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。 TqbKH08i/
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一、基础 -QS_bQG%
1、说明:创建数据库 ,rX!V=Z5
CREATE DATABASE database-name <Bu*: O
2、说明:删除数据库 $$qhX]^~
drop database dbname J)g(Nw,O
3、说明:备份sql server _5y)m5I
--- 创建 备份数据的 device PrN?;Z.
USE master pm )A*][s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X#eVw|
--- 开始 备份 p3^7Hr
BACKUP DATABASE pubs TO testBack b: %>TPT
4、说明:创建新表 /h2`?~k+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) O4$:
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根据已有的表创建新表: u%*;gu"2
A:create table tab_new like tab_old (使用旧表创建新表) 'inWV* P*g
B:create table tab_new as select col1,col2... from tab_old definition only I/^Lr_\
5、说明:删除新表 ?'_iqg3
drop table tabname NpRC3^
6、说明:增加一个列 L7Skn-*tnA
Alter table tabname add column col type (x=NA
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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。 Mu:*(P/
7、说明:添加主键: Alter table tabname add primary key(col) #lVVSrF,-
说明:删除主键: Alter table tabname drop primary key(col) OH=Ffy F,
8、说明:创建索引:create [unique] index idxname on tabname(col....) PwDQ<
删除索引:drop index idxname ?on3z
注:索引是不可更改的,想更改必须删除重新建。 b$gDFNa
9、说明:创建视图:create view viewname as select statement S%%>&^5
删除视图:drop view viewname 6K<vyr40
10、说明:几个简单的基本的sql语句 j@9nX4Z
选择:select * from table1 where 范围 l_f"}l
插入:insert into table1(field1,field2) values(value1,value2) H
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删除:delete from table1 where 范围 >/'WU79TYE
更新:update table1 set field1=value1 where 范围 `C!Pe84(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @69q// #B
排序:select * from table1 order by field1,field2 [desc] T@Q.m.iV4
总数:select count as totalcount from table1 $V\xN(Ed
求和:select sum(field1) as sumvalue from table1 BwBv'p+n
平均:select avg(field1) as avgvalue from table1 t<: XY
最大:select max(field1) as maxvalue from table1 T_gW't>
最小:select min(field1) as minvalue from table1 ruE.0V I@
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11、说明:几个高级查询运算词 g" M1HxlV
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A: UNION 运算符 #vS>^OyP
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。 3d,|26I 7f
B: EXCEPT 运算符 H<FDi{
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。 l{y~N
C: INTERSECT 运算符 %|,j'V$
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。 fk",YtS*
注:使用运算词的几个查询结果行必须是一致的。 7`WK1_rR\
12、说明:使用外连接 ;2X1 qw>
A、left outer join: xSLN
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。 wL%>
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 zizrc.g/Yg
B:right outer join: 0q62 {p7
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。 +5T0]!
C:full outer join: 6xj&Qo
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。 1[}VyP6 e
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二、提升 s'K0C8'U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +"d{P,[3J
法一:select * into b from a where 1<>1 I.(
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法二:select top 0 * into b from a "+HZ~:~f
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4z$eT
insert into b(a, b, c) select d,e,f from b; b9\=NdyCY
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) lR-4"/1|y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 8`*`4m
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *np%67=jO
4、说明:子查询(表名1:a 表名2:b) 12rr:(#%s
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) @w|~:>/g
5、说明:显示文章、提交人和最后回复时间 k'u2a
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #U6Wv1H{Lp
6、说明:外连接查询(表名1:a 表名2:b) ;>Kxl}+R
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *.~M#M 9c
7、说明:在线视图查询(表名1:a ) zfxxPL'
select * from (SELECT a,b,c FROM a) T where t.a > 1; KD#ip3
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 \GPWC}V\s
select * from table1 where time between time1 and time2 m$$U%=r>@
select a,b,c, from table1 where a not between 数值1 and 数值2 naAZR*(A
9、说明:in 的使用方法 2j_L
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select * from table1 where a [not] in ('值1','值2','值4','值6') {cG&l:-r
10、说明:两张关联表,删除主表中已经在副表中没有的信息 5qFqH
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) >+G=|2
11、说明:四表联查问题: Z?^AX&F
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 ..... b2:CFtH5
12、说明:日程安排提前五分钟提醒 7,
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]C'r4Ch^
13、说明:一条sql 语句搞定数据库分页 /h
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 ,NVQ C=
14、说明:前10条记录 Z4rK$B
select top 10 * form table1 where 范围 =MoPOib\n
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.) 8# 9.a]AX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) *VL-b8'A<
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 LdRLKE<'e
(select a from tableA ) except (select a from tableB) except (select a from tableC) Qy9#(596
17、说明:随机取出10条数据 OvQG%D}P=
select top 10 * from tablename order by newid() 'jfI1 ]q
18、说明:随机选择记录 a7M8sZ?"
select newid() iXXgPapz
19、说明:删除重复记录 JZai{0se
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) .+ _x|?'
20、说明:列出数据库里所有的表名 ON!1lS
select name from sysobjects where type='U' %)]{*#N4
21、说明:列出表里的所有的 [dUW3}APV
select name from syscolumns where id=object_id('TableName') H'2pmwk
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。 $e0sa=/
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type AC
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显示结果: =G*<WcR
type vender pcs m}8c.OJ>K`
电脑 A 1 Thz&wH`W
电脑 A 1 E*k=8$Y
光盘 B 2 G0<m3 Up
光盘 A 2 CbwQ'c$}
手机 B 3 C~kw{g+|
手机 C 3 6R"& !.ZF
23、说明:初始化表table1 EXo"F*gW
TRUNCATE TABLE table1 \GBv@
24、说明:选择从10到15的记录 x.}iSE{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Uv.{=H:
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三、技巧 $,bLb5}Qu
1、1=1,1=2的使用,在SQL语句组合时用的较多 *y u|]T
"where 1=1" 是表示选择全部 "where 1=2"全部不选, hfVJg7-
如: 9D-PmSnv
if @strWhere !='' `43E-'g
begin \vpUl
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -R|v&h%T
end !.kj-==s{7
else _PQQ&e)E
begin F DXAe-|Q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' {QJJw}!#
end td{$c6
我们可以直接写成 [&"`2n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere SmC91XO
2、收缩数据库 kOeW,:&65
--重建索引 EtKy?]i
DBCC REINDEX M/ >^_zG
DBCC INDEXDEFRAG 1XL^Zhr
--收缩数据和日志 MT}9T
DBCC SHRINKDB a$"3T
DBCC SHRINKFILE w8$8P
3、压缩数据库 qK,rT*5=
dbcc shrinkdatabase(dbname) Me2%X>;
4、转移数据库给新用户以已存在用户权限 Np+<)q2
exec sp_change_users_login 'update_one','newname','oldname' {0QNqjue
go
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5、检查备份集 =5',obYN>c
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :[,-wZiT~6
6、修复数据库 D8G5,s-.
ALTER DATABASE [dvbbs] SET SINGLE_USER ;MR8E9
GO f{G
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AwUc U;"9>
GO ;",W&HQbE
ALTER DATABASE [dvbbs] SET MULTI_USER !w{4FE74
GO Wi)Y9frE
7、日志清除 q\/ph(HF
SET NOCOUNT ON 'HzF/RKh
DECLARE @LogicalFileName sysname, 5{L~e>oS9
@MaxMinutes INT, ]]V|[g&aJ
@NewSize INT 6 -N 442
USE tablename -- 要操作的数据库名 (gQP_Oa(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Rcc9Tx(zvQ
@MaxMinutes = 10, -- Limit on time allowed to wrap log. xo
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@NewSize = 1 -- 你想设定的日志文件的大小(M) 3c}@_Yn
-- Setup / initialize f;x0Ho5C2
DECLARE @OriginalSize int Jx!#y A;
SELECT @OriginalSize = size YZMSiDv[e
FROM sysfiles xG/B$DLn
WHERE name = @LogicalFileName :Ugf3%sQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + kZ>_m&g
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + X @RS
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [+
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FROM sysfiles _ VKBzOH
WHERE name = @LogicalFileName C6Lc
CREATE TABLE DummyTrans =;ClOy9
(DummyColumn char (8000) not null) i}[cq_wJ
DECLARE @Counter INT, j4k\5~yzS
@StartTime DATETIME, gF#HNv
@TruncLog VARCHAR(255) Py y!B
SELECT @StartTime = GETDATE(), tp*.'p-SI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :m]H?vq] \
DBCC SHRINKFILE (@LogicalFileName, @NewSize) T\?$7$/V
EXEC (@TruncLog) .o8Sy2PaV
-- Wrap the log if necessary. 0"}J!c<g
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired kOdXbw9v
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -M5vh~Tp
AND (@OriginalSize * 8 /1024) > @NewSize iO+,U} &
BEGIN -- Outer loop. {7'Wi$^F
SELECT @Counter = 0 }IEwGoDwNs
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) =h0vdi%{
BEGIN -- update :e/*5ix
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans 4a}[&zm(5
SELECT @Counter = @Counter + 1 hz:h>Hwy
END i'V("
EXEC (@TruncLog) _rM?g1}5j
END 2,aH1Xbex
SELECT 'Final Size of ' + db_name() + ' LOG is ' + /s*.:cdH
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e`n+U-)z
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' _Z7`tUS-j
FROM sysfiles ;`Nh@*_
WHERE name = @LogicalFileName h?[|1.lJx(
DROP TABLE DummyTrans ~-R%m
SET NOCOUNT OFF mC2K &'[
8、说明:更改某个表 ~(nc<M[
exec sp_changeobjectowner 'tablename','dbo' 76H>ST@G|
9、存储更改全部表 >Q$ph=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |;:g7eb
@OldOwner as NVARCHAR(128), dq,j?~ _}
@NewOwner as NVARCHAR(128) Yw] 7@
AS v{d$DZUs
DECLARE @Name as NVARCHAR(128) Ps!umV
DECLARE @Owner as NVARCHAR(128) TZ&X0x8
DECLARE @OwnerName as NVARCHAR(128) 6_,JW{#"
DECLARE curObject CURSOR FOR 0civXZgj
select 'Name' = name, Y<L35
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'Owner' = user_name(uid) L4,b ThSG
from sysobjects HS[($
where user_name(uid)=@OldOwner Q2/65$nW
order by name /sfJ:KP0
OPEN curObject ])}a^]0q
FETCH NEXT FROM curObject INTO @Name, @Owner m??Py"1y
WHILE(@@FETCH_STATUS=0) G %'xEr0n
BEGIN L!>nl4O>`
if @Owner=@OldOwner ~8s2p%~
begin <d @9[]
set @OwnerName = @OldOwner + '.' + rtrim(@Name) >-w(P/
exec sp_changeobjectowner @OwnerName, @NewOwner $=iw<B r
end _%q~K (::
-- select @name,@NewOwner,@OldOwner Jsl2RdI
FETCH NEXT FROM curObject INTO @Name, @Owner c
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END >
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close curObject >H^#!eaqw
deallocate curObject e2f+Fv
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GO v3#,Z!
10、SQL SERVER中直接循环写入数据 8Qo'[+4;
declare @i int 6<EGH*GQ$
set @i=1 q`,%L1c4
while @i<30 [Ur\^wS
begin Y{D%v
insert into test (userid) values(@i) ~wa6S?
set @i=@i+1 QF)\\D[
end @/F61Ut
小记存储过程中经常用到的本周,本月,本年函数 K>dB{w#gS
Dateadd(wk,datediff(wk,0,getdate()),-1) om`T/@_,
Dateadd(wk,datediff(wk,0,getdate()),6) D"rbQXR7$
Dateadd(mm,datediff(mm,0,getdate()),0) t;BUZE_!0c
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }x?F53I)
Dateadd(yy,datediff(yy,0,getdate()),0) MjU|XQS:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V(_1q
上面的SQL代码只是一个时间段 B*N1)J\5
Dateadd(wk,datediff(wk,0,getdate()),-1) y(o)}m*0
Dateadd(wk,datediff(wk,0,getdate()),6) p}^5ru
就是表示本周时间段. RFMPh<Ac
下面的SQL的条件部分,就是查询时间段在本周范围内的: =e4 r=I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |~r-VV(=
而在存储过程中 i|J%jA
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) <XIIT-b[
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qT48Y