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。 4HEp}Y"}V
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一、基础 -I4-K%%B`
1、说明:创建数据库 FM:ax{
CREATE DATABASE database-name a}eM ny
2、说明:删除数据库 bv,_7UOG
drop database dbname sI4Ql0[
3、说明:备份sql server i2`i5&*
--- 创建 备份数据的 device v`#T)5gl-
USE master E&r*[;$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' sr,8zKM)
--- 开始 备份 3lYM(DT
BACKUP DATABASE pubs TO testBack fXCx!3m
4、说明:创建新表 #]bWE$sU<
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) P[-2^1P"
根据已有的表创建新表: N4Yvt&
A:create table tab_new like tab_old (使用旧表创建新表) l<0BMw S8
B:create table tab_new as select col1,col2... from tab_old definition only {<%zcNKl^L
5、说明:删除新表 ;B>2oq
drop table tabname #"% ]1={b
6、说明:增加一个列 `~Nd4EA)2
Alter table tabname add column col type H)aeSF5
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。 oW3{&vfz
7、说明:添加主键: Alter table tabname add primary key(col) kr2V
说明:删除主键: Alter table tabname drop primary key(col) NidG|Yg~Z
8、说明:创建索引:create [unique] index idxname on tabname(col....) :{<( )gfk
删除索引:drop index idxname vy\;#X!
注:索引是不可更改的,想更改必须删除重新建。 3l"7 $B
9、说明:创建视图:create view viewname as select statement "QA <5P
删除视图:drop view viewname I;kKY
10、说明:几个简单的基本的sql语句 Cn4o^6? "
选择:select * from table1 where 范围 m5Gt8Z 6a
插入:insert into table1(field1,field2) values(value1,value2) 6(
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删除:delete from table1 where 范围 c`I`@Bed
更新:update table1 set field1=value1 where 范围 H@%Y!z@\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .hW_P62\#
排序:select * from table1 order by field1,field2 [desc] @4dB$QF`&
总数:select count as totalcount from table1 Mo`7YS-Y
求和:select sum(field1) as sumvalue from table1 GGHe{l
平均:select avg(field1) as avgvalue from table1 RGy4p)z*+
最大:select max(field1) as maxvalue from table1 [H$37Hx!
最小:select min(field1) as minvalue from table1 |KFRC)g
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11、说明:几个高级查询运算词 G\3@QgyQ
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A: UNION 运算符 ((L=1]w
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。 xv;'27mUt
B: EXCEPT 运算符 sp*_;h3'
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。 [U[saR\
C: INTERSECT 运算符 . zf#S0y%(
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。 R /J@XP
注:使用运算词的几个查询结果行必须是一致的。 xKIzEN
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12、说明:使用外连接 $rFLhp}
A、left outer join: GQ~wx1jj1
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 KO/Z|I
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1?s]nU
B:right outer join: >-fOkOWXy
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 DEEQ/B{
C:full outer join: pX3Q@3,$
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。 j8kax/*[
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二、提升 I_66q7U"0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) B;.]<k'3
法一:select * into b from a where 1<>1 pj?wQ'
法二:select top 0 * into b from a qzq_3^66
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) (bnyT?p%
insert into b(a, b, c) select d,e,f from b; B[k {u#Kp
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 B7?T5G
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9&e=s<6dO
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !#P|2>>u
4、说明:子查询(表名1:a 表名2:b) ;`<uo$R
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) 3_k.`s_Z
5、说明:显示文章、提交人和最后回复时间 $S{B{FK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'lwLe3.c
6、说明:外连接查询(表名1:a 表名2:b) zFVNb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c L|hsGm\
7、说明:在线视图查询(表名1:a ) =?fxPT[1K
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7,Tg>,%Q
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 <n+?7`d,
select * from table1 where time between time1 and time2 FJ]BB4
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select a,b,c, from table1 where a not between 数值1 and 数值2 oJ}!qrrH
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') !bEy~.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 HmxA2 ~C
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) I75>$"$<
11、说明:四表联查问题: 6
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... r9:Cq
12、说明:日程安排提前五分钟提醒 Ak(_![Q:q\
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 3q7Z?1'o
13、说明:一条sql 语句搞定数据库分页 nff
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 OhUEp g[
14、说明:前10条记录 Jo%5 NXts4
select top 10 * form table1 where 范围 @lvvI<U
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) @wa2Z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Ww8<f$
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 f0UB?
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(select a from tableA ) except (select a from tableB) except (select a from tableC) Y`$dtg {
17、说明:随机取出10条数据 p9c`rl_N
select top 10 * from tablename order by newid() 1CS[%)-c
18、说明:随机选择记录 M[aF3bbN
select newid() <_X`D4g]XO
19、说明:删除重复记录 v/ dyu
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 6:Eu[PE~w
20、说明:列出数据库里所有的表名 Nr24Rv
select name from sysobjects where type='U' 1;O%8sp&
21、说明:列出表里的所有的 \^=Wp'5R
select name from syscolumns where id=object_id('TableName') Ur^~fW1o
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 9ure:Dko(Y
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type VK/@jrL+
显示结果: uL`6}0
type vender pcs ci]IH]x
电脑 A 1 ;%u'w;sgq
电脑 A 1 >cVEr+r9t
光盘 B 2 gWlv;oq
光盘 A 2 "'389*-
手机 B 3 )"Ef* /+
手机 C 3 JY$B%R4;]
23、说明:初始化表table1 1Q$ePo
TRUNCATE TABLE table1 W*D]?hXU;
24、说明:选择从10到15的记录 J$Huzs#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Iud]*5W
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三、技巧 }o>6 y>=
1、1=1,1=2的使用,在SQL语句组合时用的较多 j,7NLb9M
"where 1=1" 是表示选择全部 "where 1=2"全部不选, y,I ?3p|S
如: >FrF"u:kM
if @strWhere !='' gu'Y k
begin >MXE)=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere eh`s fH
end x 6=Yt{
else 'g3!SdaLF
begin jt({@;sU[<
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b{:c0z<
end /jBjqE;_
我们可以直接写成 '%JIc~LJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere axf 4N@
2、收缩数据库 %by8i1HR
--重建索引 L;wfTZa
DBCC REINDEX desrKnY
DBCC INDEXDEFRAG os=Pr{
--收缩数据和日志 *-KgU'u?
DBCC SHRINKDB ~d+.w%Z`
DBCC SHRINKFILE B@R3j
3、压缩数据库 x3X^\Ig
dbcc shrinkdatabase(dbname) iy{n"#uX
4、转移数据库给新用户以已存在用户权限 D%tcYI(
exec sp_change_users_login 'update_one','newname','oldname' $UgQ1Qc
go LyEM^d]
5、检查备份集 jzRfD3_s
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^TC<_]7
6、修复数据库 zli@X Z#
ALTER DATABASE [dvbbs] SET SINGLE_USER -2)6QKh~D
GO `# N j8
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK B hO*Pfs
GO _;o)MTw|'
ALTER DATABASE [dvbbs] SET MULTI_USER *aE/\b
GO dNQR<v\IL
7、日志清除 PEKU
SET NOCOUNT ON _$wXHONt
DECLARE @LogicalFileName sysname, AKKp-I5
@MaxMinutes INT, U"Gg
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@NewSize INT &$\B&Hp@
USE tablename -- 要操作的数据库名 ^/K]id7 2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^A4bsoW
@MaxMinutes = 10, -- Limit on time allowed to wrap log. r2KfZ>tWg"
@NewSize = 1 -- 你想设定的日志文件的大小(M) v#. %eF
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-- Setup / initialize @O&<_&
DECLARE @OriginalSize int +<\)b(
SELECT @OriginalSize = size >8I?YT.
FROM sysfiles
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WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + sj"zgE)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + h KZ<PwBi
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' V^n?0^o
FROM sysfiles 2ZZ%BV!s
WHERE name = @LogicalFileName 4Nz@s^9
CREATE TABLE DummyTrans
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(DummyColumn char (8000) not null) SN${cs%
DECLARE @Counter INT, +#||
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@StartTime DATETIME, Y|*a,H"_
@TruncLog VARCHAR(255) /< OoZf+[
SELECT @StartTime = GETDATE(), 5Op|="W.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' XXx]~m
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ukf4Q\@w
EXEC (@TruncLog) ,KT[ }P7
-- Wrap the log if necessary. .u+ZrA#
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired EWcqMD]4u
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -y@#
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AND (@OriginalSize * 8 /1024) > @NewSize B)q 5m
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BEGIN -- Outer loop. j %3wD2 l
SELECT @Counter = 0 E%B:6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _LVi}mM
BEGIN -- update yvQRr75
INSERT DummyTrans VALUES ('Fill Log') m$ubxI)
DELETE DummyTrans BZ '63
SELECT @Counter = @Counter + 1 m1d*Lt>F@
END |%V-|\GJ~j
EXEC (@TruncLog) iSiez'
END nIckI!U#D
SELECT 'Final Size of ' + db_name() + ' LOG is ' + d*M:PjG@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + vtm?x,h
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' n`W7g@Sg#I
FROM sysfiles (IE\}QcK
WHERE name = @LogicalFileName cft'% IEs
DROP TABLE DummyTrans h$[tEmD%
SET NOCOUNT OFF aMLtZ7i>
8、说明:更改某个表 lRy^Wp
exec sp_changeobjectowner 'tablename','dbo' '}F=U(!
9、存储更改全部表 Hzn6H4Rc
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )2&U
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@OldOwner as NVARCHAR(128), _?aI/D
@NewOwner as NVARCHAR(128) SU8vz/\%y
AS
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DECLARE @Name as NVARCHAR(128) [v,Y-}wQ)
DECLARE @Owner as NVARCHAR(128) 'yIz<o
DECLARE @OwnerName as NVARCHAR(128) a7Xa3 vlpO
DECLARE curObject CURSOR FOR n'i~1pM,?
select 'Name' = name, ?Dr_WFNjO
'Owner' = user_name(uid) cBGR%w\t%
from sysobjects bb@3%r|_<
where user_name(uid)=@OldOwner Ig.9:v`
order by name ;7
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OPEN curObject 3|Vh[iAa\
FETCH NEXT FROM curObject INTO @Name, @Owner +|iJQF
WHILE(@@FETCH_STATUS=0) saPg2N,
BEGIN ~T'!.^/
if @Owner=@OldOwner 8-"lK7
begin ,cF
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~HM,@5dFC
exec sp_changeobjectowner @OwnerName, @NewOwner C7hJE-
end GcHy`bQbiX
-- select @name,@NewOwner,@OldOwner i*3*)l y
FETCH NEXT FROM curObject INTO @Name, @Owner 5Mb5t;4b
END vIK+18v7
close curObject kX1#+X
deallocate curObject Ln3<r&&Jz
GO IXJ6w:E
10、SQL SERVER中直接循环写入数据 iN]#XIQ%
declare @i int {*lRI
set @i=1 3<:m;F*#
while @i<30 >'MT]@vez
begin @ /yQ4Gr
insert into test (userid) values(@i) ]?/7iM
set @i=@i+1 wpW3%r;9
end :Qd{V3*]
小记存储过程中经常用到的本周,本月,本年函数 Q"Ur*/-U
Dateadd(wk,datediff(wk,0,getdate()),-1) | GqKa
Dateadd(wk,datediff(wk,0,getdate()),6) Mu>WS)1lS
Dateadd(mm,datediff(mm,0,getdate()),0) /z(;1$Ld6{
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) zF-M9f$_PY
Dateadd(yy,datediff(yy,0,getdate()),0) ?_<14%r;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) U 5f<4I
上面的SQL代码只是一个时间段 'UN
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Dateadd(wk,datediff(wk,0,getdate()),-1) )V6<'>1WZ
Dateadd(wk,datediff(wk,0,getdate()),6) V+y yy-/
就是表示本周时间段. C EMe2~
下面的SQL的条件部分,就是查询时间段在本周范围内的: rf[w&~R
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) JPt0k
而在存储过程中 {Bd 0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) #sg^l>/*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qE W3k),