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。 U4NH9-U'
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一、基础 |ju+{+
1、说明:创建数据库 <Uy $b4h
CREATE DATABASE database-name M%YxhuT0
2、说明:删除数据库 eiQ42x@Z
drop database dbname n-u
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3、说明:备份sql server $ ~%w21?&
--- 创建 备份数据的 device '2Lx>nByk
USE master xOx=Z\ c
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' /Un\P
--- 开始 备份 t3b M4+n
BACKUP DATABASE pubs TO testBack t52KF#+>
4、说明:创建新表 `x`zv1U
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) .lAPlJOO
根据已有的表创建新表: 6j Rewj
A:create table tab_new like tab_old (使用旧表创建新表) I|l5e2j
B:create table tab_new as select col1,col2... from tab_old definition only C]Q`!e
5、说明:删除新表 t$&'mJ_-w
drop table tabname zZW5M^z8
6、说明:增加一个列 0g2rajS
Alter table tabname add column col type Pm]lr|Q{I
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 &
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7、说明:添加主键: Alter table tabname add primary key(col) u2S8DuJ
说明:删除主键: Alter table tabname drop primary key(col) 3Rhoul[S
8、说明:创建索引:create [unique] index idxname on tabname(col....) +NJIi@
删除索引:drop index idxname [Z2{S-)UM
注:索引是不可更改的,想更改必须删除重新建。 mM r$~^P:
9、说明:创建视图:create view viewname as select statement 8,IQ6Or|-2
删除视图:drop view viewname ]XASim:A
10、说明:几个简单的基本的sql语句 qe5;Pq !G
选择:select * from table1 where 范围 _^g4/G#13c
插入:insert into table1(field1,field2) values(value1,value2) cw,|,uXq
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删除:delete from table1 where 范围 ]K'OH&
更新:update table1 set field1=value1 where 范围 bcUSjG>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! o:B?hr'\
排序:select * from table1 order by field1,field2 [desc] &]tm'N25
总数:select count as totalcount from table1 3+\Zom4
求和:select sum(field1) as sumvalue from table1 r PTfwhs
平均:select avg(field1) as avgvalue from table1 $Xh5N3
最大:select max(field1) as maxvalue from table1 0 ;].q*|#
最小:select min(field1) as minvalue from table1 <MKXFV
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11、说明:几个高级查询运算词 QUm[7<"
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A: UNION 运算符 +k
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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。 P:WxhO/
B: EXCEPT 运算符 9 ^8_^F
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[';B)a
C: INTERSECT 运算符 ,vo]WIQ\:
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。 bk1.H@8
注:使用运算词的几个查询结果行必须是一致的。 yFn~rv|&G
12、说明:使用外连接 ILx4[m7
A、left outer join: )%b 5uZ
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。 Vry*=X&Q
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 2r!- zEV
B:right outer join: (+6N)9rj`/
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。 #Cx#U"~G`
C:full outer join: Z^BZH/I?
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。 PC\p>6xT
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二、提升 liqVfB%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PI@?I&Bo
法一:select * into b from a where 1<>1 A<^X P-Nrp
法二:select top 0 * into b from a (! 8y~n1
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) cE>m/^SKr
insert into b(a, b, c) select d,e,f from b; AiL80W^=d)
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) iJeodfC
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 s)?GscPG!
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. /6F\]JwU
4、说明:子查询(表名1:a 表名2:b) 7[mP@ {
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) /bn$@Cy@
5、说明:显示文章、提交人和最后回复时间 ^G 'n
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b *8+HQ[[#
6、说明:外连接查询(表名1:a 表名2:b) "bB0$>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 %QQ 2u$
7、说明:在线视图查询(表名1:a ) >4q6
select * from (SELECT a,b,c FROM a) T where t.a > 1; `EfFyhG$
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 u9(42jj[$U
select * from table1 where time between time1 and time2 $=X>5B
select a,b,c, from table1 where a not between 数值1 and 数值2 0>46ZzxUZ
9、说明:in 的使用方法 `\P1Ff@z0
select * from table1 where a [not] in ('值1','值2','值4','值6') bPif"dhHe
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?D,j!Hy
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) aI=Q_}8-
11、说明:四表联查问题: NcHU)
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ao0^;
12、说明:日程安排提前五分钟提醒 K-"`A.:S
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;at1|E*
13、说明:一条sql 语句搞定数据库分页 obN8+ j
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Wsp c;]&
14、说明:前10条记录 ;" D~F
select top 10 * form table1 where 范围 +6}CNC9Mp
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) >|`1aCg,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :P
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 H}lz_#Z
(select a from tableA ) except (select a from tableB) except (select a from tableC) Tm9sQ7Oj(
17、说明:随机取出10条数据 ?`xm_udc
select top 10 * from tablename order by newid() zk!7TUZ">w
18、说明:随机选择记录 EiaP1o
select newid() ;y{(#X#
19、说明:删除重复记录 BP l% SL
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "LH!Trl@k
20、说明:列出数据库里所有的表名 %pH|2VB#
select name from sysobjects where type='U' O,-NzGs
21、说明:列出表里的所有的 H+5+;`;
select name from syscolumns where id=object_id('TableName') Q1{9>NI
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 FA\U4l-
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type _>aP5g?Ep
显示结果: 4;>HBCM4-
type vender pcs oX*;iS X
电脑 A 1 uJlW$Oc:.
电脑 A 1 yyk@f%
光盘 B 2 T@`Al('
光盘 A 2 X&| R\v=}
手机 B 3 c10$5V&@
手机 C 3 717G
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23、说明:初始化表table1 bo@
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TRUNCATE TABLE table1 Jh<s '&FR
24、说明:选择从10到15的记录 )m[<lJbw
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc QoZZXCU
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三、技巧 !! )W`
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]T&d_~l
"where 1=1" 是表示选择全部 "where 1=2"全部不选, R/Z7}Q W
如: #6~Bg)7AM
if @strWhere !='' =9`UcTSi6p
begin a1Q%Gn@R
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sekei6#fi
end .)Pul|)d
else [Y?Y@x"MZ
begin QSn18V>{
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' B[6k
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end @HSK[[?
我们可以直接写成 {]Cn@.TPD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Vp0_R9oQ
2、收缩数据库 #U7pT!Fx
--重建索引 ^nNpT!o
DBCC REINDEX I.(@#v7T
DBCC INDEXDEFRAG `m8WLj
--收缩数据和日志 Pa+_{9
DBCC SHRINKDB `u
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DBCC SHRINKFILE `u7^r^>A
3、压缩数据库 RHpjJZUV
dbcc shrinkdatabase(dbname) $uJc/
4、转移数据库给新用户以已存在用户权限 $duT'G, -
exec sp_change_users_login 'update_one','newname','oldname' =yM%#{t&W
go g oyQ',+
5、检查备份集 S("dU`T?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Bd)Cijr
6、修复数据库 [}GK rI
ALTER DATABASE [dvbbs] SET SINGLE_USER :<k
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GO nHH
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9$U4x|n
GO ggitUQ+t;G
ALTER DATABASE [dvbbs] SET MULTI_USER Y)$%-'=b+
GO Q$ Dx:
7、日志清除 2"6qg>]-t
SET NOCOUNT ON ^W9O_5\g4a
DECLARE @LogicalFileName sysname, _Gaem"k|
@MaxMinutes INT, arRU` 6?
@NewSize INT >;bym)
USE tablename -- 要操作的数据库名 _Y/*e<bU
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 HZ}Igw.Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =J]EVD
@NewSize = 1 -- 你想设定的日志文件的大小(M) A+frKoi
-- Setup / initialize ZZHzC+O#^
DECLARE @OriginalSize int Iz'Et'w8!
SELECT @OriginalSize = size z}.6yHS
FROM sysfiles Rm79mh9
WHERE name = @LogicalFileName -Ah&|!/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2eeFaFif
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + O^ui+44wp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Xdl
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FROM sysfiles 6>;OVX
WHERE name = @LogicalFileName ;hV|W{=w
CREATE TABLE DummyTrans MEJX5qG6m
(DummyColumn char (8000) not null) Lccy~2v>
DECLARE @Counter INT, *RVCz|0%w
@StartTime DATETIME, MP<]-M'|<
@TruncLog VARCHAR(255) W[qy4\.B
SELECT @StartTime = GETDATE(), rFkZ'rp74b
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $pAVTz
DBCC SHRINKFILE (@LogicalFileName, @NewSize) L6i|5 P
EXEC (@TruncLog) k~K;r8D/
-- Wrap the log if necessary. `Mbs6AJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ($/l_F
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) sQ^t8Y9
AND (@OriginalSize * 8 /1024) > @NewSize XEagN:
BEGIN -- Outer loop. x-ue1
SELECT @Counter = 0 =Ry8E2NuM
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -K(d]-yv
BEGIN -- update -$:*!55:j
INSERT DummyTrans VALUES ('Fill Log') ;Ss!OFK
DELETE DummyTrans /\uopa
SELECT @Counter = @Counter + 1 {X{S[(|
END m&DI2he
EXEC (@TruncLog) @9n|5.i
END YcclO
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 0'.z|Jg=
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + XzX2V">(%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' iWC}\&i
FROM sysfiles X am8h
WHERE name = @LogicalFileName |e+3d3T35
DROP TABLE DummyTrans s3nt2$=:t
SET NOCOUNT OFF 0vX6n6G}
8、说明:更改某个表 c}|.U
exec sp_changeobjectowner 'tablename','dbo' z~tdLtcX
9、存储更改全部表 Lk@+iHf
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch frW\!r{LT
@OldOwner as NVARCHAR(128), ts@Z5Yw*!
@NewOwner as NVARCHAR(128) 83
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AS ZWGX*F#}P
DECLARE @Name as NVARCHAR(128) (VI(Nv:o@
DECLARE @Owner as NVARCHAR(128) k\;D;e{
DECLARE @OwnerName as NVARCHAR(128) wbcip8<t
DECLARE curObject CURSOR FOR n'{jc6&|
select 'Name' = name, Mp!1xx
'Owner' = user_name(uid) aXQAm$/
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from sysobjects Q&w_kz.
where user_name(uid)=@OldOwner &~/g[\Y
order by name 2RF3pIFrm
OPEN curObject LklE,W
FETCH NEXT FROM curObject INTO @Name, @Owner ]v),[]Xs
WHILE(@@FETCH_STATUS=0) W2h4ej\s
BEGIN m9MYd
if @Owner=@OldOwner \9tJ/~
begin =T26vu
set @OwnerName = @OldOwner + '.' + rtrim(@Name) WQ.{Ag?1
exec sp_changeobjectowner @OwnerName, @NewOwner t?)]xS)
end %mU$]^Tw(
-- select @name,@NewOwner,@OldOwner 1@ &J"*
FETCH NEXT FROM curObject INTO @Name, @Owner dmv0hof
END =54D#,[B
close curObject hCF_pt+
deallocate curObject AB,(%JT/2{
GO s-'~t#h
10、SQL SERVER中直接循环写入数据 dhxzW@'nIL
declare @i int }~PG]A
set @i=1 ,Nhv#U<$
while @i<30 E3[9!L8gb
begin &\~*%:C
insert into test (userid) values(@i) ?u:mscb
set @i=@i+1 HWB\}jcA6u
end )4s7,R
小记存储过程中经常用到的本周,本月,本年函数 !v=/f_6
Dateadd(wk,datediff(wk,0,getdate()),-1) @&&}J
Dateadd(wk,datediff(wk,0,getdate()),6) !\d~9H%`B
Dateadd(mm,datediff(mm,0,getdate()),0) ^>!&]@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @M-Q|
Dateadd(yy,datediff(yy,0,getdate()),0) RrCG(Bh
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) IBeorDIZ
上面的SQL代码只是一个时间段 YcwDNsk
Dateadd(wk,datediff(wk,0,getdate()),-1) I3r")}P
Dateadd(wk,datediff(wk,0,getdate()),6) q UmSB"#Z
就是表示本周时间段. k:j_:C&.
下面的SQL的条件部分,就是查询时间段在本周范围内的: &[j9Up'
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ')yYpWO
而在存储过程中 xr@;w8X`^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V_m!<sr (
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 60nP'xfR