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。 ;I>`!|mT
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一、基础 Ap/WgVw;
1、说明:创建数据库 D+OkD-8q
CREATE DATABASE database-name FwyPmtBj
2、说明:删除数据库 ]l`DR4
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drop database dbname 2bqwnRT}
3、说明:备份sql server VrpYBU
--- 创建 备份数据的 device {PZe!EQ
USE master 3iB8QO;pp
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Nbr{)h
--- 开始 备份 <T['J]k%
BACKUP DATABASE pubs TO testBack Ks4TBi&J
4、说明:创建新表 nN[,$`JD,
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [yz;OoA:;
根据已有的表创建新表: m9/a!|fBE
A:create table tab_new like tab_old (使用旧表创建新表) Mvux=Ws
B:create table tab_new as select col1,col2... from tab_old definition only H_9~gi
5、说明:删除新表 tZJKB1#WbP
drop table tabname sB $!X@
6、说明:增加一个列 .$Y[>9
Alter table tabname add column col type ^-DK<jZ^
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。 46b.= }
7、说明:添加主键: Alter table tabname add primary key(col) \>+gZc]an
说明:删除主键: Alter table tabname drop primary key(col) K|iNEhuc
8、说明:创建索引:create [unique] index idxname on tabname(col....) rS=6d6@
删除索引:drop index idxname B$)KZR(u
注:索引是不可更改的,想更改必须删除重新建。 Epx.0TA= t
9、说明:创建视图:create view viewname as select statement t;'__">:q
删除视图:drop view viewname _ v-sb(*
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10、说明:几个简单的基本的sql语句 YPN|qn(
选择:select * from table1 where 范围 `|gCbs95
插入:insert into table1(field1,field2) values(value1,value2) GFvOrRlP\
删除:delete from table1 where 范围 s;bqUY?LD
更新:update table1 set field1=value1 where 范围 BzDS
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _b+3;Dy
排序:select * from table1 order by field1,field2 [desc] t<4+CC2H
总数:select count as totalcount from table1 K~uoZ~_gA
求和:select sum(field1) as sumvalue from table1 *Nv<,Br,F
平均:select avg(field1) as avgvalue from table1 1Z`zdZs
最大:select max(field1) as maxvalue from table1 !$j'F? 2>
最小:select min(field1) as minvalue from table1 \!_ >ul
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11、说明:几个高级查询运算词 nF=h|rN
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A: UNION 运算符 Q.x3_+CX
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。 x,n;GR
B: EXCEPT 运算符 8ED6C"6
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。 wuPx6hCl
C: INTERSECT 运算符 \5Hfe;ny-~
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。 'Ic$p>
注:使用运算词的几个查询结果行必须是一致的。 'C(YUlT2?P
12、说明:使用外连接 X4jtti
A、left outer join: #U^@)g6
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 X"yLo8y8$
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 dD=dPi#
B:right outer join: q?`bu:yS
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。 0 ~VniF^
C:full outer join: ^*Sb)tu\ W
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。 j#29L"
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二、提升 w9vqFtj
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [-Dx)N
法一:select * into b from a where 1<>1 $cc]pJy"}
法二:select top 0 * into b from a Q~nc:eWD
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) NI3_wV
insert into b(a, b, c) select d,e,f from b; `U)~fu/\2M
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) }yUZ(k#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 XJ.vj+XXb
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. %{axoGd
4、说明:子查询(表名1:a 表名2:b) W@#Y/L:${
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) %;GDg3L[p
5、说明:显示文章、提交人和最后回复时间 _Y=>^K]9K
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?,]25q
6、说明:外连接查询(表名1:a 表名2:b) m+zzhv1
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c EiSS_Lc
7、说明:在线视图查询(表名1:a ) G> "w$Us
select * from (SELECT a,b,c FROM a) T where t.a > 1; 4\>Cnc{
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 O",:0<
select * from table1 where time between time1 and time2 3#W>
select a,b,c, from table1 where a not between 数值1 and 数值2 2-FL&DE
9、说明:in 的使用方法 VGkwrS;+I
select * from table1 where a [not] in ('值1','值2','值4','值6') t=5K#SX}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7&E3d P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) sT| 8a
11、说明:四表联查问题: IF<pT)
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... awGI|d
12、说明:日程安排提前五分钟提醒 (z\@T`6`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 tQF,E&Jo8
13、说明:一条sql 语句搞定数据库分页 }PD?x4
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 h>9GfF3
14、说明:前10条记录 Hr:WE+'
select top 10 * form table1 where 范围 LNtBYdB`pK
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) iCnKQG
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Ng2qu!F7
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 kU0e;r1 N
(select a from tableA ) except (select a from tableB) except (select a from tableC) .hXxh)F
17、说明:随机取出10条数据 QYPsqkF*
select top 10 * from tablename order by newid() Ap=LlZ
18、说明:随机选择记录 |X0h-kX4
select newid() UO>ADRs}
19、说明:删除重复记录 h,45-#+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) rUR{MF&]D
20、说明:列出数据库里所有的表名 O$+0 .
select name from sysobjects where type='U' O)n"a\LD
21、说明:列出表里的所有的 vdV@G`)HPr
select name from syscolumns where id=object_id('TableName') ZG3u
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。 ihdN{Mx<2
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 Y:XE4v/)@L
显示结果: 1ve
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type vender pcs HTAJn_
电脑 A 1 D:4Iex9$F"
电脑 A 1 (w}iEm\b
光盘 B 2 )[i0~o[
光盘 A 2 LY(YgqL
手机 B 3 W{<_gD9
手机 C 3 r>+\9q1
23、说明:初始化表table1 r3*0`Rup
TRUNCATE TABLE table1 -A^18r
24、说明:选择从10到15的记录 yHsmX2s
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,3 =|a|p
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三、技巧 W1fEUVj
1、1=1,1=2的使用,在SQL语句组合时用的较多 >{C=\F#*L
"where 1=1" 是表示选择全部 "where 1=2"全部不选, JHC 6l
如: Yi1lvB?m
if @strWhere !='' ]3nka$wA*
begin .5Sw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `7[z%cuK
end yY+)IU.
else `83s97Sa
begin xM"k qRZ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' pUi|&F K">
end $dIu${lu
我们可以直接写成 >MwjUq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 78T9"CS
2、收缩数据库 lV<2+Is
--重建索引 VC$,Y
DBCC REINDEX ~gg(i"V
DBCC INDEXDEFRAG {}RE;5n\['
--收缩数据和日志 PT4Wox9U
DBCC SHRINKDB 6aRPm%
DBCC SHRINKFILE <pyLWmO
3、压缩数据库
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dbcc shrinkdatabase(dbname) B >2" O
4、转移数据库给新用户以已存在用户权限 ]zK'aod
exec sp_change_users_login 'update_one','newname','oldname' 2[-@
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go : .Y
5、检查备份集 [;~:',vHQf
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 4LO4SYW7
6、修复数据库 YW9r'{(D(I
ALTER DATABASE [dvbbs] SET SINGLE_USER )lh48Ag0t;
GO iYJ: P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 5G
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GO s F-{(
ALTER DATABASE [dvbbs] SET MULTI_USER F<H[-k*t/
GO wiHGTaR
7、日志清除 >v--R8I *
SET NOCOUNT ON $v5)d J
DECLARE @LogicalFileName sysname, #y;TSHx/
@MaxMinutes INT, nIc:<w]
@NewSize INT X)6}<A
USE tablename -- 要操作的数据库名 NX.%Rj*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 D_kz'0^|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ML eo3
@NewSize = 1 -- 你想设定的日志文件的大小(M) mXAGa8##j
-- Setup / initialize 2w"Xv,*.'i
DECLARE @OriginalSize int i;Y3pF0%P
SELECT @OriginalSize = size tf<}%4G
FROM sysfiles #x|xL7
WHERE name = @LogicalFileName yR}PC/>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Y%$@ZYW
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + GY% ^!r
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
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FROM sysfiles ygI81\D
WHERE name = @LogicalFileName t3LRmjL
CREATE TABLE DummyTrans H[oCI|k
(DummyColumn char (8000) not null) $FR1^|P/G
DECLARE @Counter INT, Jzu U
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@StartTime DATETIME, n@1;5)&k~
@TruncLog VARCHAR(255) q-?
k=RX`
SELECT @StartTime = GETDATE(), PH!^ww6
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4sJM!9eb[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) -o:
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EXEC (@TruncLog) ;zq3>A
-- Wrap the log if necessary. itotn!Wb`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }enS'Fpf`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) R;yi58Be
AND (@OriginalSize * 8 /1024) > @NewSize B8=r^!jEL
BEGIN -- Outer loop. xbUL./uj
SELECT @Counter = 0 5l_ >QB
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (_2Iu%F
BEGIN -- update +`jI z'+
INSERT DummyTrans VALUES ('Fill Log') _T\/kJ)Q\
DELETE DummyTrans ^v2-"mX<
SELECT @Counter = @Counter + 1 AlPk o($E*
END MZPXI{G
EXEC (@TruncLog) ?so=k&I-M
END sWtT"7>x
SELECT 'Final Size of ' + db_name() + ' LOG is ' + q!fdiv`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /i!3Fr"
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' +,8j]<wpo
FROM sysfiles b\
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WHERE name = @LogicalFileName FR57F(31
DROP TABLE DummyTrans NCu:E{([
SET NOCOUNT OFF cpY'::5.%
8、说明:更改某个表 %KjvV<f-a
exec sp_changeobjectowner 'tablename','dbo' :6h$1
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9、存储更改全部表 J~jxmh
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch O8\> ?4)
@OldOwner as NVARCHAR(128), }8lvi
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@NewOwner as NVARCHAR(128) 1&7~.S;km
AS E8gbm&x*
DECLARE @Name as NVARCHAR(128) uDe%M
DECLARE @Owner as NVARCHAR(128) 0oC5W?>8s
DECLARE @OwnerName as NVARCHAR(128) H0dHW;U<1
DECLARE curObject CURSOR FOR U<|hIv-&
select 'Name' = name, KzgW+6*G
'Owner' = user_name(uid) bh
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from sysobjects f52*s#4}
where user_name(uid)=@OldOwner h=a-~= 8
order by name 9>QGsf.3
OPEN curObject mQ$a^28=qR
FETCH NEXT FROM curObject INTO @Name, @Owner l^~E+F~
WHILE(@@FETCH_STATUS=0) \jR('5DcB
BEGIN }Cs.Hm0P
if @Owner=@OldOwner #.j[iN
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begin JXhHitUD
set @OwnerName = @OldOwner + '.' + rtrim(@Name) jWUpzf)q=T
exec sp_changeobjectowner @OwnerName, @NewOwner K-<kp!v
end ^Fop/\E
-- select @name,@NewOwner,@OldOwner ?^X
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FETCH NEXT FROM curObject INTO @Name, @Owner ^i;y2c
END ezz;NH
close curObject jIvSjlm I
deallocate curObject O,D/&0
GO M"W~%
10、SQL SERVER中直接循环写入数据 $E >)
declare @i int Uo<iZ3J
set @i=1 {e/6iSpT
while @i<30 U=Hx&g
begin Hyn* O)q!
insert into test (userid) values(@i) Y-ZTv(<
set @i=@i+1 Bu{1^g:
end X:/Y^Xu
小记存储过程中经常用到的本周,本月,本年函数 7^hwRZJ{
Dateadd(wk,datediff(wk,0,getdate()),-1) Y%GIKtP
Dateadd(wk,datediff(wk,0,getdate()),6) %C1*`"Jb&
Dateadd(mm,datediff(mm,0,getdate()),0) .dE2,9{Z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) q@@C|oqEX
Dateadd(yy,datediff(yy,0,getdate()),0) ZC!GKWP2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) H)@f_pfj(
上面的SQL代码只是一个时间段 qX_(
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Dateadd(wk,datediff(wk,0,getdate()),-1) $D%[}[2
Dateadd(wk,datediff(wk,0,getdate()),6) ,suC`)R
就是表示本周时间段. #P,C9OQD
下面的SQL的条件部分,就是查询时间段在本周范围内的: rn8#nQ>QZ%
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) sI,S(VWor
而在存储过程中 ;,&$ob*/
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `A0trC3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |to|kU