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。 @&Nvb.5nT
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一、基础 m|]^f;7z
1、说明:创建数据库 Z@[,"{Sn
CREATE DATABASE database-name :>X7(&j8
2、说明:删除数据库 I
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drop database dbname 'd t}i<
3、说明:备份sql server Y;Ur8q
--- 创建 备份数据的 device JA{YdB;il
USE master ^TEODKS
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]Qu12Wg}P
--- 开始 备份 tl)}Be+Dt;
BACKUP DATABASE pubs TO testBack /B!m|)h5~
4、说明:创建新表 } )e`0)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) fiZv+R<x1
根据已有的表创建新表: okcl-q
A:create table tab_new like tab_old (使用旧表创建新表) =wj~6:Bf
B:create table tab_new as select col1,col2... from tab_old definition only FvJSJ.;E,
5、说明:删除新表 GBphab|
drop table tabname c}QJ-I
6、说明:增加一个列 *n*y!z
Alter table tabname add column col type r\
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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。 vv0zUvmT
7、说明:添加主键: Alter table tabname add primary key(col) t3GK{X
说明:删除主键: Alter table tabname drop primary key(col) 1}BNG ,n
8、说明:创建索引:create [unique] index idxname on tabname(col....) 4jz]c"p-
删除索引:drop index idxname <dN=d3S
注:索引是不可更改的,想更改必须删除重新建。 iCK$ o_`?
9、说明:创建视图:create view viewname as select statement O5{XT]:
删除视图:drop view viewname x5|v#
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10、说明:几个简单的基本的sql语句 ;Bb5KD
选择:select * from table1 where 范围 vUK>4^{J5
插入:insert into table1(field1,field2) values(value1,value2) _#4,&bh8
删除:delete from table1 where 范围 ,\M_q">npc
更新:update table1 set field1=value1 where 范围 :7ngVc
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _B1uE2j9
排序:select * from table1 order by field1,field2 [desc] J:lwq@u
总数:select count as totalcount from table1 V[I<9xaE
求和:select sum(field1) as sumvalue from table1 -$)Et |
平均:select avg(field1) as avgvalue from table1 V`M,d~:Pr"
最大:select max(field1) as maxvalue from table1 ,xz^k/.
最小:select min(field1) as minvalue from table1 Q*C4
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11、说明:几个高级查询运算词 1hviT&
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A: UNION 运算符 4sj%:
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 nwo!A3w:
B: EXCEPT 运算符 IA^)`l 7H
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 7S2F^,w
C: INTERSECT 运算符 |+:ZO5FaO
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 z=p
注:使用运算词的几个查询结果行必须是一致的。 4LjSDgA
12、说明:使用外连接 >Y'yM4e*
A、left outer join: C%c `@="b
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 \Ep/'Tj&
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c J3x7i8
B:right outer join: na3kHx@
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 @L!#i*> 9
C:full outer join: W[>Tq T63
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 |I}+!DDuv
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二、提升 \r%Vgne-g
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) VQ?H:1R
法一:select * into b from a where 1<>1 9`v:$(I
法二:select top 0 * into b from a 9(F?|bfk
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) LQ@|M.$A
insert into b(a, b, c) select d,e,f from b; 02^(z6K'&?
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) qX'a&~s)n
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R$fIb}PDr
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. T+nC>}*jgJ
4、说明:子查询(表名1:a 表名2:b) (bt]GAxb1
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) ];d:z[\P
5、说明:显示文章、提交人和最后回复时间 $JB:rozE
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b gyQ9Z}
6、说明:外连接查询(表名1:a 表名2:b) =(X'c.%i
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7=.VqC^
7、说明:在线视图查询(表名1:a ) Z{
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select * from (SELECT a,b,c FROM a) T where t.a > 1; Au._n,<
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 +@uC:3jM
select * from table1 where time between time1 and time2 ^Ai_/! "
select a,b,c, from table1 where a not between 数值1 and 数值2 .r| vz6tU?
9、说明:in 的使用方法 p\_qHq\;j
select * from table1 where a [not] in ('值1','值2','值4','值6') GLQvAHC
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]GtR8w@w
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =Xjuz:9D~
11、说明:四表联查问题: r)5\3j[P
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... A] ?O&m|
12、说明:日程安排提前五分钟提醒 d+2O^of:T
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 J8v:a`bX&
13、说明:一条sql 语句搞定数据库分页 7oe@bS/Z
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 M y"!j,Up
14、说明:前10条记录 C9g~l}=$&
select top 10 * form table1 where 范围 0^&R7Rv c
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.) xnQGCw?S&}
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @
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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 e~s7ggg2k
(select a from tableA ) except (select a from tableB) except (select a from tableC) '+I
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17、说明:随机取出10条数据 [9U srpYi
select top 10 * from tablename order by newid() ;9 &1JX
18、说明:随机选择记录 .&Pe7`.BE
select newid() DYKV54\ue
19、说明:删除重复记录 eAYW%a
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) oZ>`Qu
20、说明:列出数据库里所有的表名 )4)iANH?
select name from sysobjects where type='U' 4`-?r%$,:
21、说明:列出表里的所有的 31sgf5 s
select name from syscolumns where id=object_id('TableName') V=4u7!ha
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。 lcT+$4zk.
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 TnBG MI,g'
显示结果: ]<;i}n|
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type vender pcs WUWb5xA
电脑 A 1 _{`'{u
电脑 A 1 ]AC!R{H
光盘 B 2 K# i*9sM
光盘 A 2 )~blx+ \y
手机 B 3
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手机 C 3 {.D2ON
23、说明:初始化表table1 0"<;You
TRUNCATE TABLE table1 %c&Ah
24、说明:选择从10到15的记录 )|h;J4V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc aH PSnB&
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三、技巧 FX|lhwmc(
1、1=1,1=2的使用,在SQL语句组合时用的较多 KpbZnW}g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, =7]Q6h@X
如: aBVEk2 p
if @strWhere !='' %QsSR'`
begin .xz,pn}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X\^& nLa
end svq9@!go
else t2-nCRXEP
begin k`7.p,;}U
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Nzi/3r7m
end R3{*v =ov
我们可以直接写成 [mB(GL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rxgVT4
2、收缩数据库 [rUh;_b\D
--重建索引 X|1_0
DBCC REINDEX }u3H4S<o
DBCC INDEXDEFRAG L >Ez-
--收缩数据和日志 spU!t-n67
DBCC SHRINKDB J'\eS./w|
DBCC SHRINKFILE %I|+_ z&x
3、压缩数据库 vBnKu
dbcc shrinkdatabase(dbname) $XQ;~i
4、转移数据库给新用户以已存在用户权限 d1uG[
exec sp_change_users_login 'update_one','newname','oldname' IGK_1@tq
go }Uwkef.Q
5、检查备份集 27*(oT
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' zA'gb'MmW
6、修复数据库 -0KbdHIKb'
ALTER DATABASE [dvbbs] SET SINGLE_USER L=$?q/=-
GO -M1~iOb
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Hc&uE3=%sL
GO S QM(8*:X
ALTER DATABASE [dvbbs] SET MULTI_USER <(bCz>o|
GO R%)2(\
7、日志清除 RlslF9f
SET NOCOUNT ON @!&Jgg53G
DECLARE @LogicalFileName sysname, Y( V3PnH
@MaxMinutes INT, K[#v(<)
@NewSize INT Qw6KX#n
USE tablename -- 要操作的数据库名 p-i.ITRS
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uzVG q!'H
@MaxMinutes = 10, -- Limit on time allowed to wrap log. I_zk'
@NewSize = 1 -- 你想设定的日志文件的大小(M) D*XZT{1g
-- Setup / initialize g]==!!^<D
DECLARE @OriginalSize int $||ns@F+
SELECT @OriginalSize = size RI5g+Du?
FROM sysfiles ){:q;E]^fB
WHERE name = @LogicalFileName 47C(\\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3I;xU(rv
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + a* W_fxb
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^z *):e
FROM sysfiles 5!SoN}$
WHERE name = @LogicalFileName 0279g
CREATE TABLE DummyTrans 2Z/][?Jj{
(DummyColumn char (8000) not null) ebO`A2V'(
DECLARE @Counter INT, rF8W(E_=
@StartTime DATETIME, xqQ~|
@TruncLog VARCHAR(255) %0+h
SELECT @StartTime = GETDATE(), cXOje"5i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -40'[a9E
DBCC SHRINKFILE (@LogicalFileName, @NewSize) }DDVGs[
EXEC (@TruncLog) r sX$fU8
-- Wrap the log if necessary. ?ae[dif
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 4]DAh
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) z\Pe{J
AND (@OriginalSize * 8 /1024) > @NewSize .# !'c
BEGIN -- Outer loop. {?@t/.4[W3
SELECT @Counter = 0 ;o-\. =l
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) TbKP8zw{
BEGIN -- update "}'8`k+d
INSERT DummyTrans VALUES ('Fill Log') g+ >=C
DELETE DummyTrans P0'e"\$
SELECT @Counter = @Counter + 1 H}) Dcg3
END nJtEUVMt
EXEC (@TruncLog) 7x[LF ^o
END v+!y;N;Q
SELECT 'Final Size of ' + db_name() + ' LOG is ' + fCt^FU
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /RJ6nmN@}
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' cX|[WT0[I
FROM sysfiles zz(!t eBC
WHERE name = @LogicalFileName ;NiArcAS!
DROP TABLE DummyTrans X
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SET NOCOUNT OFF $zk^yumdE
8、说明:更改某个表 d]O_E4X*
exec sp_changeobjectowner 'tablename','dbo' lgkl? 0!
9、存储更改全部表 #D|!
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch sorSyuGr
@OldOwner as NVARCHAR(128), h`
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@NewOwner as NVARCHAR(128) >\|kJ?h
AS Cec9#C
DECLARE @Name as NVARCHAR(128) la
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DECLARE @Owner as NVARCHAR(128) YBYB OH
DECLARE @OwnerName as NVARCHAR(128) *3A3>Rwu
DECLARE curObject CURSOR FOR M>*0r<qn
select 'Name' = name, E;6Y? vJ
'Owner' = user_name(uid) ~-XOvKJb
from sysobjects G$?|S@I,
where user_name(uid)=@OldOwner 4zo4H~@gk
order by name !Y ;H(.A/
OPEN curObject N5pinR5 H
FETCH NEXT FROM curObject INTO @Name, @Owner Xt</ -`
WHILE(@@FETCH_STATUS=0) Od0S2hHO
BEGIN y-w2O]
if @Owner=@OldOwner Ujce |>Wn
begin G0_&gx`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,{.zh&=4
exec sp_changeobjectowner @OwnerName, @NewOwner g".d"d{
end :V&N\>Wo
-- select @name,@NewOwner,@OldOwner [D*J[?yt
FETCH NEXT FROM curObject INTO @Name, @Owner uL2"StW
END 1*C:hg@
close curObject Zu\p;!e
deallocate curObject ksB
GO w{k1Y+1
10、SQL SERVER中直接循环写入数据 u~$WH, P3
declare @i int qSFc=Wwc
set @i=1 1 L+=|*:
while @i<30 $7Jfb<y
begin O0@w(L-
insert into test (userid) values(@i) %xf)m[JU=
set @i=@i+1 cU7rq j_
end 8|1`Tn}o
小记存储过程中经常用到的本周,本月,本年函数 5;X {.2
Dateadd(wk,datediff(wk,0,getdate()),-1) c u\ls^
Dateadd(wk,datediff(wk,0,getdate()),6) 2{Wo-B,wt~
Dateadd(mm,datediff(mm,0,getdate()),0) ~R :<Bw
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7IA3q{P
Dateadd(yy,datediff(yy,0,getdate()),0) kP)YgkE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) FhWmO
上面的SQL代码只是一个时间段 @@'nit
Dateadd(wk,datediff(wk,0,getdate()),-1) 54<6Dy f
Dateadd(wk,datediff(wk,0,getdate()),6) Dc5bkm
就是表示本周时间段. M,crz
下面的SQL的条件部分,就是查询时间段在本周范围内的: Up<~0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) HH"$#T^-
而在存储过程中 , p_G/OU
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /nc~T3j
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {*N^C@