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。 1&
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一、基础 BK'!WX
1、说明:创建数据库 Dc[Qu?]LM
CREATE DATABASE database-name .Wq`qF(;
2、说明:删除数据库 WQ]~TGW
drop database dbname 8<t?o'9I
3、说明:备份sql server rY>{L6d
--- 创建 备份数据的 device XRI1/2YA
USE master {A(=phN
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' iw(\]tMt
--- 开始 备份 F^=|NlU&%
BACKUP DATABASE pubs TO testBack 3X{=*wvt
4、说明:创建新表 >=2nAv/(
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) J|Lk::Ri
根据已有的表创建新表: NDRk%_Eu(
A:create table tab_new like tab_old (使用旧表创建新表) Wv"[,5
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B:create table tab_new as select col1,col2... from tab_old definition only (0qdU;
5、说明:删除新表 'B"kUh%3$5
drop table tabname %xR;8IO
6、说明:增加一个列 3Nh;^
Alter table tabname add column col type fwI Zr~l
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 M)#R_(Q5{
7、说明:添加主键: Alter table tabname add primary key(col) N2}].}
说明:删除主键: Alter table tabname drop primary key(col) ?|:!PF*L~z
8、说明:创建索引:create [unique] index idxname on tabname(col....) '8>#`Yba
删除索引:drop index idxname H+; _fd
注:索引是不可更改的,想更改必须删除重新建。 %+G/oF|
9、说明:创建视图:create view viewname as select statement dox QS ohS
删除视图:drop view viewname S&V5zB""n
10、说明:几个简单的基本的sql语句 oS$&jd
选择:select * from table1 where 范围 cJm!3X
插入:insert into table1(field1,field2) values(value1,value2) odquAqn
删除:delete from table1 where 范围 =? x A*_^
更新:update table1 set field1=value1 where 范围 H#G~b""mY
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6kjBd3
排序:select * from table1 order by field1,field2 [desc] Gr#p QE2;
总数:select count as totalcount from table1 awXL}m[_!
求和:select sum(field1) as sumvalue from table1 A{;b^IK
平均:select avg(field1) as avgvalue from table1 /+J?Ep(_
最大:select max(field1) as maxvalue from table1 D;<Qm,[
最小:select min(field1) as minvalue from table1 >.#uoW4ZV
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11、说明:几个高级查询运算词 g?i_10Xlp
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A: UNION 运算符 KI$?0O
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。 i<1w*yu
B: EXCEPT 运算符 ^?toTU
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。 $RKd@5XP
C: INTERSECT 运算符 7s5?^^
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ;oULtQ
注:使用运算词的几个查询结果行必须是一致的。 C|W_j&S65
12、说明:使用外连接 89@89-_mC
A、left outer join: 5<a)SP 0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 (J<@e!@NE
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c dp2".
B:right outer join: ~@bCSOIy
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 r#]gAG4t\
C:full outer join: =X>3C"]
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 9))%tYN
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二、提升 J(M0t~RZ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +]CKu$,8
法一:select * into b from a where 1<>1 akBR"y:~:H
法二:select top 0 * into b from a c1CP12
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %o#D"
insert into b(a, b, c) select d,e,f from b; [gzw<b:`
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) ui7 0|
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 BaiC;&(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. N!"GwH
4、说明:子查询(表名1:a 表名2:b) #JO#PV%
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) 5]p>&|Ud
5、说明:显示文章、提交人和最后回复时间 }PyAmh$@
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ua V9T:)x
6、说明:外连接查询(表名1:a 表名2:b) D/{Tl
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *xU^e`P
7、说明:在线视图查询(表名1:a ) DD|%F
select * from (SELECT a,b,c FROM a) T where t.a > 1; ))G%C6-
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Y: KB"H
select * from table1 where time between time1 and time2 jfqWcX.X=
select a,b,c, from table1 where a not between 数值1 and 数值2 tmK@Veb*a'
9、说明:in 的使用方法 ,$vc*}yI0
select * from table1 where a [not] in ('值1','值2','值4','值6') w*#k&N[X
10、说明:两张关联表,删除主表中已经在副表中没有的信息 c2?(.UV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RURO0`^
11、说明:四表联查问题: U`:#+8h-}
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 ..... +VDl"Hx
12、说明:日程安排提前五分钟提醒 Ej 'a
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]v94U b
13、说明:一条sql 语句搞定数据库分页 Ax0u \(p<^
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 #B`"B
14、说明:前10条记录 -&))$h3o\
select top 10 * form table1 where 范围 na
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) !j %)nU
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~LO MwMHl
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 xfO!v>
(select a from tableA ) except (select a from tableB) except (select a from tableC) M29[\@zL
17、说明:随机取出10条数据 )/bt/,M&}
select top 10 * from tablename order by newid() og.dYs7W4
18、说明:随机选择记录 U@m<
select newid() cdzzS?$)
19、说明:删除重复记录 )5d&K8@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) N;-+)=M,rf
20、说明:列出数据库里所有的表名 ;N ]ElwP
select name from sysobjects where type='U' &E {/s
21、说明:列出表里的所有的 8dIgw
select name from syscolumns where id=object_id('TableName') }Ss#0Gee
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。 %Dsa
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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 c4L5"_#`x-
显示结果: ,UWO+B]
type vender pcs xE;fM\7pu
电脑 A 1 xC<OFpI\
电脑 A 1 JZu7Fb]L9
光盘 B 2 vh?({A#>.E
光盘 A 2 ^"6xE nA]
手机 B 3 U G^6I5
手机 C 3 pl
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23、说明:初始化表table1 "M_X9n_
TRUNCATE TABLE table1 5>}L3r>a;
24、说明:选择从10到15的记录 {x2N~1!E
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |;rjr_I
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三、技巧 CXCU5-
1、1=1,1=2的使用,在SQL语句组合时用的较多 3iH!;`i
"where 1=1" 是表示选择全部 "where 1=2"全部不选, _~Lhc'^p*
如: SAThY$)6
if @strWhere !='' z56W5g2
begin H -.3r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere s'~_pP
end K.l?R#G`,F
else 2',t@< U
begin mtm BL2?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 6<]&T lS]
end vhWj_\m
我们可以直接写成 SGNi~o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere vx!nC}f"k`
2、收缩数据库 ET=q
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--重建索引 oPzt1Y
DBCC REINDEX b LL!iz?
DBCC INDEXDEFRAG 6],5X^*Y
--收缩数据和日志 )_xM)mH
DBCC SHRINKDB QhpE 2ICU
DBCC SHRINKFILE T`a [~:
3、压缩数据库 Uy_`=JZ
dbcc shrinkdatabase(dbname) Am kHVg
4、转移数据库给新用户以已存在用户权限 VD36ce9
exec sp_change_users_login 'update_one','newname','oldname' bB)EJCPq>
go O_F<VV*MFQ
5、检查备份集 ?>RJ8\Sj
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' P>4(+s
6、修复数据库 ^U~YG=!ww
ALTER DATABASE [dvbbs] SET SINGLE_USER bG.aV#$FIg
GO ;K$E;ZhPN
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK r(cS{oni
GO ,"j|0Q
ALTER DATABASE [dvbbs] SET MULTI_USER J"6_H =s
GO %@H;6
7、日志清除 f*oL8"?u&
SET NOCOUNT ON & r\z9!
DECLARE @LogicalFileName sysname, ub,Sj{Mq"
@MaxMinutes INT, rf)\:75
@NewSize INT N<N!it
USE tablename -- 要操作的数据库名 tV#x{DN
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 )
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. |!57Z4X
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1!vR
8.
-- Setup / initialize UnW,|n8
DECLARE @OriginalSize int \8_&@uLm
SELECT @OriginalSize = size .f(x9|K^
FROM sysfiles ~73YOGiGJH
WHERE name = @LogicalFileName Fo;xA
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,a5I:V^\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #<v3G)|aS
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g~10K^
FROM sysfiles *(o~pxFTR
WHERE name = @LogicalFileName lW^RwNcd
CREATE TABLE DummyTrans n~K_|
(DummyColumn char (8000) not null) s=U_tfpH
DECLARE @Counter INT, /7P4[~vw
@StartTime DATETIME, U&`M G1uHe
@TruncLog VARCHAR(255) gR~XkU
SELECT @StartTime = GETDATE(), 42#
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' nBGk %NM 8
DBCC SHRINKFILE (@LogicalFileName, @NewSize) HK:?Y[ebs
EXEC (@TruncLog) _4.`$n/Z
-- Wrap the log if necessary. JRU)AMMU&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #1V vK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) RE*UIh*O
AND (@OriginalSize * 8 /1024) > @NewSize 7*@qd&
BEGIN -- Outer loop. EVRg/{X
SELECT @Counter = 0 ]'T-6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) nW{7L
BEGIN -- update 6AZ/whn#
INSERT DummyTrans VALUES ('Fill Log') 6\b B#a
DELETE DummyTrans Q !S"=2
SELECT @Counter = @Counter + 1 Y}nE/bmx&9
END --
_,;
EXEC (@TruncLog) |3"'>*
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END rC/m}`b
SELECT 'Final Size of ' + db_name() + ' LOG is ' + kS=OX5
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lm]4zs /A
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' zy+|)^E
FROM sysfiles +s1mm c
WHERE name = @LogicalFileName WI}P(!h\J
DROP TABLE DummyTrans W~dS8B=<
SET NOCOUNT OFF U.?,vw'aai
8、说明:更改某个表 g-Z>1V
exec sp_changeobjectowner 'tablename','dbo' mNcTO0p&
9、存储更改全部表 v0=^Hym
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch uN6TV*]:
@OldOwner as NVARCHAR(128), f5d"H6%L
@NewOwner as NVARCHAR(128) S
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AS qBKIl=
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DECLARE @Name as NVARCHAR(128) ETjlq]@j
DECLARE @Owner as NVARCHAR(128) Os?~U/
DECLARE @OwnerName as NVARCHAR(128) 8BLtTpu
DECLARE curObject CURSOR FOR IY,&/MCh
select 'Name' = name, \gj@O5rG P
'Owner' = user_name(uid) -i?!em'J
from sysobjects XP6R$0yN
where user_name(uid)=@OldOwner dbE $T
order by name e[w)U{|40
OPEN curObject DghX(rs_
FETCH NEXT FROM curObject INTO @Name, @Owner e~nmIy
WHILE(@@FETCH_STATUS=0) 0gfa7+Y
BEGIN 9$UjZ$ v
if @Owner=@OldOwner ldi'@^
begin G~u94rw|:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~i6tcd
exec sp_changeobjectowner @OwnerName, @NewOwner u -CY-
end @ZD1HA,h"
-- select @name,@NewOwner,@OldOwner nmS3
FETCH NEXT FROM curObject INTO @Name, @Owner tY%c-m
END |2{y'?,
close curObject IqcPml{\
deallocate curObject q9icj
GO Uhb6{'+
10、SQL SERVER中直接循环写入数据 & UL(r
declare @i int T4o}5sq}S
set @i=1 XSn^$$S
while @i<30 9[6xo!
begin 1&Nk
insert into test (userid) values(@i) r`B8Cik
set @i=@i+1 Dr,{V6^
end ryN/sjQC
小记存储过程中经常用到的本周,本月,本年函数 2/qfK+a
Dateadd(wk,datediff(wk,0,getdate()),-1) p24sWDf
Dateadd(wk,datediff(wk,0,getdate()),6) 1th|n
Dateadd(mm,datediff(mm,0,getdate()),0) Fu{[5uv
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yxLGseD
Dateadd(yy,datediff(yy,0,getdate()),0) MDl
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1ciP+->$
上面的SQL代码只是一个时间段 s26:(J
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Dateadd(wk,datediff(wk,0,getdate()),-1) 7cY_=X-?Y
Dateadd(wk,datediff(wk,0,getdate()),6) 'zi5ihiT
就是表示本周时间段. m:II<tv
下面的SQL的条件部分,就是查询时间段在本周范围内的: tlI3jrgw
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,?<jue/bd
而在存储过程中 ;:8_H0X'K
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >L?/Ph %d
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) UH.M)br