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。 O aaH$B
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一、基础 l!@ 1u^v2
1、说明:创建数据库 aq$q
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CREATE DATABASE database-name ,Xtj;@~-
2、说明:删除数据库 KUKI qAA
drop database dbname bo>E"<
3、说明:备份sql server ]r959+\$
--- 创建 备份数据的 device Dr+ Ps
USE master 12OlrU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 30d#Lq
--- 开始 备份 oY.\)eJ~>
BACKUP DATABASE pubs TO testBack iRt*A6`m+
4、说明:创建新表 vaB!R 0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Y0Rg Jn
根据已有的表创建新表: ^Xs]C|=W
A:create table tab_new like tab_old (使用旧表创建新表) q.T:0|
B:create table tab_new as select col1,col2... from tab_old definition only H,K`6HH
5、说明:删除新表 ?1w"IjUS
drop table tabname ag;dc
6、说明:增加一个列 FN\GE\H
Alter table tabname add column col type =:~(m
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。 0Oap39
7、说明:添加主键: Alter table tabname add primary key(col) 6tm\L
说明:删除主键: Alter table tabname drop primary key(col) O{q&]~,
8、说明:创建索引:create [unique] index idxname on tabname(col....) vRr9%zx
删除索引:drop index idxname V3uXan_
注:索引是不可更改的,想更改必须删除重新建。 B^q<2S;
9、说明:创建视图:create view viewname as select statement Z@M6!;y#
删除视图:drop view viewname \fi}Q\|C
10、说明:几个简单的基本的sql语句 <5IQc[3]aP
选择:select * from table1 where 范围 (Ilsk{aB;A
插入:insert into table1(field1,field2) values(value1,value2) 0*yJ %
删除:delete from table1 where 范围 [h-norB((
更新:update table1 set field1=value1 where 范围 "DpKrVuG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Pm?B
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排序:select * from table1 order by field1,field2 [desc] T*+A.G@L"
总数:select count as totalcount from table1 A3q*$.[
求和:select sum(field1) as sumvalue from table1 lT,+bU
平均:select avg(field1) as avgvalue from table1 sE9Ckc5
最大:select max(field1) as maxvalue from table1 1;&T^Gdj
最小:select min(field1) as minvalue from table1 h(N=V|0
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11、说明:几个高级查询运算词 _yVPpA[a
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A: UNION 运算符 i@,]Z~]
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。 I7G,`h+H
B: EXCEPT 运算符 VMHC/jlX@r
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。 =x
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C: INTERSECT 运算符 C*rd;+1A
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。 ug&92Hdvy3
注:使用运算词的几个查询结果行必须是一致的。 o;QZe&
12、说明:使用外连接 #{,h@g}W
A、left outer join: jdlG#j-\
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。 /s`;9)G]9
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 \]8i}E1
B:right outer join: }4h0bI
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。 RGp'b
C:full outer join: qjLo&2)
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。 D]u=PqHk2
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二、提升 h8.FX-0& =
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) q[c Etp28h
法一:select * into b from a where 1<>1 E em
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法二:select top 0 * into b from a E}$V2ha0zu
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) e/94y6*>
insert into b(a, b, c) select d,e,f from b; 61:9(*4~!F
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) v{koKQ'Y()
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,`
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ?Ib}
4、说明:子查询(表名1:a 表名2:b) 2AK}D%jfc
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) 0N5bPb
5、说明:显示文章、提交人和最后回复时间 e1^l.>2d6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \EI#az=I
6、说明:外连接查询(表名1:a 表名2:b) __(V C:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c yVYkuO
7、说明:在线视图查询(表名1:a ) e5OVq
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select * from (SELECT a,b,c FROM a) T where t.a > 1; c F=P!2@
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 8\_*1h40s
select * from table1 where time between time1 and time2 OjATSmZ@@
select a,b,c, from table1 where a not between 数值1 and 数值2 Cuv|6t75'
9、说明:in 的使用方法 'tuBuYD\
select * from table1 where a [not] in ('值1','值2','值4','值6') b1)\Zi
10、说明:两张关联表,删除主表中已经在副表中没有的信息 }`]]b+_b>@
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) K~@`o-Z[
11、说明:四表联查问题: VIg\]%qse
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 ..... 4(|yD;
12、说明:日程安排提前五分钟提醒 s41adw>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `^e*T'UPl
13、说明:一条sql 语句搞定数据库分页 fTgbF{?xh
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 mATH*[Y
14、说明:前10条记录 Tk](eQsy.v
select top 10 * form table1 where 范围 /.@x
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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.) zq=&4afOE
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) z Lw(@&
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 2@*<9-9
(select a from tableA ) except (select a from tableB) except (select a from tableC) # JFYws
17、说明:随机取出10条数据 KBj@V6Q
select top 10 * from tablename order by newid() AysL-sqR
18、说明:随机选择记录 #[(gIOrNn8
select newid() GGM5m|4
19、说明:删除重复记录 X+*<B(E
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %ET
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20、说明:列出数据库里所有的表名 ?RJdn]`4j
select name from sysobjects where type='U' 07Y_^d
21、说明:列出表里的所有的 X TM$a9)
select name from syscolumns where id=object_id('TableName') s9 &)Fv-#V
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 y9ip[Xn-$:
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 =h7[E./U1
显示结果: |?yE^$a
type vender pcs xD^wTtT
电脑 A 1 )@,N7Y1h
电脑 A 1 IywiCMjH
光盘 B 2 V8T#NJ
光盘 A 2 S*s:4uf
手机 B 3 J@gm@ jLc
手机 C 3 K4Y'B
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23、说明:初始化表table1 $E @ouX?
TRUNCATE TABLE table1 RUqO!s~#rY
24、说明:选择从10到15的记录 G g(NGT
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc yZ|+VXO
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三、技巧 z2v<a{e
1、1=1,1=2的使用,在SQL语句组合时用的较多 Q-3r}jJe
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~f .y:Sbb
如: IqXBz.p
if @strWhere !='' Fr2kbQTg;
begin W7$s5G,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere A`IHP{aB
end &M$Bt} <
else Xout:dn
begin \Vz,wy%-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !"`Jqs
end u?H@C)P
我们可以直接写成 C_-%*]*,j
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere drbe#FObX
2、收缩数据库 "A]?M<R
--重建索引 o:H'r7N
DBCC REINDEX 5
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DBCC INDEXDEFRAG ]I8]mUiUH
--收缩数据和日志 hcQSB00D^
DBCC SHRINKDB lS#7xh
DBCC SHRINKFILE X:U=MWc>
3、压缩数据库 u |'8a1
dbcc shrinkdatabase(dbname) k?<i*;7
4、转移数据库给新用户以已存在用户权限 ma1(EJ/
exec sp_change_users_login 'update_one','newname','oldname' eVrnVPkM
go )=y.^@UT@
5、检查备份集 El {r$-}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *q}FV2
6、修复数据库 ,}u,)7
ALTER DATABASE [dvbbs] SET SINGLE_USER i},d[
GO ; 4l-M2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK fjcr<&{:
GO Bpm,mp4g\#
ALTER DATABASE [dvbbs] SET MULTI_USER 0e)lY='^_
GO >CH
7、日志清除 "oHp.$+K
SET NOCOUNT ON xm^N8
DECLARE @LogicalFileName sysname, k]t,q$Vd
@MaxMinutes INT, xna7kA
@NewSize INT 'y< t/qo
USE tablename -- 要操作的数据库名 1>hb-OMX
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 CcBQo8!G
@MaxMinutes = 10, -- Limit on time allowed to wrap log.
ccRlql(
@NewSize = 1 -- 你想设定的日志文件的大小(M) x!OWJ/O
-- Setup / initialize EG%I1F%
DECLARE @OriginalSize int mZ]P[lQ'5
SELECT @OriginalSize = size ?n2C
FROM sysfiles *3!(*F@M,
WHERE name = @LogicalFileName dr.**fGYde
SELECT 'Original Size of ' + db_name() + ' LOG is ' + (Z5qf
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + MST:.x ;
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' HJc<Gwm
FROM sysfiles +I*k0"gj6
WHERE name = @LogicalFileName h]<GTWj
CREATE TABLE DummyTrans _cR6ik zW(
(DummyColumn char (8000) not null) eR7qE) h
DECLARE @Counter INT, ?0 HR(N(z!
@StartTime DATETIME, Pa3{Ds
@TruncLog VARCHAR(255) I+*osk
SELECT @StartTime = GETDATE(), B^H4Q
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' j'\>Nn+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) !&qx7eOSpP
EXEC (@TruncLog) &Q2NU$
-- Wrap the log if necessary. yVT&rQ"{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Um/CR!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 2TE\4j
AND (@OriginalSize * 8 /1024) > @NewSize 8b-7]%
BEGIN -- Outer loop. T:be 9 5!,
SELECT @Counter = 0 x6"/z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1aBD^^Y
BEGIN -- update GVeL~Q
INSERT DummyTrans VALUES ('Fill Log') tX@0:RX%
DELETE DummyTrans ]^Sd9ba
SELECT @Counter = @Counter + 1 th5
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END C_6GOpl
EXEC (@TruncLog) cR,'o'V/
END 65'`uuPx
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8FAT(f//.
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^!q 08`0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' eVJ= .?r
FROM sysfiles NKRaQr
WHERE name = @LogicalFileName c'"#q)
DROP TABLE DummyTrans qsD?dHi7
SET NOCOUNT OFF !>CE(;E>z
8、说明:更改某个表 V+Y|4Y&
exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 >_rzT9gX&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ` 52%XI
@OldOwner as NVARCHAR(128), j kSc&
@NewOwner as NVARCHAR(128) kTr6{9L
AS -0{T
DECLARE @Name as NVARCHAR(128) d1UVvyH
DECLARE @Owner as NVARCHAR(128) P
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DECLARE @OwnerName as NVARCHAR(128) oxUE79
DECLARE curObject CURSOR FOR &r&;<Q
select 'Name' = name, V*~1,6N[
'Owner' = user_name(uid) ,h3269$J
from sysobjects J@oEV=L
where user_name(uid)=@OldOwner jVLY!7Z4
order by name ='7er.~\
OPEN curObject K#_~
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FETCH NEXT FROM curObject INTO @Name, @Owner :&xz5c`"04
WHILE(@@FETCH_STATUS=0) 83mlZ1jQz
BEGIN ev~dsk6k
if @Owner=@OldOwner
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begin $Sp*)A]E`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) I8%d;G~
exec sp_changeobjectowner @OwnerName, @NewOwner N!tpzHXw
end h`z2!F4
-- select @name,@NewOwner,@OldOwner @WhZx*1
FETCH NEXT FROM curObject INTO @Name, @Owner *jYHd#UZx4
END |^YzFrc
close curObject &?P=arU
deallocate curObject .}IK}A/-
GO >+yqjXRzm
10、SQL SERVER中直接循环写入数据 F% F
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declare @i int lt@
set @i=1 K<$wz/\
while @i<30 It#h p,@e
begin !F=|*j
insert into test (userid) values(@i) `'z(--J}`
set @i=@i+1 \hjk$Gq
end s-QM6*
小记存储过程中经常用到的本周,本月,本年函数 >t1_5
Dateadd(wk,datediff(wk,0,getdate()),-1) QH@Q\
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Dateadd(wk,datediff(wk,0,getdate()),6) fG:PdIJ7_
Dateadd(mm,datediff(mm,0,getdate()),0) Xz;et>UD*B
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) .OVW4svX
Dateadd(yy,datediff(yy,0,getdate()),0) <dju6k7uz
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 08<k'Oi]
上面的SQL代码只是一个时间段 F{#N6,T
Dateadd(wk,datediff(wk,0,getdate()),-1) !yoSMI-
Dateadd(wk,datediff(wk,0,getdate()),6) +?[,{WtV
就是表示本周时间段. [mJmT->
下面的SQL的条件部分,就是查询时间段在本周范围内的: Mpu8/i
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8dYPn+`
而在存储过程中 (M,IgSn9
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 5y%-K=d
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $bd2TVNV: