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。 @]tGfr;le&
mlWIq]J
@/(7kh+
一、基础 N6[^62
1、说明:创建数据库 .rm7Sd4K
CREATE DATABASE database-name Kx+Bc&X
2、说明:删除数据库 LD~'^+W
drop database dbname fEc_r:|\6
3、说明:备份sql server }x1IFTa!
--- 创建 备份数据的 device G0>Wk#or
USE master IyN9
+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rM=A"
--- 开始 备份 yjR
O9
BACKUP DATABASE pubs TO testBack aF"Z!HD
4、说明:创建新表 piotd,
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hF7mJ\
根据已有的表创建新表: 6<$|;w-OV
A:create table tab_new like tab_old (使用旧表创建新表) JJ0
CM:xe
B:create table tab_new as select col1,col2... from tab_old definition only wT=hO+
5、说明:删除新表 D*gVS
drop table tabname JW[\"`x!
6、说明:增加一个列 ;j>d"i36&
Alter table tabname add column col type
cgeS)C7
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Le
JlTWotC
7、说明:添加主键: Alter table tabname add primary key(col) f {c[_OR
说明:删除主键: Alter table tabname drop primary key(col) :*'?Ac
?
8、说明:创建索引:create [unique] index idxname on tabname(col....) JwtI(>cI
删除索引:drop index idxname
73ljW
注:索引是不可更改的,想更改必须删除重新建。 3F} KrG
9、说明:创建视图:create view viewname as select statement &:#8ol(n5b
删除视图:drop view viewname }n%Rl\p
10、说明:几个简单的基本的sql语句 gA1in
选择:select * from table1 where 范围 ydqmuZ%2h#
插入:insert into table1(field1,field2) values(value1,value2) ]q7 LoH'S
删除:delete from table1 where 范围 G)Bq?=P
更新:update table1 set field1=value1 where 范围 o'C.,ic?C
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U hhmG+
排序:select * from table1 order by field1,field2 [desc] ^!F5Cz 48
总数:select count as totalcount from table1 Su$ 1 t
求和:select sum(field1) as sumvalue from table1 [(F<|f:n
平均:select avg(field1) as avgvalue from table1 dd7nO
:]
最大:select max(field1) as maxvalue from table1 ]U1,NhZu
最小:select min(field1) as minvalue from table1 4`P2FnJ?
Sw@,<4S
vW-`=30
T$8~9qx
11、说明:几个高级查询运算词 "HfU,$[
{ah~q}(P
tZCe?n]
A: UNION 运算符 sVdK^|j
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。 ?EQ^n3U$
B: EXCEPT 运算符 3e6Y
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。 `N.$LY;8
C: INTERSECT 运算符 eoe^t:5&
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Qr%Jm{_o
注:使用运算词的几个查询结果行必须是一致的。 >[fVl8G_0
12、说明:使用外连接 zHOE.V2Qo
A、left outer join: HU[nN*
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 |z]2KjF&w-
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :t{vgi D9
B:right outer join: }R&5qpl
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ]z=Vc#+!
C:full outer join: ?g;ZbD
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。
pl,Z
n`z+ w*
^%%5
二、提升 >-@ U_p
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "SU-^z
法一:select * into b from a where 1<>1 e_c;D2'F
法二:select top 0 * into b from a 5J+V:Xu{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }j(2Dl
insert into b(a, b, c) select d,e,f from b; .`&/QiD
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) {I-a;XBX
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k
gu[!hD1
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. nlebFDb7
4、说明:子查询(表名1:a 表名2:b) C{hcK 1-K
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) M1^C8cz
5、说明:显示文章、提交人和最后回复时间 soq".+Q
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %L13Jsw
6、说明:外连接查询(表名1:a 表名2:b) l \^nC2
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +Sd,l>8\
7、说明:在线视图查询(表名1:a ) G(0y|Eq
select * from (SELECT a,b,c FROM a) T where t.a > 1; i`KZ,
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Ryq"\Q>+
select * from table1 where time between time1 and time2 4SffP/
select a,b,c, from table1 where a not between 数值1 and 数值2 loUl$X.u
9、说明:in 的使用方法 fEw=I7{Y
select * from table1 where a [not] in ('值1','值2','值4','值6') y /:T(tk$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 $C05iD
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) L=HVdeE
11、说明:四表联查问题: ?5yH'9zE
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... sjzXJ`s
12、说明:日程安排提前五分钟提醒 {y:#'n
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 p=~h|(M|
13、说明:一条sql 语句搞定数据库分页 l/ rZcf8z
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 F%#*U82
14、说明:前10条记录 !-5S8b
select top 10 * form table1 where 范围 3K#mF7)a
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) fcE)V#c"g
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) j:e^7|.
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 `N,Vs n"
(select a from tableA ) except (select a from tableB) except (select a from tableC) 5{ FM#@
17、说明:随机取出10条数据 [Yy\>
select top 10 * from tablename order by newid() B80odU&
18、说明:随机选择记录 W~u
select newid() f' '{.L
19、说明:删除重复记录 mUt,Z^ l`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) t*a*v;iz
20、说明:列出数据库里所有的表名 t{X?PF\>o
select name from sysobjects where type='U' O*rmD<L$
21、说明:列出表里的所有的 v<%kd[N
select name from syscolumns where id=object_id('TableName') ^'7C0ps+A
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。 \+{t4Im
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 r9]
rN
显示结果: v:"m
type vender pcs fi&uB9hc
电脑 A 1 c3V]'~
电脑 A 1 2>$F0
M
光盘 B 2 ?]W~ qgA
光盘 A 2 Xn/ n|[
手机 B 3 `.>k)=F&
手机 C 3 L%WME8PB
23、说明:初始化表table1 afY _9g!\
TRUNCATE TABLE table1 *"5N>F[L
24、说明:选择从10到15的记录 $,KP]~?
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc mLg{6qm(q
2gwZb/'i
B` *f(
GOf`Z'\xt
三、技巧 {Vxc6,=
1、1=1,1=2的使用,在SQL语句组合时用的较多 &"[)s[m+t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ak6MPuBB-
如:
+mc[S
if @strWhere !='' DikdC5>O>m
begin TX23D)CX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ={`CHCI
end V#NG+U.B
else D1X4|Q*SK
begin 0iJ!K;A2%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _~;&)cn,0
end AfRW=&xdT
我们可以直接写成 X&(<G
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *K(k Kph
2、收缩数据库 +}^|dkc
--重建索引 E.J0fwyT
DBCC REINDEX z.3<{-n}0i
DBCC INDEXDEFRAG ;8ET!&k*>E
--收缩数据和日志 ?< cM^$lI>
DBCC SHRINKDB
@~k5+Z
DBCC SHRINKFILE 6Wpxp\
3、压缩数据库 WR/o
@$/
dbcc shrinkdatabase(dbname) T-|9o|~z
4、转移数据库给新用户以已存在用户权限 gB>imr#e&
exec sp_change_users_login 'update_one','newname','oldname' sno`=+|U]
go ~)q g
5、检查备份集 \ ]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 'qL5$ zG
6、修复数据库 !K3})& w
ALTER DATABASE [dvbbs] SET SINGLE_USER 5@`F.F>"
GO 38c?^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK y=AsgJ
GO e}42/>}#D
ALTER DATABASE [dvbbs] SET MULTI_USER M{?.hq
GO |h&<_9
7、日志清除 "l@A[@R
SET NOCOUNT ON qoj^_s6
DECLARE @LogicalFileName sysname, bMN@H\Ek
@MaxMinutes INT, /!GKh5|
@NewSize INT
7%}ay
USE tablename -- 要操作的数据库名 e~{^oM
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 FR
x6c
@MaxMinutes = 10, -- Limit on time allowed to wrap log. E *F*nd]K
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9>by~4An?
-- Setup / initialize &{%MjKJ._
DECLARE @OriginalSize int Ia629gi5s
SELECT @OriginalSize = size `)R?nVb
FROM sysfiles AF^T~?t
WHERE name = @LogicalFileName RU2c*q$^X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + xvU]jl6d
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + d0(Cn}m"c
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <B6[i*&
FROM sysfiles c$0_R;4/
WHERE name = @LogicalFileName P+<BOG|m
CREATE TABLE DummyTrans ^P`NMSw
(DummyColumn char (8000) not null) ,;_rIO"
DECLARE @Counter INT, egm)a
@StartTime DATETIME, P|e`^Frxt
@TruncLog VARCHAR(255) pDu{e>S|:
SELECT @StartTime = GETDATE(), *AZ?~ i^o
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v`JF\"}S
DBCC SHRINKFILE (@LogicalFileName, @NewSize) N.Dhu ~V
EXEC (@TruncLog) *E:x E/M!2
-- Wrap the log if necessary. qmZ2d!)o
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ddsUz1%l
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 0$6*o}N%
AND (@OriginalSize * 8 /1024) > @NewSize *5'.!g('
BEGIN -- Outer loop. [oV{83f
SELECT @Counter = 0 bpCNho$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #(C/Cx54
BEGIN -- update ;UYc
INSERT DummyTrans VALUES ('Fill Log') `} =yG_!A
DELETE DummyTrans g\Wj+el}
SELECT @Counter = @Counter + 1 9UwLF`XM
END 8j%'9vPi
EXEC (@TruncLog) Sw)i1S9
END ncv7t|ZN
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !z"Nv1!~|
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?"6Ov ]
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ueDvMP
FROM sysfiles St@l]u9
WHERE name = @LogicalFileName e}A&V+
DROP TABLE DummyTrans t<nFy
SET NOCOUNT OFF c-kA^z{f
8、说明:更改某个表 GnFs63
exec sp_changeobjectowner 'tablename','dbo' wW:7y>z)
9、存储更改全部表 Wta]BX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~-TOsRvxR
@OldOwner as NVARCHAR(128), 8pXKO"u],
@NewOwner as NVARCHAR(128) 1,,|MW
AS ak;6z]f8[
DECLARE @Name as NVARCHAR(128) L=O lyHO
DECLARE @Owner as NVARCHAR(128) +\0T\;-Xe
DECLARE @OwnerName as NVARCHAR(128) OL'P]=U
DECLARE curObject CURSOR FOR \fZiL!E^7
select 'Name' = name, c'Z:9?#5
'Owner' = user_name(uid) B^fT>1P
from sysobjects Z!6UW:&~7
where user_name(uid)=@OldOwner )RN<GW'
order by name ebC)H
OPEN curObject KOey8tB)1
FETCH NEXT FROM curObject INTO @Name, @Owner %-+j
WHILE(@@FETCH_STATUS=0) GIT#<+"
BEGIN IG< H"tQ
if @Owner=@OldOwner J8?2R^;{
begin n9%]-s\Hn
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5t\HJ`C1Z
exec sp_changeobjectowner @OwnerName, @NewOwner u%u&F^y
end _;hf<|c
-- select @name,@NewOwner,@OldOwner OfTfNhpK
FETCH NEXT FROM curObject INTO @Name, @Owner 5RF4]$zT
END 0,_b)
close curObject ;o0#(xVz
deallocate curObject %@?A_jS
GO TVaA>]Fv
10、SQL SERVER中直接循环写入数据 kA4@`YCl
declare @i int *6Q|}b[qcD
set @i=1 +r]zs^'
while @i<30 ~`qEWvPn
begin |7"$ w%2
insert into test (userid) values(@i) u%3i0BajY
set @i=@i+1 5\bJR0I@
end T%$jWndI
小记存储过程中经常用到的本周,本月,本年函数 !^w
E/
Dateadd(wk,datediff(wk,0,getdate()),-1) x5h~G
Dateadd(wk,datediff(wk,0,getdate()),6) DkDoA;m
Dateadd(mm,datediff(mm,0,getdate()),0) k?*KnfVh!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) _ \D"E>oM
Dateadd(yy,datediff(yy,0,getdate()),0) nirDMw[
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1vnYogL
上面的SQL代码只是一个时间段 ,
sjh^-;
Dateadd(wk,datediff(wk,0,getdate()),-1) Zd!U')5/
Dateadd(wk,datediff(wk,0,getdate()),6) OcmRZ
就是表示本周时间段. *27*>W1
下面的SQL的条件部分,就是查询时间段在本周范围内的: Es!Q8.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) kGHQ`h
而在存储过程中 jq-l5})h
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) eF~dQ4RZ
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xwi\