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。 V'{\g|)
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一、基础 l+ >eb
1、说明:创建数据库 JMt*GFd
CREATE DATABASE database-name OS;
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2、说明:删除数据库 @:Zk,
drop database dbname %H\J@{f
3、说明:备份sql server }NyQ<,+mq&
--- 创建 备份数据的 device 6Ot~Q
USE master {aUTTEu
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0D 2I)E72o
--- 开始 备份 Dh8'og)7
BACKUP DATABASE pubs TO testBack siI%6Gn;
4、说明:创建新表 `WXlq#:K
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h-1?c\Qq:
根据已有的表创建新表: =3(Auchl$Y
A:create table tab_new like tab_old (使用旧表创建新表) F^bY]\-5
B:create table tab_new as select col1,col2... from tab_old definition only {*B0lr`
5、说明:删除新表 v
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drop table tabname ;DK%!."%
6、说明:增加一个列 DNq(\@x[!
Alter table tabname add column col type s*la`(x
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 u*Xp%vNe
7、说明:添加主键: Alter table tabname add primary key(col) &
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说明:删除主键: Alter table tabname drop primary key(col) 1}a4AGAp
8、说明:创建索引:create [unique] index idxname on tabname(col....) (&eF E ;c
删除索引:drop index idxname t}_ #N'`
注:索引是不可更改的,想更改必须删除重新建。 Godrz*"
9、说明:创建视图:create view viewname as select statement =W3
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删除视图:drop view viewname Dj96t5R
10、说明:几个简单的基本的sql语句 ) %Fwfb
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) 24#qg'
删除:delete from table1 where 范围 L>~Tc
更新:update table1 set field1=value1 where 范围 )L:e0u
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1X5g(B
排序:select * from table1 order by field1,field2 [desc] JXJ+lZmsz
总数:select count as totalcount from table1 ^C'0Y.H S
求和:select sum(field1) as sumvalue from table1 :+Ukwno?/
平均:select avg(field1) as avgvalue from table1 1V1I[CxlX
最大:select max(field1) as maxvalue from table1 =${.*,o
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 -sQ[f18
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A: UNION 运算符 `Fn"QL-
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。 IANSpWea?
B: EXCEPT 运算符 o0 C&ol_
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。 1]G)41
C: INTERSECT 运算符 q_.fVn:!
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。 d:';s~
注:使用运算词的几个查询结果行必须是一致的。 m@Yc&M~
12、说明:使用外连接 \i_E}Ii0
A、left outer join: VGQ~~U7}@
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。 @Iz]:@\cJ
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 uTR^K=Ve
B:right outer join: 95mf
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。 j-ej7
C:full outer join: -n05Z@7
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。 C*(
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二、提升 |2q3spd
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) AVpg
法一:select * into b from a where 1<>1 ]Orx%8QS!
法二:select top 0 * into b from a d>hv-nD
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) g.Xk6"kO
insert into b(a, b, c) select d,e,f from b; %)r ~GCd
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) r+FEgSDa]
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Kb?{^\FiU
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. vt#;j;liG
4、说明:子查询(表名1:a 表名2:b) w95M
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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) uMg\s\Z
5、说明:显示文章、提交人和最后回复时间 d5m-f/
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _Ub
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6、说明:外连接查询(表名1:a 表名2:b) !e|\1v'0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !B3TLeh
7、说明:在线视图查询(表名1:a ) ls@]%pz.1d
select * from (SELECT a,b,c FROM a) T where t.a > 1; R
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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 U7s$';y"%
select * from table1 where time between time1 and time2
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select a,b,c, from table1 where a not between 数值1 and 数值2 >u$8Z
9、说明:in 的使用方法 SQ>i:D;
select * from table1 where a [not] in ('值1','值2','值4','值6') SL4?E<Jb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 qG6s.TcG
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) d<a|dwAeh
11、说明:四表联查问题: O{LCHtN
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... '}_r/l]K
12、说明:日程安排提前五分钟提醒 C27:tyV
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {]^Ixm-,f
13、说明:一条sql 语句搞定数据库分页 }S/i3$F0~
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 1]7gYNzV"
14、说明:前10条记录 ]P?<2,
select top 10 * form table1 where 范围 -G,}f\Cg
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.) lxhb)]c
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $6"(t= %{
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 /d3Jd.l!
(select a from tableA ) except (select a from tableB) except (select a from tableC) OT{"C"%5t
17、说明:随机取出10条数据 *1dDs^D#|
select top 10 * from tablename order by newid() ~ skp}g]
18、说明:随机选择记录 P"vrYom
select newid() 3xChik{
19、说明:删除重复记录 A;TP~xq\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [r/zBF-.
20、说明:列出数据库里所有的表名 TQ4@|S:OF
select name from sysobjects where type='U' {6'Xz
21、说明:列出表里的所有的 L|'^P3#7`
select name from syscolumns where id=object_id('TableName') Z4] n<~o
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 }g}Eh>U
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type !a@)6or
显示结果: ,S-h~x
type vender pcs w"^h<]b
电脑 A 1 9"P|Csj
电脑 A 1 dVQ[@u1,
光盘 B 2
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光盘 A 2 e,U:H~+]
手机 B 3 ]Ox5F@
手机 C 3 .;?!I_`
23、说明:初始化表table1 eTuqK23
TRUNCATE TABLE table1 UD.bb
24、说明:选择从10到15的记录 r`O
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0*$w(*
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三、技巧 5f-b>=02
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^dQ{vL@9b9
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8+F5n!
如: Kw
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if @strWhere !='' 4yl{:!la
begin i>F=XE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3P
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end Z?axrGmg0
else hS]w
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begin ~G!JqdKJ0
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' YlHP:ZW-cu
end 1 R5pf
我们可以直接写成 ZwmucY%3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere -#|D>
2、收缩数据库 NQ9v[gv
--重建索引 kka5=u
DBCC REINDEX H9cPtP~a)
DBCC INDEXDEFRAG @]=40Yj~w
--收缩数据和日志 ks4`h>i
DBCC SHRINKDB L|=5jn9 :
DBCC SHRINKFILE jJ,_-ui
3、压缩数据库 6Z2 ,:j;
dbcc shrinkdatabase(dbname) 7GgZ: $d
4、转移数据库给新用户以已存在用户权限 $83B10OQ&L
exec sp_change_users_login 'update_one','newname','oldname' '/W$9jm
go g68p9#G
5、检查备份集 )[Y B&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %M(RV_R+6
6、修复数据库 c3vb~l)
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO r"7n2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4DA34m(
GO b9.M'P\
ALTER DATABASE [dvbbs] SET MULTI_USER 5~*)3z^V
GO pCIzpEsRs
7、日志清除 >L7s[vKn
SET NOCOUNT ON ^J'_CA
DECLARE @LogicalFileName sysname, / ;]5X
@MaxMinutes INT, ht3.e[%'b
@NewSize INT rpR${%jc
USE tablename -- 要操作的数据库名 }#XFa#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ,WT>"9+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }Z!D?(
@NewSize = 1 -- 你想设定的日志文件的大小(M) )g0fN+Mb
-- Setup / initialize {0zn~+
DECLARE @OriginalSize int OZ[ YB
SELECT @OriginalSize = size Yd^@Ei9
FROM sysfiles 9njwAKF?
WHERE name = @LogicalFileName !gsvF\XDM
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^kez]>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + rd%%NnT"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *IG$"nu
FROM sysfiles ]\$/:f-2
WHERE name = @LogicalFileName +#W94s~0V
CREATE TABLE DummyTrans {MUB4-@?F$
(DummyColumn char (8000) not null) r~4uIUE{
DECLARE @Counter INT, 7u):J
@StartTime DATETIME, zzqJeIS
@TruncLog VARCHAR(255) Uzu6>yT
SELECT @StartTime = GETDATE(), d$dy6{/YD
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ahBqYAK9
DBCC SHRINKFILE (@LogicalFileName, @NewSize) sibYJK Oy
EXEC (@TruncLog) ]-fkmnmWX
-- Wrap the log if necessary. :GHv3hn5
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m>>.N?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )9QtnM
AND (@OriginalSize * 8 /1024) > @NewSize \;LDE`Q_x
BEGIN -- Outer loop. L4#pMc
SELECT @Counter = 0
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) X#Bb?Pv
BEGIN -- update A4K.,bZ
INSERT DummyTrans VALUES ('Fill Log') {$*N1$(%
DELETE DummyTrans |c_qq Bd
SELECT @Counter = @Counter + 1 jc}G+|`
END !vnQ;g5
EXEC (@TruncLog) vF$i"^;tJ;
END :+rGBkw1m
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 7s9h:/Lu
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _73q,3`24
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,"(L2+Yp
FROM sysfiles 7N.b-}$(
WHERE name = @LogicalFileName >DqF>w.1
DROP TABLE DummyTrans :6^7l/p
SET NOCOUNT OFF sp9gz~Kq
8、说明:更改某个表 J=4>zQLW
exec sp_changeobjectowner 'tablename','dbo' bz>X~
9、存储更改全部表 { _rfhz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $vO&C6m$
@OldOwner as NVARCHAR(128), {K z,_bo
@NewOwner as NVARCHAR(128) 7nZPh3%
AS e#eVc'=cDR
DECLARE @Name as NVARCHAR(128) C0rf
DECLARE @Owner as NVARCHAR(128) !40>LpL[
DECLARE @OwnerName as NVARCHAR(128) !3ggQG!e
DECLARE curObject CURSOR FOR d[ N1zQW
select 'Name' = name,
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'Owner' = user_name(uid) gEA SYIQ
from sysobjects \bA Yic
where user_name(uid)=@OldOwner >@ t
order by name tYS4"Nfb+
OPEN curObject +n3I\7G>
FETCH NEXT FROM curObject INTO @Name, @Owner 2_o#Gx'
WHILE(@@FETCH_STATUS=0) DL]tg[w{
BEGIN pl[J!d.c
if @Owner=@OldOwner "
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begin @NHh-&;w
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <=uYfi 3,
exec sp_changeobjectowner @OwnerName, @NewOwner D28`?B9(
end 8a)AuAi?!
-- select @name,@NewOwner,@OldOwner Ic&h8vSU
FETCH NEXT FROM curObject INTO @Name, @Owner q2GW3t
END D7Q+w
close curObject YFKE>+
deallocate curObject G)3I+uxn
GO }x8!{Y#cF
10、SQL SERVER中直接循环写入数据 1+o]+Jz|
declare @i int 3>,}N9P-v
set @i=1 IRdt:B|@
while @i<30 jvT'N@
begin E+td~&x
insert into test (userid) values(@i) hbjAxioA
set @i=@i+1 *[Hrbln
end #;!&8iH
小记存储过程中经常用到的本周,本月,本年函数 'sNZFB#
Dateadd(wk,datediff(wk,0,getdate()),-1) S63Zk0(25
Dateadd(wk,datediff(wk,0,getdate()),6) )Q)qz$h@
Dateadd(mm,datediff(mm,0,getdate()),0) BFLef3~.0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 8;PkuJR_]
Dateadd(yy,datediff(yy,0,getdate()),0)
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8v:{BHX
上面的SQL代码只是一个时间段 ?RRO
Dateadd(wk,datediff(wk,0,getdate()),-1) 0p.bmQSH
Dateadd(wk,datediff(wk,0,getdate()),6) g(7-3q8eq
就是表示本周时间段. "4j~2{{F
下面的SQL的条件部分,就是查询时间段在本周范围内的: V"FQVtTx7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) lame/B&nc
而在存储过程中 t [QD#;
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ${Z0@G+
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Xtp8^4Va