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。 e 3>k"
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一、基础 v6?<)M%
1、说明:创建数据库 ,K[B/tD{j
CREATE DATABASE database-name }~5xlg$B<<
2、说明:删除数据库 K#{E87G(
drop database dbname ]H<C Rw
3、说明:备份sql server 8JAT2a61ur
--- 创建 备份数据的 device l@YpgyqaL
USE master #$%gs]
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Wkv**X}
--- 开始 备份 Afa{f}st
BACKUP DATABASE pubs TO testBack X]*W +
4、说明:创建新表 )O%lh
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9uREbip
根据已有的表创建新表: u]cnbm
A:create table tab_new like tab_old (使用旧表创建新表) UoxF00H@!
B:create table tab_new as select col1,col2... from tab_old definition only s^{j
5、说明:删除新表 9~mi[l~
drop table tabname `0Q:d'
6、说明:增加一个列 7+u%]D!
Alter table tabname add column col type OiY2l;68
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。 0?t!tugG
7、说明:添加主键: Alter table tabname add primary key(col) ArU>./)Q
说明:删除主键: Alter table tabname drop primary key(col) P-`^I`r
8、说明:创建索引:create [unique] index idxname on tabname(col....) osX23T~-
删除索引:drop index idxname YKvFZH)
注:索引是不可更改的,想更改必须删除重新建。 I_ .;nU1xA
9、说明:创建视图:create view viewname as select statement w }2|Do$5
删除视图:drop view viewname T}]Ao
10、说明:几个简单的基本的sql语句 (A&@
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选择:select * from table1 where 范围 0KT{K(
插入:insert into table1(field1,field2) values(value1,value2) c\4n 7m,y
删除:delete from table1 where 范围 iVu+ct-iv
更新:update table1 set field1=value1 where 范围 z?"5="D
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! NI s4v(!
排序:select * from table1 order by field1,field2 [desc] MgMLfgt"V
总数:select count as totalcount from table1 7<^D7
求和:select sum(field1) as sumvalue from table1 KwQO,($,]
平均:select avg(field1) as avgvalue from table1 )SUN+YV^
最大:select max(field1) as maxvalue from table1 Q84KU8?d
最小:select min(field1) as minvalue from table1 W{m0z+N[B
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11、说明:几个高级查询运算词 v
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A: UNION 运算符 %#QFu/l
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。 v,i:vT\~
B: EXCEPT 运算符 kdYl>M
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。 #1bgV
C: INTERSECT 运算符 g&E_|}u4
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。 M9OFK\)
注:使用运算词的几个查询结果行必须是一致的。 -6tF
12、说明:使用外连接 M<~F>(wxA
A、left outer join: NxX1_d
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。 N[+dX_h
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
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B:right outer join: usTCn3u
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。 V!<#E)-?<
C:full outer join: My`%gP~%g
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。 ToJru
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二、提升 $^0YK|F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Csc2 yI%3
法一:select * into b from a where 1<>1 1aT$07G0
法二:select top 0 * into b from a d|NNIf
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d<3"$%C
insert into b(a, b, c) select d,e,f from b; z"O-d<U5
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 #OU {2X
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [1UqMkXtf
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 6kuSkd$.
4、说明:子查询(表名1:a 表名2:b) $WPN.,7
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) !aEp88u
5、说明:显示文章、提交人和最后回复时间 V7@xr
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9,c>H6R7
6、说明:外连接查询(表名1:a 表名2:b) HYH!;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?3Fo:Z`@F
7、说明:在线视图查询(表名1:a ) NR[mzJv
select * from (SELECT a,b,c FROM a) T where t.a > 1; n|*V
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 E37@BfpO3
select * from table1 where time between time1 and time2 &L?Dogo
select a,b,c, from table1 where a not between 数值1 and 数值2 7f$Lb,\y
9、说明:in 的使用方法 5~X%*_[],
select * from table1 where a [not] in ('值1','值2','值4','值6') )yK!qu
10、说明:两张关联表,删除主表中已经在副表中没有的信息 I^|bQ3sor
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) } R/
11、说明:四表联查问题: W[m_IY
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 ..... dCK-"#T!
12、说明:日程安排提前五分钟提醒 HY:@=%R
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |#B"j1D,H
13、说明:一条sql 语句搞定数据库分页 T:&+#0<
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 qpeK><o
14、说明:前10条记录 *3K"Kc2
select top 10 * form table1 where 范围 #?=cg]v_
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.) ,'673PR
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) FS}z_G|4]
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 +J4t0x
(select a from tableA ) except (select a from tableB) except (select a from tableC) %dU}GYL_
17、说明:随机取出10条数据 >dl!Ep
select top 10 * from tablename order by newid() ({9!P30:
18、说明:随机选择记录 ?f`-&c;
select newid() F1=+<]!
19、说明:删除重复记录 HW G~m:km
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) S_CtEM
20、说明:列出数据库里所有的表名 YC_^jRB8n
select name from sysobjects where type='U' FTfA\/tl(;
21、说明:列出表里的所有的 u@EM,o
select name from syscolumns where id=object_id('TableName') {EUH#':
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。 D.6dPzu`
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 xVyUUzXs
显示结果: p o`$^TB^+
type vender pcs lBdF9F<
电脑 A 1 KV*:,>
电脑 A 1 B# fzMaC
光盘 B 2 I@ k8^
光盘 A 2 Jq#Cn+zW
手机 B 3 F%d"gF0qu
手机 C 3 ;^*!<F%t9R
23、说明:初始化表table1 {ybuHC
TRUNCATE TABLE table1 iPOZ{'Z
24、说明:选择从10到15的记录 dL`
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &3f.78a
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三、技巧 >i%w'uU
1、1=1,1=2的使用,在SQL语句组合时用的较多 t>2^!vl
"where 1=1" 是表示选择全部 "where 1=2"全部不选, | dwxea
如: eNFUjDm
if @strWhere !='' ODEXQl}R
begin &^_(xgJL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere (O2HB-<rY
end eeZysCy+DY
else N0[I2'^.
begin Ol9fwd
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 36a~!
end PuJ{!S\T7
我们可以直接写成 7nz+n#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere { NJ>[mKg
2、收缩数据库 9VE;I:NO3
--重建索引 H@ms43v\
DBCC REINDEX QP%Fz#u`
DBCC INDEXDEFRAG ..!-)q'?
--收缩数据和日志 X^5"7phI@
DBCC SHRINKDB ? myXG92
DBCC SHRINKFILE Zbh]OCN
3、压缩数据库 8$kXC+
dbcc shrinkdatabase(dbname) ~N^vE;
4、转移数据库给新用户以已存在用户权限 5ba[6\Af
exec sp_change_users_login 'update_one','newname','oldname' wWU_?Dr_~
go znO00qX
5、检查备份集 dt+
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &R*5;/
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6、修复数据库 S "Pj1
ALTER DATABASE [dvbbs] SET SINGLE_USER wPJRp]FA
GO #cG479X"
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK [B3aRi0AQ
GO BpG'e-2
ALTER DATABASE [dvbbs] SET MULTI_USER FT>~ES]cQd
GO TrU@mYnE
7、日志清除 je4&'vyU
SET NOCOUNT ON D!a5#+\C
DECLARE @LogicalFileName sysname, q{/Jw"e
@MaxMinutes INT, 5Y=\~,%\oH
@NewSize INT t=rAcyNM
USE tablename -- 要操作的数据库名 U/!&KsnT
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _|B&v
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (iOCzZ6S
@NewSize = 1 -- 你想设定的日志文件的大小(M) gQ[^gPWP"
-- Setup / initialize kO_XyC4(
DECLARE @OriginalSize int N"RYM~c7
SELECT @OriginalSize = size K]!u@I* K"
FROM sysfiles 'Q>z**
WHERE name = @LogicalFileName psX%.95Y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + aiZo{j<6
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0"psKf'
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @1?]$?u&
FROM sysfiles [Cqqjv;_
WHERE name = @LogicalFileName uQ]]]Z(H'
CREATE TABLE DummyTrans 36x:(-GFq
(DummyColumn char (8000) not null) Vnj/>e3
DECLARE @Counter INT, *X
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@StartTime DATETIME, }FiN 7#
@TruncLog VARCHAR(255) ,i?!3oLT
SELECT @StartTime = GETDATE(), :n9xH
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' KzX
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) E(!6n= qR
EXEC (@TruncLog) Z#6~N/b
-- Wrap the log if necessary. C%_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T#G<?oF
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) - (_e=3$
AND (@OriginalSize * 8 /1024) > @NewSize p?$G>nkdq
BEGIN -- Outer loop. R:OU>HsdX
SELECT @Counter = 0 } .3]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) QrckTO
BEGIN -- update `XSc >
INSERT DummyTrans VALUES ('Fill Log') )6:]o&bZ
DELETE DummyTrans Lv5X 'yM
SELECT @Counter = @Counter + 1 aZjef
END 2\63&C^
EXEC (@TruncLog) f\);HJbg
END M"5!s,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + kq%gY
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + P%@rH@^Y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' =Xy`"i{`(
FROM sysfiles Z1$];Q\cX
WHERE name = @LogicalFileName XMEK5Z9Dd
DROP TABLE DummyTrans fb"J Bc}X
SET NOCOUNT OFF 6~F#F)C'
8、说明:更改某个表 "bR'Bt
exec sp_changeobjectowner 'tablename','dbo' |\%F(d330
9、存储更改全部表 3> \fP#oQ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ,+/9K)X
@OldOwner as NVARCHAR(128), [Ba2b: l6v
@NewOwner as NVARCHAR(128) W`u$7k]$
AS {LT4u]#
DECLARE @Name as NVARCHAR(128) _TOi
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DECLARE @Owner as NVARCHAR(128) y,v0-o~q
DECLARE @OwnerName as NVARCHAR(128) <L/M`(:=k
DECLARE curObject CURSOR FOR XK%W^a*x
select 'Name' = name, }or2 $\>m
'Owner' = user_name(uid) L+L"$
from sysobjects `Ixs7{&jU
where user_name(uid)=@OldOwner #K#Mv/
order by name -|Yh/
OPEN curObject +t>*l>[
FETCH NEXT FROM curObject INTO @Name, @Owner P
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WHILE(@@FETCH_STATUS=0) Y$x"4=~
BEGIN R] Disljq
if @Owner=@OldOwner A3"1D
begin umm \r&]A
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +#*&XX5A#?
exec sp_changeobjectowner @OwnerName, @NewOwner kQwm"Z
end +2EHmuJ;
-- select @name,@NewOwner,@OldOwner ]D{c4)\7C|
FETCH NEXT FROM curObject INTO @Name, @Owner Bn1L?>G
END r}R^<y@I
close curObject dqD;y#/
deallocate curObject E#<7\p>
GO EvqUNnjR
10、SQL SERVER中直接循环写入数据 18.Y/nZAgQ
declare @i int f^!11/Wv
set @i=1 W1?!iE~tO
while @i<30 2{mY:\
begin z [qdmx^
insert into test (userid) values(@i) ?-8y4
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set @i=@i+1 "J P{Q
end 3s?v(1 {)
小记存储过程中经常用到的本周,本月,本年函数 _b0S
Dateadd(wk,datediff(wk,0,getdate()),-1) C|4U78f{
Dateadd(wk,datediff(wk,0,getdate()),6) &@4.;u
Dateadd(mm,datediff(mm,0,getdate()),0) NWJcFj_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) p*pn@z
Dateadd(yy,datediff(yy,0,getdate()),0) QT1:>k
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~VqFZasV
上面的SQL代码只是一个时间段 yX7CN5vVl
Dateadd(wk,datediff(wk,0,getdate()),-1) }c`
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Dateadd(wk,datediff(wk,0,getdate()),6) #)_J)/h
就是表示本周时间段. _8[UtZYG
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^e?$ ]JiA!
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) C~ZE95g
而在存储过程中 3VcT7y*{P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) X)Dqeb6
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) UsLh)#}h