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。 $^/0<i$
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一、基础 ],etZ%z&
1、说明:创建数据库 C)-^<
CREATE DATABASE database-name \*vHB`.,ey
2、说明:删除数据库 Nh?|RE0t
drop database dbname QbFHfA2Ij
3、说明:备份sql server q<vf,D@{ !
--- 创建 备份数据的 device I&yVx8aH}
USE master Wzq>JNny
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' c~}l8M%
--- 开始 备份 Tb;d.^
BACKUP DATABASE pubs TO testBack upn~5>uCP
4、说明:创建新表 >pyj]y^3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) J97R0
根据已有的表创建新表: koG{
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A:create table tab_new like tab_old (使用旧表创建新表) ]$-cMX
B:create table tab_new as select col1,col2... from tab_old definition only 8TV;Rtl
5、说明:删除新表 ed 59B)?l
drop table tabname Q[n\R@
6、说明:增加一个列 DPgm%Xq9(!
Alter table tabname add column col type 6c4&VW
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 'fV%Z
7、说明:添加主键: Alter table tabname add primary key(col) {Bvj"mL]j
说明:删除主键: Alter table tabname drop primary key(col) 5v.DX`"
8、说明:创建索引:create [unique] index idxname on tabname(col....) <~U4*
删除索引:drop index idxname gwkb!#A
注:索引是不可更改的,想更改必须删除重新建。 |H}sYp
9、说明:创建视图:create view viewname as select statement 66&EBX}
删除视图:drop view viewname >zvY\{WY
10、说明:几个简单的基本的sql语句 IV16d
选择:select * from table1 where 范围 RSfM]w}Hq#
插入:insert into table1(field1,field2) values(value1,value2) +ZsX*/TOn
删除:delete from table1 where 范围 Z$KLl((
更新:update table1 set field1=value1 where 范围 -!M,75nU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g:ErZ;[
排序:select * from table1 order by field1,field2 [desc] 's?Ai2=#
总数:select count as totalcount from table1 Nt`b;X&
求和:select sum(field1) as sumvalue from table1 ;#+0L$<t
平均:select avg(field1) as avgvalue from table1 G#`\(NW
最大:select max(field1) as maxvalue from table1 _cH@I?B
最小:select min(field1) as minvalue from table1 b}9[s
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11、说明:几个高级查询运算词 z$lF)r:Bc
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A: UNION 运算符 Lm*VN~2
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。 CJknJn3m&
B: EXCEPT 运算符 I+
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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。 ^>&k]T`
C: INTERSECT 运算符 NUJ~YWO;
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。 Wl"0m1G
注:使用运算词的几个查询结果行必须是一致的。 t G.(flW,
12、说明:使用外连接 m4w')r~
A、left outer join: jn%kG ~]'Q
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。 F!!N9VIC
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 o5o^TW{
B:right outer join: w FtN+
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。 V\~Wv V
C:full outer join: oP?YA-#nc
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。 OKOu`Hz@
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二、提升 1^J`1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) EpPf_ \o
法一:select * into b from a where 1<>1 5~
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法二:select top 0 * into b from a *ZSdl0e
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) A~(l{g
insert into b(a, b, c) select d,e,f from b; 2(!fg4#+
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) KU9Z"9#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Rf %HIAVE
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hjx)D
4、说明:子查询(表名1:a 表名2:b) |+IZS/W"
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)
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5、说明:显示文章、提交人和最后回复时间 w) ]H ^6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4 {GU6v)f
6、说明:外连接查询(表名1:a 表名2:b) F51.N{'
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C_fY %O
7、说明:在线视图查询(表名1:a ) V,v[y\
select * from (SELECT a,b,c FROM a) T where t.a > 1; f7de'^t9
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 zzGYiF?
select * from table1 where time between time1 and time2 I8Vb-YeS
select a,b,c, from table1 where a not between 数值1 and 数值2 <3X7T6_:@
9、说明:in 的使用方法 Rhzn/\)|
select * from table1 where a [not] in ('值1','值2','值4','值6') T5Eseesp
10、说明:两张关联表,删除主表中已经在副表中没有的信息 iX{G]< n
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1t[j"CG(o
11、说明:四表联查问题: 9a$56GnW1
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... {NM+Oj,~'
12、说明:日程安排提前五分钟提醒 )QiQn=Ce
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,SlN zR
13、说明:一条sql 语句搞定数据库分页 0o&MB
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 =4!nFi
14、说明:前10条记录 "O>n@Q|
select top 10 * form table1 where 范围 1r)kR@!LNG
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) YA(@5CZ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8G%yB}pa
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 )x,8D ~p'
(select a from tableA ) except (select a from tableB) except (select a from tableC) O{z}8&oR:
17、说明:随机取出10条数据 n";02?@F
select top 10 * from tablename order by newid() ,"}Rg1\4t
18、说明:随机选择记录 *~$~yM/~3U
select newid() { >{B`e`$
19、说明:删除重复记录 _A_ A$N~9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) p\vMc\
20、说明:列出数据库里所有的表名 gieJ}Bv
select name from sysobjects where type='U' ]1-z!B 4K
21、说明:列出表里的所有的 =TvzS%U
select name from syscolumns where id=object_id('TableName') ITuq/qts]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。 cF T 9Lnz
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 {4 >mc'dv
显示结果: bEuaOBc
type vender pcs R!
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电脑 A 1 %!Q`e79g8
电脑 A 1 N@o?b
光盘 B 2 xh@-g|+g
光盘 A 2 eBN)g^
手机 B 3 _#$9 y1bd
手机 C 3 3#kitmV
23、说明:初始化表table1 g\A
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TRUNCATE TABLE table1 YMpf+kN
24、说明:选择从10到15的记录 \6|/RFT
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,FQdtNMap
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三、技巧 %T`U^Pnr
1、1=1,1=2的使用,在SQL语句组合时用的较多 jMBiaX`F
"where 1=1" 是表示选择全部 "where 1=2"全部不选, l?E a#
如: SJ'
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if @strWhere !='' 7[v%GoE
begin +m\|e{G
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }peBR80tQ
end [BbutGvj
else 1MkI0OZE
begin XhU@W}}
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' T".]m7!
end 9$K;Raz%
我们可以直接写成 -7>)i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9|'B9C
2、收缩数据库 }71LLzG`/
--重建索引 /Poet%XvRx
DBCC REINDEX (3vHY`9
DBCC INDEXDEFRAG &7?R+ZGo
--收缩数据和日志 DsD zkwJE
DBCC SHRINKDB z;u>
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DBCC SHRINKFILE 0CvsvUN@
3、压缩数据库 z T%U!jqI
dbcc shrinkdatabase(dbname) yTM{|D]$(
4、转移数据库给新用户以已存在用户权限 L7Dh(y=;7
exec sp_change_users_login 'update_one','newname','oldname' .?C%1a&_l
go #>;FUZuJr
5、检查备份集 }7<5hn E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Zwt; d5U
6、修复数据库 D6D1S/:ij'
ALTER DATABASE [dvbbs] SET SINGLE_USER Z~G my7h(
GO PnT)LqEF
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &FdWFt=X
GO gA#RM5x@
ALTER DATABASE [dvbbs] SET MULTI_USER {Ng oYl
GO )+I.|5g
7、日志清除 @# P0M--X
SET NOCOUNT ON vP!GJX&n5
DECLARE @LogicalFileName sysname, iSK+GQ~
@MaxMinutes INT, D.!~dyI.,$
@NewSize INT ytEC
USE tablename -- 要操作的数据库名 GDaN
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 >/f_F6ay#
@MaxMinutes = 10, -- Limit on time allowed to wrap log. PrF}a<:n:
@NewSize = 1 -- 你想设定的日志文件的大小(M) tEd.'D8 s
-- Setup / initialize sf}Dh
DECLARE @OriginalSize int %u{W7
SELECT @OriginalSize = size JD>d\z2QC
FROM sysfiles [ Mg8/Oy
WHERE name = @LogicalFileName 2pHR_mrb
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,n,RFa
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + I 1d0iU
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' yKagT$-
FROM sysfiles =?0lA_
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WHERE name = @LogicalFileName $L4/I !Yf
CREATE TABLE DummyTrans 5vzceQE}
(DummyColumn char (8000) not null) E&$_`m;
DECLARE @Counter INT, v'2[[u{7*
@StartTime DATETIME, 4\t1mocCSN
@TruncLog VARCHAR(255) W~T}@T:EN
SELECT @StartTime = GETDATE(), #PvB/3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Q3W#`6jpF
DBCC SHRINKFILE (@LogicalFileName, @NewSize) EC&@I+'8Q
EXEC (@TruncLog) ;|%dY{L-
-- Wrap the log if necessary. ;E2>Ovv
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired YEu1#N
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [t\B6XxT
AND (@OriginalSize * 8 /1024) > @NewSize }n,Zl>T9
BEGIN -- Outer loop. Myat{OF
SELECT @Counter = 0 dth&?/MERL
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5@Bu99`
BEGIN -- update ]36sZ
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INSERT DummyTrans VALUES ('Fill Log') qr\!*\9
DELETE DummyTrans I<b?vR 'F
SELECT @Counter = @Counter + 1 VvbFp
END <<A`aU^fX
EXEC (@TruncLog) ;#G oGb4AM
END +eX)48
SELECT 'Final Size of ' + db_name() + ' LOG is ' + tL
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + X8eJ4%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' A?Q a 4i
FROM sysfiles 3q[WHwmm
WHERE name = @LogicalFileName W|k0R4K]]
DROP TABLE DummyTrans ~%u|[$
SET NOCOUNT OFF $S*4r&8ZD
8、说明:更改某个表 hlZ@Dq%f
exec sp_changeobjectowner 'tablename','dbo' UAF<m1
9、存储更改全部表 $$Vt7"F
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _;A $C(
@OldOwner as NVARCHAR(128), ~Aad9yyi
@NewOwner as NVARCHAR(128) _STB$cZ
AS [//R ~i?
DECLARE @Name as NVARCHAR(128) 6!iJ;1PeE
DECLARE @Owner as NVARCHAR(128) C8N{l:1f]
DECLARE @OwnerName as NVARCHAR(128) uNbH\qd=
DECLARE curObject CURSOR FOR gQSNU_o Z
select 'Name' = name, Vpfp}pL
'Owner' = user_name(uid) #BK 9 k>i
from sysobjects xynw8;Y,
where user_name(uid)=@OldOwner C9n}6Er=,
order by name jt~Qu-
OPEN curObject 5pNY)>]t=
FETCH NEXT FROM curObject INTO @Name, @Owner '+'CbWgY
WHILE(@@FETCH_STATUS=0) <<9Va.
BEGIN !
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if @Owner=@OldOwner I[MgIr^
begin h 6G/O`:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) >>[/UFC)n
exec sp_changeobjectowner @OwnerName, @NewOwner jcCoan
end \hO2p6
-- select @name,@NewOwner,@OldOwner O/%< }3Sq
FETCH NEXT FROM curObject INTO @Name, @Owner fqz28aHh
END C`rLj5E%
close curObject e)nimq
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deallocate curObject G |*(8r()
GO 1RLY $M
10、SQL SERVER中直接循环写入数据 WlB'YL-`g
declare @i int ;P &y,:<m:
set @i=1 $$i.O}
while @i<30 .o%^'m"=D[
begin )o1eWL}
insert into test (userid) values(@i) j83? m
set @i=@i+1 {eJt,[Y *
end X C86-b)E
小记存储过程中经常用到的本周,本月,本年函数 z@s5m}
Dateadd(wk,datediff(wk,0,getdate()),-1) O40+M)e]
Dateadd(wk,datediff(wk,0,getdate()),6) fjo{av~]y
Dateadd(mm,datediff(mm,0,getdate()),0) {C`GW}s{4
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 3OyS8`
Dateadd(yy,datediff(yy,0,getdate()),0)
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) _eSdnHWx
上面的SQL代码只是一个时间段 LVIAF0kX
Dateadd(wk,datediff(wk,0,getdate()),-1) q:>^ "P{
Dateadd(wk,datediff(wk,0,getdate()),6) |as!Ui/J/
就是表示本周时间段. S&O3HC
下面的SQL的条件部分,就是查询时间段在本周范围内的: p]D]:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Op.8a`XLt&
而在存储过程中 S-+"@>{HJ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) s6*ilq1
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) .%EL \2