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。 jbqhNsTNK
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一、基础 \8!&XcA
1、说明:创建数据库 hsQrHs'k
CREATE DATABASE database-name m
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2、说明:删除数据库 }>:x
drop database dbname 1&
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3、说明:备份sql server 6#k
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--- 创建 备份数据的 device imtW[ y+4
USE master %Iv0<oU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' GGs3r;(t
--- 开始 备份 &0
VM <
BACKUP DATABASE pubs TO testBack K`@GNT&
4、说明:创建新表 F~ n}Ep~1
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Iy](?b
根据已有的表创建新表: d+|8({X]D8
A:create table tab_new like tab_old (使用旧表创建新表) ]*^mT&$7
B:create table tab_new as select col1,col2... from tab_old definition only gTR:9E:B
5、说明:删除新表 U"xI1fg%b
drop table tabname (0qdU;
6、说明:增加一个列 c(bh i
Alter table tabname add column col type kvdzD6T
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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。 x]k^JPX
7、说明:添加主键: Alter table tabname add primary key(col) EYUr.#:
说明:删除主键: Alter table tabname drop primary key(col) zu}h3n5
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3yXF|
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删除索引:drop index idxname sf?D4UdIH
注:索引是不可更改的,想更改必须删除重新建。 Lvc*L6
9、说明:创建视图:create view viewname as select statement }d)>pH
删除视图:drop view viewname ;sa-Bh=j^
10、说明:几个简单的基本的sql语句 11
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选择:select * from table1 where 范围 fZXJPy;n
插入:insert into table1(field1,field2) values(value1,value2) =5LtEgHU
删除:delete from table1 where 范围 >U9!KB
更新:update table1 set field1=value1 where 范围 $<]y.nr|CX
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! lE[LdmwDrb
排序:select * from table1 order by field1,field2 [desc] >.#uoW4ZV
总数:select count as totalcount from table1 JPiC/
求和:select sum(field1) as sumvalue from table1 k-T_,1l{
平均:select avg(field1) as avgvalue from table1 \nx^=4*yk
最大:select max(field1) as maxvalue from table1 Xt8;Pl
最小:select min(field1) as minvalue from table1 C
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11、说明:几个高级查询运算词 ,_Fq*6
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A: UNION 运算符 .dp~%!"Sn,
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 x-Z`^O
B: EXCEPT 运算符 :%A1k2
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 C|W_j&S65
C: INTERSECT 运算符 @^;WC+\0
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 %I%F
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注:使用运算词的几个查询结果行必须是一致的。 ZH`6>:
12、说明:使用外连接 TRAs5I%
A、left outer join: Os8]iNvW\
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 8R:H{)o~s}
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c r#]gAG4t\
B:right outer join: uHQJ&
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 w]) bQ7)
C:full outer join: gA!-F}x$
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。 &6MGPh7T
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二、提升 n`6 8<ybl5
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) akBR"y:~:H
法一:select * into b from a where 1<>1 rEdr8qw
法二:select top 0 * into b from a Cz?N[dhh
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *u7C){)gr[
insert into b(a, b, c) select d,e,f from b; p0$K.f|
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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) B{/Pv0y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \9i.dF
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. klUxt?-
4、说明:子查询(表名1:a 表名2:b) !U,qr0h
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) 0tn5>Dsk
5、说明:显示文章、提交人和最后回复时间 n4k.tq
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8o4<F%ot
6、说明:外连接查询(表名1:a 表名2:b) .K}u`v T
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R.|fc5_"+
7、说明:在线视图查询(表名1:a ) g;v{JB
select * from (SELECT a,b,c FROM a) T where t.a > 1; zG@9-s* L
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 F>n<;<
select * from table1 where time between time1 and time2 ,Xk8{=
select a,b,c, from table1 where a not between 数值1 and 数值2 xHykU;p@
9、说明:in 的使用方法 .m/Lon E
select * from table1 where a [not] in ('值1','值2','值4','值6') ILF"m;
10、说明:两张关联表,删除主表中已经在副表中没有的信息 MJV&%E6{:{
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7x-k-F3
11、说明:四表联查问题: c2?(.UV
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 ..... 52l|
12、说明:日程安排提前五分钟提醒 MY9?957F
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^lRXc.c z
13、说明:一条sql 语句搞定数据库分页 x}N+vK
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 fPK|Nw]b
14、说明:前10条记录 ]v94U b
select top 10 * form table1 where 范围 ID'@}69.S
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.) !&E>8h
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w6R=r
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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 DWk'6;e4j
(select a from tableA ) except (select a from tableB) except (select a from tableC) $./JA)`
17、说明:随机取出10条数据 )J~Qx-jG
select top 10 * from tablename order by newid() I^M3>}p
18、说明:随机选择记录 vCbqZdy?
select newid() 4p>@UB&U
19、说明:删除重复记录 =#T6,[5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5[X^1
20、说明:列出数据库里所有的表名 ;5" r)F+P
select name from sysobjects where type='U' *M+:GH/5
21、说明:列出表里的所有的 8xg:ItJaA0
select name from syscolumns where id=object_id('TableName') )5d&K8@
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Sqc*u&W
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Kj}hb)HU
显示结果: (sJ{27b_
type vender pcs m++VW0Y>
电脑 A 1 1x M&"p:
电脑 A 1 >\}2("bv
光盘 B 2 V}pw ,2s
光盘 A 2 k@4]s_2
手机 B 3 ]4uIb+(S
手机 C 3 rI;e!EW
23、说明:初始化表table1 vh?({A#>.E
TRUNCATE TABLE table1 }6C&N8f
24、说明:选择从10到15的记录 dW8'$!@!!
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc .__X[Mzth3
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三、技巧 A{5k}
1、1=1,1=2的使用,在SQL语句组合时用的较多 Ha)w*1&w"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |;rjr_I
如: /kx:BoV
if @strWhere !='' i7e{REBXb
begin <T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -U%wLkf|
end G:u[Lk#6K
else /d'^XYOC
begin \e'>$8%T
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' SAThY$)6
end f} }Bb8
我们可以直接写成 "St, 4b
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v[m/>l2[P
2、收缩数据库 ZwO&G\A^
--重建索引 Lk#u^|Eq7=
DBCC REINDEX Xb$)}n\9
DBCC INDEXDEFRAG ~+3f8%
--收缩数据和日志 ':o.vQdJ
DBCC SHRINKDB #0G9{./C
DBCC SHRINKFILE KMoRMCT
3、压缩数据库 tEiN(KA!5
dbcc shrinkdatabase(dbname) Q(Vc/
4、转移数据库给新用户以已存在用户权限 t4h05 i
exec sp_change_users_login 'update_one','newname','oldname' M9bb,`X>Q
go b LL!iz?
5、检查备份集 {*jkx,|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Qkr'C
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6、修复数据库 z ;
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ALTER DATABASE [dvbbs] SET SINGLE_USER 7zR7v
GO z<^HohT
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK tBrd+}e2*
GO js8uvZ i
ALTER DATABASE [dvbbs] SET MULTI_USER VD36ce9
GO _e ~EQ[,
7、日志清除 <0R?#^XBZB
SET NOCOUNT ON 'f;+*~*L
DECLARE @LogicalFileName sysname, wF@qBDxg
@MaxMinutes INT, x0Tb7y`
@NewSize INT iKp4@6an
USE tablename -- 要操作的数据库名 Pb]s+1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ;K$E;ZhPN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <-}6X
@NewSize = 1 -- 你想设定的日志文件的大小(M) wQM(Lm#Q
-- Setup / initialize C+y:<oo)
DECLARE @OriginalSize int YroKC+4"i
SELECT @OriginalSize = size "5Kx]y8
FROM sysfiles %I6iXq#
WHERE name = @LogicalFileName )vuxy
SELECT 'Original Size of ' + db_name() + ' LOG is ' + TO( =4;U
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + &h4(lM
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' :kY][_
FROM sysfiles )
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WHERE name = @LogicalFileName |!57Z4X
CREATE TABLE DummyTrans lpSM p
(DummyColumn char (8000) not null) oxcAKo
DECLARE @Counter INT, +Icg;m{
@StartTime DATETIME, ^BNg^V.
@TruncLog VARCHAR(255) L2Gm0 v
SELECT @StartTime = GETDATE(), @#8F5G#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3b#KrN'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LAMTf"a
EXEC (@TruncLog) g&BF#)7C
-- Wrap the log if necessary. (U$ F) 7
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired = UTv
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p_P'2mf
AND (@OriginalSize * 8 /1024) > @NewSize m:p1O3[R
BEGIN -- Outer loop. Qs;bVlp!H
SELECT @Counter = 0 !Otyu6&
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 17<\Q(YQ=
BEGIN -- update }4eSB
INSERT DummyTrans VALUES ('Fill Log') U&`M G1uHe
DELETE DummyTrans lg1?g)lv
SELECT @Counter = @Counter + 1 <k<
END v
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EXEC (@TruncLog) uiDR}
END 47
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]<z>YyBA
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + c1MALgK~}\
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 61!R-
FROM sysfiles 0%'&s)#
WHERE name = @LogicalFileName ^(UL$cQ>
DROP TABLE DummyTrans 'H*S-d6V
SET NOCOUNT OFF -] J V
8、说明:更改某个表 3(AgUq
exec sp_changeobjectowner 'tablename','dbo' bX5>qqB]
9、存储更改全部表 Q !S"=2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )ALf!E%{
@OldOwner as NVARCHAR(128), \'E%ue_<9
@NewOwner as NVARCHAR(128) /0"Y.
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AS /o8h1L=
DECLARE @Name as NVARCHAR(128) #p=/P{*
DECLARE @Owner as NVARCHAR(128) %Vive2j C
DECLARE @OwnerName as NVARCHAR(128) lm]4zs /A
DECLARE curObject CURSOR FOR MK~viSgi
select 'Name' = name, /p X\)wi
'Owner' = user_name(uid) e:!&y\'"9
from sysobjects \7gLk:
where user_name(uid)=@OldOwner Et`z7Q*e
order by name bnUd !/;
OPEN curObject v0=^Hym
FETCH NEXT FROM curObject INTO @Name, @Owner *PZN Z{|m
WHILE(@@FETCH_STATUS=0) ^U:pv0Qz
BEGIN ur*1I/v
if @Owner=@OldOwner jk 9K>4W
begin R2t5T-8`c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) rf]]I#C7
exec sp_changeobjectowner @OwnerName, @NewOwner oD~VK,.
end z#bOFVg#
-- select @name,@NewOwner,@OldOwner ho fZpM
FETCH NEXT FROM curObject INTO @Name, @Owner 9:YiLoz?
END mpXco *!_
close curObject Ay2Vz>{
deallocate curObject oDM}h
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GO <P}{0Y~@*W
10、SQL SERVER中直接循环写入数据 >RF[0s'-
declare @i int b/5;377_
set @i=1 /-G;#Wm
while @i<30 ~G5)ya-
begin k gWF@"_
insert into test (userid) values(@i) ;f0+'W
set @i=@i+1 Wx;9N
end >8>`-
小记存储过程中经常用到的本周,本月,本年函数 +a"Asvw2
Dateadd(wk,datediff(wk,0,getdate()),-1) >!`T=(u!
Dateadd(wk,datediff(wk,0,getdate()),6) /g@.1z1w
Dateadd(mm,datediff(mm,0,getdate()),0) ,C(")?4aJ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &``;1/J*W
Dateadd(yy,datediff(yy,0,getdate()),0) uK}k]x\z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) duT2:~H2
上面的SQL代码只是一个时间段 ihf5`mk/$
Dateadd(wk,datediff(wk,0,getdate()),-1) 3vNo D
Dateadd(wk,datediff(wk,0,getdate()),6) l"b78n
就是表示本周时间段. gWgYZX
下面的SQL的条件部分,就是查询时间段在本周范围内的: Q[`_Y3@j
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) QfT&y &
而在存储过程中 YG"P:d;s
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) &xrm;pO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) "fr B5[