbj
DECLARE @Name as NVARCHAR(128) slDxsb
DECLARE @Owner as NVARCHAR(128) gt';_
DECLARE @OwnerName as NVARCHAR(128) V%<<Udu<
DECLARE curObject CURSOR FOR `(_cR@\
select 'Name' = name, slOki|p;
'Owner' = user_name(uid) i"F'n0*L
from sysobjects |pqLwnOu
where user_name(uid)=@OldOwner e ! 6SJ7xC
order by name B5 C]4
OPEN curObject 0u'4kF!P!
FETCH NEXT FROM curObject INTO @Name, @Owner mE}``
WHILE(@@FETCH_STATUS=0) 0{BPT>'
BEGIN {YcVeCq+N
if @Owner=@OldOwner U#Wc!QN-t
begin one^XYy1%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) w>IkC+.?
exec sp_changeobjectowner @OwnerName, @NewOwner 9RE{,mos2v
end --Dw
-- select @name,@NewOwner,@OldOwner K.*?\)&
FETCH NEXT FROM curObject INTO @Name, @Owner ?\<2*sW [k
END KQJn\#>
close curObject 83412@&
deallocate curObject e%R+IH5i
GO +&4PGv53J
10、SQL SERVER中直接循环写入数据 ,b-wo
declare @i int U4 m[@wF
set @i=1 SR*%-JbA
while @i<30 N>/*)Frt
begin PUltn}M
insert into test (userid) values(@i) 95T%n{rz
set @i=@i+1 79s6U^vv"
end lE?e1mz{
小记存储过程中经常用到的本周,本月,本年函数 dsR{
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Dateadd(wk,datediff(wk,0,getdate()),-1) G qk"%irZ
Dateadd(wk,datediff(wk,0,getdate()),6) `RthX\Tof
Dateadd(mm,datediff(mm,0,getdate()),0) F}H!vh[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 9(ZzwkD'>
Dateadd(yy,datediff(yy,0,getdate()),0) ?OZbns~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) yx{Ac|<mR
上面的SQL代码只是一个时间段 9`4h"9dO
Dateadd(wk,datediff(wk,0,getdate()),-1) ~_8Ve\Y^ /
Dateadd(wk,datediff(wk,0,getdate()),6) )N)ziAy}
就是表示本周时间段. :54|Z5h|
下面的SQL的条件部分,就是查询时间段在本周范围内的: ?9H7Twi+T
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7/PHg)&
而在存储过程中 t<ftEJU"'w
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) R:E6E@T
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Qc[[@=S%