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{a5|<E
G>{;@u
/$x6//0If
一、基础 T[eTT]Z{Ia
1、说明:创建数据库 TM':G9n
CREATE DATABASE database-name ]Ikj Z=
2、说明:删除数据库 !NYc!gYD
drop database dbname *$_<|
g)9
3、说明:备份sql server VG\ER}s&P
--- 创建 备份数据的 device 6i\b&
USE master Da8qR+*x
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R16"lG
--- 开始 备份 T ,gMc
BACKUP DATABASE pubs TO testBack ]?Ru~N}
4、说明:创建新表 bLoYg^T/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sM~|}|p
根据已有的表创建新表: FUm-Fp
A:create table tab_new like tab_old (使用旧表创建新表) )f'cy@b
B:create table tab_new as select col1,col2... from tab_old definition only i@_|18F]`
5、说明:删除新表 M ~!*PCd5
drop table tabname (F7!&] 8%
6、说明:增加一个列 I\DT(9
'E
Alter table tabname add column col type rYq8OZLi
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。 4Kt?; y
;
7、说明:添加主键: Alter table tabname add primary key(col) '89D62\89
说明:删除主键: Alter table tabname drop primary key(col) Hj;j\R >2
8、说明:创建索引:create [unique] index idxname on tabname(col....) w>rglm&
删除索引:drop index idxname f.'o4HSj
注:索引是不可更改的,想更改必须删除重新建。 ./ib{ @A.
9、说明:创建视图:create view viewname as select statement ^QV;[ha,o
删除视图:drop view viewname `pN]Ykt
10、说明:几个简单的基本的sql语句 W~Mj6c~S"
选择:select * from table1 where 范围 K)0 6][,
插入:insert into table1(field1,field2) values(value1,value2) jvm
"7)h
删除:delete from table1 where 范围 ipKkz
更新:update table1 set field1=value1 where 范围 -i @!{ ?
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! W?R$+~G
排序:select * from table1 order by field1,field2 [desc] F1|4([-<]
总数:select count as totalcount from table1 P[ KJuc
求和:select sum(field1) as sumvalue from table1 8N8B${X
平均:select avg(field1) as avgvalue from table1 }
ho8d+A
最大:select max(field1) as maxvalue from table1 z/rN+ ,
最小:select min(field1) as minvalue from table1 #!y|cP~;I
P67r+P,
m&|?mTo>m
Q.6pmaXrb
11、说明:几个高级查询运算词 Ctt{j'-[
1p9f& w
'(u [
A: UNION 运算符 Mk[_yqoCO
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。 #\4uu
B: EXCEPT 运算符 NP^kbF
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_
C: INTERSECT 运算符
[?Aq#av
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。 ~Cj+6CrT
注:使用运算词的几个查询结果行必须是一致的。 #.tF&$ik
12、说明:使用外连接 '1r:z, o|
A、left outer join: xb_35'$M
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。 K$'
J:{yY
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^O[qCX
B:right outer join: <h7C_^L10\
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 l=
!KZaH
C:full outer join: vM\8>p*U
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 HPwmi[
8u;l<^<
bUz7!M$
二、提升 ~`mOs1 d
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) R4QXX7h!
法一:select * into b from a where 1<>1 }[l`R{d5q>
法二:select top 0 * into b from a xp>ra2A
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) tM]qR+
insert into b(a, b, c) select d,e,f from b; jr@<-.
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) 6]Ppa ~Xwq
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 tq>QZEg
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. eyl+D sK
4、说明:子查询(表名1:a 表名2:b) ga~rllm;i
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) 0V`0=" rQ
5、说明:显示文章、提交人和最后回复时间 't^OIil
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b A@du*5>(
6、说明:外连接查询(表名1:a 表名2:b) 3Xf}vdgdM$
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (D{9~^EO>a
7、说明:在线视图查询(表名1:a ) yHk/8
select * from (SELECT a,b,c FROM a) T where t.a > 1; )0RH"#,2L
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 x8gUP
select * from table1 where time between time1 and time2 ,uEWnZ"4
select a,b,c, from table1 where a not between 数值1 and 数值2 ] X4A)%i
9、说明:in 的使用方法 oe4Fy}Y_;
select * from table1 where a [not] in ('值1','值2','值4','值6') UG48g}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L&'2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) CQzJ_aSJ(
11、说明:四表联查问题: sRb)*p'
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 ..... (K>5DU
12、说明:日程安排提前五分钟提醒 G4MNcy
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 PS!f&IY}[.
13、说明:一条sql 语句搞定数据库分页 %,-vmqr
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 0j4bu}@
14、说明:前10条记录 -5d8j<,
select top 10 * form table1 where 范围 d^WVWk K
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.) zn>*^h0B
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Ry[VEn>C1
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 x@Z?DS$)
(select a from tableA ) except (select a from tableB) except (select a from tableC) =f{V<i~q
17、说明:随机取出10条数据 f(7/
select top 10 * from tablename order by newid() !}Cd_tj6
18、说明:随机选择记录 oC.:mI
select newid() ~0t]`<y=
19、说明:删除重复记录 tX&Dum $
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) GZ
UDI#
20、说明:列出数据库里所有的表名 +;pdG[N
select name from sysobjects where type='U' [|xHXcW
21、说明:列出表里的所有的 x:"_B
select name from syscolumns where id=object_id('TableName') :kflq
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。 VGA?B@
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 q9yY%
显示结果: ^cDHyB=v4d
type vender pcs .0cm
mpUNq
电脑 A 1 wp-*S}TT
电脑 A 1 -GDX#A-J
光盘 B 2 X]tjT
光盘 A 2 _)zSjFX9
手机 B 3 HpuHJ#l
手机 C 3 mn?<
Zz
23、说明:初始化表table1 M8:gHjwsx
TRUNCATE TABLE table1 5A Vo#}&\
24、说明:选择从10到15的记录 ^zO%O653
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Pfe&wA't
NHPpHY3^.
[^P25K
g
O,X
三、技巧 DU4NPys]y
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,57g_z]V
"where 1=1" 是表示选择全部 "where 1=2"全部不选, D#1'#di*t
如: <<@$0RW
if @strWhere !='' 8@|+-)t
begin [&j!g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere j#9p0[
end ShxB!/s
else t+W+f
begin &M*&oi (
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `<8~tS/. w
end QROe+:
我们可以直接写成 qeb:n$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere E@7";&\-8
2、收缩数据库 oXK`=.\
--重建索引 b`PAOQ
DBCC REINDEX Gnr]qxL
DBCC INDEXDEFRAG `BmAu[(e&
--收缩数据和日志 ~}i&gd|(
DBCC SHRINKDB \@8$tQCZ
DBCC SHRINKFILE 2N9
BI-a
3、压缩数据库 \3hhM}6)DM
dbcc shrinkdatabase(dbname) [58xT>5`m
4、转移数据库给新用户以已存在用户权限 %XMrSlSOp
exec sp_change_users_login 'update_one','newname','oldname' `
Cdk
b5
go CY?]o4IV
5、检查备份集 c1'OIK C
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' h3h2 KqM'
6、修复数据库 Ma0_!|i
ALTER DATABASE [dvbbs] SET SINGLE_USER 'bN\bbR
GO l=`)yc.
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;l[/<J
GO K@Twiw~rB
ALTER DATABASE [dvbbs] SET MULTI_USER `f}}z5
GO cH.T6u_%
7、日志清除 |g}!
F-
SET NOCOUNT ON r3mB"("Z'
DECLARE @LogicalFileName sysname, tV9BVsN
@MaxMinutes INT, $Ud-aRlD
@NewSize INT @ZK#Y){
USE tablename -- 要操作的数据库名 $M@SZknm
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 p)(mF"\8=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. .[? E1we
@NewSize = 1 -- 你想设定的日志文件的大小(M) FZ6.<wN
-- Setup / initialize :=UiEDN@
DECLARE @OriginalSize int Psp3~Kg
SELECT @OriginalSize = size )**k3u
t4
FROM sysfiles !Ui3}
WHERE name = @LogicalFileName _Z~wpO}/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;<1O86!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R|Z $aHQ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' E<1^i;F
FROM sysfiles !:,d^L!bh
WHERE name = @LogicalFileName kZs
CREATE TABLE DummyTrans ?>N82#9Q
(DummyColumn char (8000) not null) ?"$W=*P\o
DECLARE @Counter INT, 4d)w2t?H%
@StartTime DATETIME, ;``*]tY$
@TruncLog VARCHAR(255) y/K% F,WMf
SELECT @StartTime = GETDATE(), @]1E~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' xAMj 16ZF
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Oj:O-PtN2
EXEC (@TruncLog) HU-4k/I~
-- Wrap the log if necessary. ;_R;P;<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired jJg9M'@2!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) sZ{Kl\1@
AND (@OriginalSize * 8 /1024) > @NewSize 0NK]u~T<
BEGIN -- Outer loop. g+hz>^Wg
SELECT @Counter = 0 pM9Hav@iWU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) mDC{c ?
BEGIN -- update
w1F7gd
INSERT DummyTrans VALUES ('Fill Log') :W<aga;J
DELETE DummyTrans $g$~TuA
w
SELECT @Counter = @Counter + 1 [CGvM{
END j01.`G7Q
EXEC (@TruncLog) ,-ZAI b*
END Xw!eB?A
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8RbtI4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + g><u(3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !!E_WDZ#9
FROM sysfiles [-bL>8
WHERE name = @LogicalFileName c5>&~^~>Tx
DROP TABLE DummyTrans #.?DsK_:@
SET NOCOUNT OFF s/0-DHd
8、说明:更改某个表 9aD6mp
exec sp_changeobjectowner 'tablename','dbo' Fl>v9%A
9、存储更改全部表 KS}Ci-
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch .Ej `!
@OldOwner as NVARCHAR(128), }r3,
fH
@NewOwner as NVARCHAR(128) ?d%+85
AS KYD,eVQ
DECLARE @Name as NVARCHAR(128) oOy@X =cw
DECLARE @Owner as NVARCHAR(128) E,JDO d}
DECLARE @OwnerName as NVARCHAR(128) >^ 0JlL`XG
DECLARE curObject CURSOR FOR cBb!7?6(
select 'Name' = name, fz31di9$
'Owner' = user_name(uid) B 9KY$^J
from sysobjects 5F+5J)h
where user_name(uid)=@OldOwner q]=.Aik
order by name )5_GJm&R9
OPEN curObject t*5d'aE`/
FETCH NEXT FROM curObject INTO @Name, @Owner us\@n"
WHILE(@@FETCH_STATUS=0) n=MdbY/k(
BEGIN I>k3X~cG
if @Owner=@OldOwner (P~Jzp9u
begin Gy.<gyK9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) S;M'qwN
exec sp_changeobjectowner @OwnerName, @NewOwner N*$<Kjw
end x~!B.4gT2
-- select @name,@NewOwner,@OldOwner H@bra~k-
FETCH NEXT FROM curObject INTO @Name, @Owner Bs =V-0
END C_dsYuQ5R
close curObject h`Vb#5ik
deallocate curObject 73P=<3
GO IhwJYPLF
10、SQL SERVER中直接循环写入数据 9~I\WjB
"
declare @i int {J%Na&D
set @i=1 N5#qox$D
while @i<30 ZZA!Y9ia2
begin 4%LG9hS
insert into test (userid) values(@i) L7_(KC h
set @i=@i+1 ZD/>L/
end 9xP{#Qa
小记存储过程中经常用到的本周,本月,本年函数 K20n355uE
Dateadd(wk,datediff(wk,0,getdate()),-1) TDBWYppM
Dateadd(wk,datediff(wk,0,getdate()),6) BWFl8
!_X
Dateadd(mm,datediff(mm,0,getdate()),0) /p~"?9b[ i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \)eHf
7H
Dateadd(yy,datediff(yy,0,getdate()),0) e'[T5HI
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) yGT"k,a
上面的SQL代码只是一个时间段 )|@b
GEk
Dateadd(wk,datediff(wk,0,getdate()),-1) A@bWlwfl
Dateadd(wk,datediff(wk,0,getdate()),6) x9xb4ZW
就是表示本周时间段. &{9'ylv-B)
下面的SQL的条件部分,就是查询时间段在本周范围内的: LG'JQGl5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) I.r&;
而在存储过程中 iC?s`c0B
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) P0~3<h?U8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <Q/^[