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。 D[@-`F
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一、基础 p%>!1_'(
1、说明:创建数据库 }])j>E
CREATE DATABASE database-name bt=D<YZk
2、说明:删除数据库 W3\+51P
drop database dbname Th%w-19,8
3、说明:备份sql server "[["naa
--- 创建 备份数据的 device E5P.x^
USE master : ciwh
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' otjT?R2g'
--- 开始 备份 "N%W5[C{
BACKUP DATABASE pubs TO testBack ?UflK
4、说明:创建新表 0W6='7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) cqh1,h$sG
根据已有的表创建新表: NPBOG1q%
A:create table tab_new like tab_old (使用旧表创建新表) u_ :gqvC=
B:create table tab_new as select col1,col2... from tab_old definition only Ve[Kv07
5、说明:删除新表 u8A,f}D 3
drop table tabname olo9YrHn
6、说明:增加一个列 su\Lxv
Alter table tabname add column col type p,8:(|(
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 2-g 5Gb2|
7、说明:添加主键: Alter table tabname add primary key(col) iN
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说明:删除主键: Alter table tabname drop primary key(col) CD?b.Cxai
8、说明:创建索引:create [unique] index idxname on tabname(col....) |1OF!(:
删除索引:drop index idxname }VH`\g}
注:索引是不可更改的,想更改必须删除重新建。 #CeWk$)m
9、说明:创建视图:create view viewname as select statement GZ:1bV37%
删除视图:drop view viewname Gqar5
10、说明:几个简单的基本的sql语句 K^AIqL8
选择:select * from table1 where 范围 R^I4_ZA
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 !qs~j=;y3
更新:update table1 set field1=value1 where 范围 ,`ehR6b
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ir)~T0
排序:select * from table1 order by field1,field2 [desc] !Cm9DzG
总数:select count as totalcount from table1 Z
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求和:select sum(field1) as sumvalue from table1 ~|wh/]{b9
平均:select avg(field1) as avgvalue from table1 .YS48 c
最大:select max(field1) as maxvalue from table1 5Obv/C
最小:select min(field1) as minvalue from table1 JHVesX
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11、说明:几个高级查询运算词 *zPz)3;
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A: UNION 运算符 R?,XSJ
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。 Fmrl*tr
B: EXCEPT 运算符 _3Q8R}
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。 hKK"D:?PRs
C: INTERSECT 运算符 xb(y15R\I
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。 qZ+^ND(I
注:使用运算词的几个查询结果行必须是一致的。 H 4W4#\M
12、说明:使用外连接 T
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A、left outer join: xOpCybmc
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。 v|r#
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 ATU] KL!{
B:right outer join: h IUO=f
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。 |f&=9%
C:full outer join: bU"2D.k
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。 AqP7UL
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二、提升 Q pbzx/2h
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) v4x1=E
法一:select * into b from a where 1<>1 k<NEauQ
法二:select top 0 * into b from a VbzW4J_
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o4pe>hn
insert into b(a, b, c) select d,e,f from b; V\o&{7!
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) )h?Pz1-W1
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 7q _.@J
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ::rKW*?
4、说明:子查询(表名1:a 表名2:b) tqe8:\1yK
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) &ffd#2f`@
5、说明:显示文章、提交人和最后回复时间 3DO
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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 HBnnIbEtF'
6、说明:外连接查询(表名1:a 表名2:b) jPNm $Y1
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |\~!oN
7、说明:在线视图查询(表名1:a ) <O?UC/$)7
select * from (SELECT a,b,c FROM a) T where t.a > 1; [8Zvs=1
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 eyGY8fF8$
select * from table1 where time between time1 and time2 `[Xff24(eb
select a,b,c, from table1 where a not between 数值1 and 数值2 #!X4\+)
9、说明:in 的使用方法 -F| C6m!
select * from table1 where a [not] in ('值1','值2','值4','值6') 2oFHP_HVfu
10、说明:两张关联表,删除主表中已经在副表中没有的信息 564)ha/^(
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) r|tTDKGQ
11、说明:四表联查问题: KoNJ;YiKtN
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 ..... sC.aT(meJ
12、说明:日程安排提前五分钟提醒 Bzw!,(u/
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 -?$Hr\
13、说明:一条sql 语句搞定数据库分页 2,X~a;+
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 #A2)]XvY
14、说明:前10条记录 m:7$"oq|
select top 10 * form table1 where 范围 MdOQEWJ$|
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) '4nR ^,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -C|1O%.
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ZsPT!l,
(select a from tableA ) except (select a from tableB) except (select a from tableC) C&vUZa[p
17、说明:随机取出10条数据 q^_PR|
select top 10 * from tablename order by newid() ?x(]U+
18、说明:随机选择记录 / b_C9'S
select newid() dt(#|8i%
19、说明:删除重复记录 OA_Bz"
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2=TQU33#
20、说明:列出数据库里所有的表名 DhwFD8tT
select name from sysobjects where type='U' l25E!E-'b
21、说明:列出表里的所有的 #q"^6C
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select name from syscolumns where id=object_id('TableName') c.u$NnDU6
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。 ^$7Lmd.qI
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 '@ym-\,
显示结果: MW^,l=kqW)
type vender pcs ^nYS@
电脑 A 1 n'yC- ;
电脑 A 1 ix<sorR H
光盘 B 2 "?Eh_Dw
光盘 A 2 8#9di
手机 B 3 <303PPX^6
手机 C 3 3:f<cy
23、说明:初始化表table1 \o-Q9V
TRUNCATE TABLE table1 #[^?f[9r
24、说明:选择从10到15的记录 )pS1yYLj
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Cw<bu|?
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三、技巧 !4 4 )=xW
1、1=1,1=2的使用,在SQL语句组合时用的较多 z:hY{/-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 7.n/W|\
如: li4rK<O
if @strWhere !='' $z!o&3c'x
begin Q7X6OFl?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X&1R6O
end e~C^*w L
else uUUj?%
begin OTA @4~{C
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Y|t] bb
end ;?>xuC$
我们可以直接写成 !@9Vq6
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere (Yz EsY
2、收缩数据库 Ux~rBv''
--重建索引 *~F\k):>
DBCC REINDEX sT"U}
DBCC INDEXDEFRAG wf!?'*
--收缩数据和日志 `)`J
DBCC SHRINKDB @B;2z_Y!l
DBCC SHRINKFILE $=7[.z&
3、压缩数据库 TFbMrIF
dbcc shrinkdatabase(dbname) ^YddVp
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' hr&&"d {s
go ^EGe%Fq*x]
5、检查备份集 0oI3Fb;E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^2L\Y2
6、修复数据库 X\tE#c&K
ALTER DATABASE [dvbbs] SET SINGLE_USER gTE/g'3
GO {_0m0
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?\MvAG7Y
GO -lr)z=})
ALTER DATABASE [dvbbs] SET MULTI_USER \2(Uqf#_
GO rPoPs@CBD
7、日志清除 F-?K]t#
SET NOCOUNT ON a?bSMt}
DECLARE @LogicalFileName sysname, C~PrIM?
@MaxMinutes INT, -1Acprr
@NewSize INT w]b3,b
USE tablename -- 要操作的数据库名 gs)wQgJ [
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t\J5np
@MaxMinutes = 10, -- Limit on time allowed to wrap log. okfGd=
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@NewSize = 1 -- 你想设定的日志文件的大小(M) X{A|{ u=
-- Setup / initialize (Zi(6 T\z
DECLARE @OriginalSize int \}SA{)
SELECT @OriginalSize = size S(kj"t*3
FROM sysfiles 0d!1;jy,T
WHERE name = @LogicalFileName p=m) lR9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + R I Bj9kd
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + T#'+w@Q9{9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' n82N@z<8]
FROM sysfiles FB{4& ;
WHERE name = @LogicalFileName G8%Q$
CREATE TABLE DummyTrans {3@lvoDT
(DummyColumn char (8000) not null) UxI0Of&:
DECLARE @Counter INT, dI'cZt~n
@StartTime DATETIME, ?4%'6R
@TruncLog VARCHAR(255) [t@
SELECT @StartTime = GETDATE(), <rd7<@>5D
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <k)@PAV
DBCC SHRINKFILE (@LogicalFileName, @NewSize) P@P(&{@
EXEC (@TruncLog) g_?:G$1H
-- Wrap the log if necessary. #g,JNJ}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired RD_IGV
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Ei!5Qya>
AND (@OriginalSize * 8 /1024) > @NewSize 16"eyt>
BEGIN -- Outer loop. SE=3`rVJ
SELECT @Counter = 0 :7ej6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) o:E+c_^q`
BEGIN -- update .a._WZF
INSERT DummyTrans VALUES ('Fill Log') ~A<1xszC
DELETE DummyTrans @T53%v<5
SELECT @Counter = @Counter + 1 sM)qzO2wh
END :A%|'HxH3
EXEC (@TruncLog) ,c#IxB/0
END [iE% P^
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,H!E :k
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =fmM=@!$<
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q]F2bo
FROM sysfiles <eRE;8C-
WHERE name = @LogicalFileName My'u('Q%
DROP TABLE DummyTrans )G$/II9d
SET NOCOUNT OFF t,#9i#q#
8、说明:更改某个表 ycAQHY~n
exec sp_changeobjectowner 'tablename','dbo' rjzRZ
9、存储更改全部表 gf/$M[H!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 69{^Vfd;Y
@OldOwner as NVARCHAR(128), -V@vY42
@NewOwner as NVARCHAR(128) +*"u(7AV
AS JSXudz5c
DECLARE @Name as NVARCHAR(128) nO^aZmSu
DECLARE @Owner as NVARCHAR(128) "&;>l<V
DECLARE @OwnerName as NVARCHAR(128) f\CJ |tKX
DECLARE curObject CURSOR FOR wi'CBfr'z
select 'Name' = name, 0M^7#),
'Owner' = user_name(uid) _[ml<HW]
from sysobjects f0rM 4"1
where user_name(uid)=@OldOwner ^_FB .y%
order by name ^|yw)N]Q/
OPEN curObject s=0z%~H
FETCH NEXT FROM curObject INTO @Name, @Owner -*8 |J;
WHILE(@@FETCH_STATUS=0) }Z5f5q
BEGIN k<p$BZ
if @Owner=@OldOwner 4/Ub%t-
begin -a:+ h\K
set @OwnerName = @OldOwner + '.' + rtrim(@Name) o HqBNTyH
exec sp_changeobjectowner @OwnerName, @NewOwner EA.4m3
end LE^kN<qMK
-- select @name,@NewOwner,@OldOwner W]E6<y'
FETCH NEXT FROM curObject INTO @Name, @Owner ,B|~V 3)(
END 7x8/Vz@\
close curObject oujg(
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deallocate curObject Cf@~W)K
GO Le#>uWM
10、SQL SERVER中直接循环写入数据 ,CiN@T \&
declare @i int 0XV8B
set @i=1 ,PH ;j_
while @i<30 OwXw9
begin &AR@5M u
insert into test (userid) values(@i) ? <b>2j
set @i=@i+1 l-` M
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end y[M<x5
小记存储过程中经常用到的本周,本月,本年函数 13
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Dateadd(wk,datediff(wk,0,getdate()),-1) AlP}H~|M7
Dateadd(wk,datediff(wk,0,getdate()),6) sPMCN's
Dateadd(mm,datediff(mm,0,getdate()),0) wLn,x;;<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) UI S\t^pJD
Dateadd(yy,datediff(yy,0,getdate()),0) V$U#'G>m
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %j3XoRex><
上面的SQL代码只是一个时间段 Ox.6]W~
Dateadd(wk,datediff(wk,0,getdate()),-1) z ((Y \vP
Dateadd(wk,datediff(wk,0,getdate()),6) ;S
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就是表示本周时间段. (+SfDL$m
下面的SQL的条件部分,就是查询时间段在本周范围内的: e}%~S9\UL5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) #{-l(016y
而在存储过程中 *E$&
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 38<!Dt+S(,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xgsE JE