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。 gS!zaD7Nr
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一、基础 we33GMxHl`
1、说明:创建数据库 u"U7aYGkY
CREATE DATABASE database-name cE*d(g
2、说明:删除数据库 'Z6x\p
drop database dbname gAK"ShOhG=
3、说明:备份sql server ]&"01M~+K
--- 创建 备份数据的 device fy>~GFk(
USE master Yo}QW;,g
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' N}'2GBqfU4
--- 开始 备份 I$ ?.9&.&
BACKUP DATABASE pubs TO testBack =<r1sqf
4、说明:创建新表 XJA];9^
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) tf>"fU\P
根据已有的表创建新表: 55zy]|F"
A:create table tab_new like tab_old (使用旧表创建新表) ? RID4xu!
B:create table tab_new as select col1,col2... from tab_old definition only Ime"}*9
5、说明:删除新表 PebyH"M(
drop table tabname ~Vf
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6、说明:增加一个列 wu0q.]
Alter table tabname add column col type rouaT
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。 $nNCBC=
7、说明:添加主键: Alter table tabname add primary key(col) T:*l+<?
说明:删除主键: Alter table tabname drop primary key(col) j;EH[3
8、说明:创建索引:create [unique] index idxname on tabname(col....) }(9ZME<(
删除索引:drop index idxname ` c"
注:索引是不可更改的,想更改必须删除重新建。 ^(Wu$\SA
9、说明:创建视图:create view viewname as select statement Upz?x{>x
删除视图:drop view viewname CTQJ=R"
10、说明:几个简单的基本的sql语句 ~L"?C
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) )<
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删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 R|]n;*y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {vp*m:K
排序:select * from table1 order by field1,field2 [desc] [G"Va_A8
总数:select count as totalcount from table1 5Rae?*XH
求和:select sum(field1) as sumvalue from table1 yVyh\u\
平均:select avg(field1) as avgvalue from table1 pL,l
最大:select max(field1) as maxvalue from table1 yKC1h`2
最小:select min(field1) as minvalue from table1 G|z%T`!U1;
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11、说明:几个高级查询运算词 f%rZ2h)
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A: UNION 运算符 BCh|^Pk
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。 6K^O.VoV^J
B: EXCEPT 运算符 wQ81wfr1:
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。 No*[@D]g
C: INTERSECT 运算符 H`rd bE
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。 (btmg<WT"
注:使用运算词的几个查询结果行必须是一致的。 H4<Q}([w
12、说明:使用外连接 V+t's*9o3
A、left outer join: l\ VrD2j8
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。 $t0JfDd6Ky
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _7'5I A
B:right outer join: upGLZ#
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 _IWLC{%V
C:full outer join: xcH&B%;f
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 #tA/)Jvi
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二、提升 x
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) d-TpY*v
法一:select * into b from a where 1<>1 iWIq~t*,H]
法二:select top 0 * into b from a }lGui>/D
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7 4]qz,
insert into b(a, b, c) select d,e,f from b; s%1ZraMvJ
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) *NC@o*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #@F.wV0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &_74h);2I:
4、说明:子查询(表名1:a 表名2:b) y2=yh30L0E
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ~7m+N)5
5、说明:显示文章、提交人和最后回复时间 "Cs36k
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -,2CMS#N
6、说明:外连接查询(表名1:a 表名2:b) -_XTy!I
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /y(0GP4A
7、说明:在线视图查询(表名1:a ) q}W})
select * from (SELECT a,b,c FROM a) T where t.a > 1; )W&{OMr
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 W:K '2j
select * from table1 where time between time1 and time2 PlCj<b1D:
select a,b,c, from table1 where a not between 数值1 and 数值2 gyuBmY
9、说明:in 的使用方法 K|I<kA~!H
select * from table1 where a [not] in ('值1','值2','值4','值6') |qBcE
10、说明:两张关联表,删除主表中已经在副表中没有的信息 JX{_,2*$
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) b7B|$T,
11、说明:四表联查问题: ',/2J0_
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 ..... bAwKmk9C
12、说明:日程安排提前五分钟提醒 mv^X{T
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !;0K=~(Y^
13、说明:一条sql 语句搞定数据库分页 "F[7b!>R
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 hw(\3h()
14、说明:前10条记录 B<0Kl.V
select top 10 * form table1 where 范围 Sb(OG 6
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.) h}kJ,n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -gUp/#l1
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 %Aqf=R_^
(select a from tableA ) except (select a from tableB) except (select a from tableC) $lq.*UQ;0
17、说明:随机取出10条数据 SmIcqM
select top 10 * from tablename order by newid() 4]6-)RHFB
18、说明:随机选择记录 +}PN+:yV
select newid() Je}0KW3G9L
19、说明:删除重复记录 +wxsAGy_j
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) c94=>p6
20、说明:列出数据库里所有的表名 Sa
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select name from sysobjects where type='U' J_?v=dW`
21、说明:列出表里的所有的 :Qhrh(i
select name from syscolumns where id=object_id('TableName') b'Km-'MtH
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 "p7nngn~
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type U_l9CZ
显示结果: YoBe!-E
type vender pcs v*%52_
电脑 A 1 ESYF4-d+
电脑 A 1 V@[C=K
光盘 B 2 {Wu[e,p
光盘 A 2 2_y]MXG+%
手机 B 3 `.J17mQe"
手机 C 3 5~j#Z (}u
23、说明:初始化表table1 A\#z<h[>
TRUNCATE TABLE table1 D:/q<<|
24、说明:选择从10到15的记录 "%\hDL;
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 57-Hx;
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三、技巧 O1bW, n(
1、1=1,1=2的使用,在SQL语句组合时用的较多 ;lvcg)}l
"where 1=1" 是表示选择全部 "where 1=2"全部不选, T6QRr}8`/J
如: uxB`
if @strWhere !='' M X8|;t
begin @`dlhz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *@H\J e`
end gKQV99
else K/K-u
begin I]E 3&gnC
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Qd{8.lB~LQ
end _TGs .t
我们可以直接写成 *3rs+0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ft$RF
2、收缩数据库 |`t 6lVO,Z
--重建索引 X%3?sH
DBCC REINDEX H!&_Tv[
DBCC INDEXDEFRAG Tjhy@3
--收缩数据和日志 Fx|`0LI+C
DBCC SHRINKDB ][
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DBCC SHRINKFILE 9@yF7
3、压缩数据库 sRA2O/yKCE
dbcc shrinkdatabase(dbname) U3Z=X TB
4、转移数据库给新用户以已存在用户权限 N9-7YQ`D
exec sp_change_users_login 'update_one','newname','oldname' DA.k8M
go ^6 z"@+;*
5、检查备份集 N2"B\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' KmTFJ,iM
6、修复数据库 w"wW0uE^
ALTER DATABASE [dvbbs] SET SINGLE_USER b^Re947{g
GO gXJBb+P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK QA*<$v
GO e6Y>Bk
ALTER DATABASE [dvbbs] SET MULTI_USER t>/x-{bH\
GO )*>wa%[-q
7、日志清除 cw{TS
SET NOCOUNT ON y<E];ub
DECLARE @LogicalFileName sysname, sQac%.H;`U
@MaxMinutes INT, dC{dw^
@NewSize INT _io'8X2K%
USE tablename -- 要操作的数据库名 Uq$/Q7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 .<F46?HS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `SsoRPW&$
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7XK0vKmW3
-- Setup / initialize 8hD[z}
DECLARE @OriginalSize int e-`.Ht
SELECT @OriginalSize = size #$x,PeG
FROM sysfiles S`U8\KTi
WHERE name = @LogicalFileName o3/o2[s
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #-<Go'yF
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4&sf{tI
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?'z/S5&j
FROM sysfiles CV.|~K0O
WHERE name = @LogicalFileName &h5Y_no GX
CREATE TABLE DummyTrans fy4zBI@
(DummyColumn char (8000) not null) Q_|}~4_+
DECLARE @Counter INT, 8c+V$rH_
@StartTime DATETIME, C| ~A]wc=
@TruncLog VARCHAR(255) 2cH RiRT
SELECT @StartTime = GETDATE(), gTXpaB<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' A5TSbW']+5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) abQ.N
EXEC (@TruncLog) {tUe(
-- Wrap the log if necessary. TZ5TkE;1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired $R/@8qnP
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _&BK4?H@b
AND (@OriginalSize * 8 /1024) > @NewSize =g9n =spAn
BEGIN -- Outer loop. WSu6chz)
SELECT @Counter = 0 kpIn_Ea
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Z%]K,9K
BEGIN -- update G?'^"ae"Z
INSERT DummyTrans VALUES ('Fill Log') gVfFEF.
DELETE DummyTrans z R?R,k)m
SELECT @Counter = @Counter + 1 w;`Jj-
END $|- Lw!)D
EXEC (@TruncLog) m0TV i] v
END JM,%|
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + _d5:Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Y
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' rs{)4.I
FROM sysfiles Sk cK>i.[
WHERE name = @LogicalFileName ;v@ G
DROP TABLE DummyTrans OW4j!W
SET NOCOUNT OFF qqf`z,u
8、说明:更改某个表 Zek@xr;]
exec sp_changeobjectowner 'tablename','dbo' U
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9、存储更改全部表 LJ/He[r|[
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch S3ooG1 4Ls
@OldOwner as NVARCHAR(128), eV|N@
@NewOwner as NVARCHAR(128) ]EX6Y
AS ;rT'~?q
DECLARE @Name as NVARCHAR(128) 0N$7(.
DECLARE @Owner as NVARCHAR(128) UpG DLb f^
DECLARE @OwnerName as NVARCHAR(128) $lJcC |*
DECLARE curObject CURSOR FOR /=m AVA
select 'Name' = name, (yqe4
'Owner' = user_name(uid) DJ, LQj
from sysobjects i *.Y
where user_name(uid)=@OldOwner >,{sFc
order by name Q^Cm3|ZO
OPEN curObject BqNeY<zB*
FETCH NEXT FROM curObject INTO @Name, @Owner f47]gtB-
WHILE(@@FETCH_STATUS=0) EVX3uC}{
BEGIN ju{Y6XJ)
if @Owner=@OldOwner B-rE8\
begin b?i+nhqI
set @OwnerName = @OldOwner + '.' + rtrim(@Name) CvY+b^ ;
exec sp_changeobjectowner @OwnerName, @NewOwner g%f5hy
end *#XZ*Ga
-- select @name,@NewOwner,@OldOwner '6dVe2V
FETCH NEXT FROM curObject INTO @Name, @Owner Snf_{A<
END gM3:J:N
close curObject pX SShU#
deallocate curObject 4=([v;fc
GO Q%JI-&K
10、SQL SERVER中直接循环写入数据 ~Kw#^.$3T
declare @i int ~V8z%s@
set @i=1 aZ4EcQ@-$]
while @i<30 +)sX8zb*gY
begin lA5Dag'
insert into test (userid) values(@i) n^4R]9U
set @i=@i+1 2Cz haO
end ;|5-{+2 U%
小记存储过程中经常用到的本周,本月,本年函数 $9,&BW_*
Dateadd(wk,datediff(wk,0,getdate()),-1) LgNIb
Dateadd(wk,datediff(wk,0,getdate()),6) &W@2n&U.q
Dateadd(mm,datediff(mm,0,getdate()),0) ^z{szy?Fg
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) z$%twBg}#
Dateadd(yy,datediff(yy,0,getdate()),0) :25LQf^nz
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 'ZuS
上面的SQL代码只是一个时间段 y!#-[K:
Dateadd(wk,datediff(wk,0,getdate()),-1) rL{R=0
Dateadd(wk,datediff(wk,0,getdate()),6) N y'\Q"Y]
就是表示本周时间段. .T'@P7Hdx
下面的SQL的条件部分,就是查询时间段在本周范围内的: CQ!pt@|d
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 3PNdc}h
而在存储过程中 YZg#H)w%
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) t WI-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =8\.fp