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。 [UXVL}tk
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一、基础 7Y@]o=DIc
1、说明:创建数据库 ZOfv\(iJ;
CREATE DATABASE database-name UUfM7gq
2、说明:删除数据库 N-2#-poDe
drop database dbname <2]h$53y!
3、说明:备份sql server YA@?L!F
--- 创建 备份数据的 device 0\!Bh^++1
USE master &C
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' A]m*~Vj]
--- 开始 备份 liYsUmjZ=
BACKUP DATABASE pubs TO testBack 9c]$d
4、说明:创建新表 sP^:*B0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) >e!J(4.-
根据已有的表创建新表: O83J[YuzjN
A:create table tab_new like tab_old (使用旧表创建新表) <y?+xZM]#|
B:create table tab_new as select col1,col2... from tab_old definition only -I{op
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5、说明:删除新表 w
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drop table tabname gWHY7rv
6、说明:增加一个列 4OM
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Alter table tabname add column col type e-`9-U%6
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。 a"P &
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7、说明:添加主键: Alter table tabname add primary key(col) iyCH)MA
说明:删除主键: Alter table tabname drop primary key(col) mIf)=RW
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q#yHH]U)X
删除索引:drop index idxname ij]~n
注:索引是不可更改的,想更改必须删除重新建。 Lfx a^0
9、说明:创建视图:create view viewname as select statement Fb<'L5}i
删除视图:drop view viewname l1zPL3"u_^
10、说明:几个简单的基本的sql语句 G$YF0Nc
选择:select * from table1 where 范围 XC6 |<pru
插入:insert into table1(field1,field2) values(value1,value2) MMjewGxe
删除:delete from table1 where 范围 H$?MPA-c
更新:update table1 set field1=value1 where 范围 +xIVlH9`Q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *8qRdI9
排序:select * from table1 order by field1,field2 [desc] =UO7!vr;[
总数:select count as totalcount from table1 I SZEP8w
求和:select sum(field1) as sumvalue from table1 Z]LP18m9kl
平均:select avg(field1) as avgvalue from table1 Z5rL.a&
最大:select max(field1) as maxvalue from table1 ~Fvz&dO
最小:select min(field1) as minvalue from table1 wIRU!lIF9
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11、说明:几个高级查询运算词 UBv#z&@[
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A: UNION 运算符 g NE"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。 g[b;1$
B: EXCEPT 运算符 dn~k_J=p
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。 T:'<:*pD
C: INTERSECT 运算符
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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。 @?tR-L<u
注:使用运算词的几个查询结果行必须是一致的。 ;YokPiBy
12、说明:使用外连接 Y"5FK
A、left outer join: /FTP8XHwL)
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。 kazgI>"Q8
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 ]S(nA!]
B:right outer join: t:.X=/02
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;z+E_sQ
C:full outer join: ,UVd+rY}
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。 Tpnwwx[]:|
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二、提升 KdlUa^}D
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) }+NlYD:qF
法一:select * into b from a where 1<>1 A@.ruG$
法二:select top 0 * into b from a Ki:98a$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *Q-uE
insert into b(a, b, c) select d,e,f from b; r,,* k E
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) jxw8jo06:
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 jRk1Iu| 7
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +^,&z}(
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4、说明:子查询(表名1:a 表名2:b) v{SYz<(
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) 'Um\m
5、说明:显示文章、提交人和最后回复时间 U&+lw=
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X=Y>9
6、说明:外连接查询(表名1:a 表名2:b) pkIJbI{aS
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !q+
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7、说明:在线视图查询(表名1:a ) ]x_14$rk
select * from (SELECT a,b,c FROM a) T where t.a > 1; >Co@K^'
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 I7#+B1t
select * from table1 where time between time1 and time2 65c#he[_Y
select a,b,c, from table1 where a not between 数值1 and 数值2 _rUsb4r
9、说明:in 的使用方法 AIQ]lQ(
select * from table1 where a [not] in ('值1','值2','值4','值6') 7&dPrnQX=
10、说明:两张关联表,删除主表中已经在副表中没有的信息 / vzwokH
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) o[G,~f\-
11、说明:四表联查问题: s\
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... b\"2O4K,)
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }PzYt~Z`@
13、说明:一条sql 语句搞定数据库分页 4mWT"T-8
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 {<^PYN>`
14、说明:前10条记录 (@*#Pn|A
select top 10 * form table1 where 范围 J}&xS<
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) s9YP
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /I#SP/M&l
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ""F'Nzy
(select a from tableA ) except (select a from tableB) except (select a from tableC) 0'y3iar
17、说明:随机取出10条数据 ~ @s$
select top 10 * from tablename order by newid() <+7-^o_
18、说明:随机选择记录 "(y| iS$^T
select newid() WXE{uGc
19、说明:删除重复记录 b"#|0d0
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) gcs8Gl2
20、说明:列出数据库里所有的表名 H!{Cr#=
select name from sysobjects where type='U' %xI,A '#
21、说明:列出表里的所有的 iu.+bX|b
select name from syscolumns where id=object_id('TableName') rsvGf7C
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。 ,ffH:3F
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 8|p*T&Cn&
显示结果: !xh.S#B
type vender pcs M&O .7B1}
电脑 A 1 GCPSe A~cx
电脑 A 1 VFwp .1oa!
光盘 B 2 Mi"dFx^Md
光盘 A 2 3YPoObY
手机 B 3 [L@ vC>G
手机 C 3 .B9rG~
23、说明:初始化表table1 H<YS2Ed
TRUNCATE TABLE table1 t.oP]_mI
24、说明:选择从10到15的记录 lGr(GHn
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "8Y4;lbN.q
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三、技巧 ,;yiV<AD
1、1=1,1=2的使用,在SQL语句组合时用的较多 5rpTR
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @dCoh-Q3
如: 'Nv*ePz
if @strWhere !='' Am?
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begin \{[Gdj`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Y_49UtJIg
end $k|k 5cP8x
else LCRZ<?O[|
begin ;'r} D!8w/
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' F+!K9( `|
end Ojf.D6nY
我们可以直接写成 n`krK"Ii
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere EnGVp<6R
2、收缩数据库 Wo@0yF@
--重建索引 +Q3i&"QB.
DBCC REINDEX
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DBCC INDEXDEFRAG >>voL DDd
--收缩数据和日志 j\D_Z{m2
DBCC SHRINKDB X
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DBCC SHRINKFILE y pv~F
3、压缩数据库 |Psi?'4
dbcc shrinkdatabase(dbname) I|*w?i*
4、转移数据库给新用户以已存在用户权限 O$
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exec sp_change_users_login 'update_one','newname','oldname' Wi
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go kqfO3{-;{:
5、检查备份集 W4Ey]y"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 1>1&NQ#}
6、修复数据库 )Fh+6
ALTER DATABASE [dvbbs] SET SINGLE_USER 5
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GO db%o3>>e
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]E\o<"#t/
GO tk@
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ALTER DATABASE [dvbbs] SET MULTI_USER SM2QF
GO r(W=1e'
7、日志清除 qcSlY&6+
SET NOCOUNT ON }]ak6'|[
DECLARE @LogicalFileName sysname, YQWGv,47\
@MaxMinutes INT, TzT(aWP"
@NewSize INT 6px(]QU
USE tablename -- 要操作的数据库名 9K`(Ys&
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 WleE$ ,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. X\:;A {
@NewSize = 1 -- 你想设定的日志文件的大小(M) 5G"DgG*<
-- Setup / initialize S:IhJQ4K
DECLARE @OriginalSize int roDE?7x1
SELECT @OriginalSize = size '%.:97
FROM sysfiles _yi`relcq-
WHERE name = @LogicalFileName |'B-^? ;
SELECT 'Original Size of ' + db_name() + ' LOG is ' + WdEVT,jjh
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + mhZ{}~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' kcg{z8cd'r
FROM sysfiles ?6;9r[ p
WHERE name = @LogicalFileName 04`2MNfxG
CREATE TABLE DummyTrans [&e|:1
(DummyColumn char (8000) not null) ,%>]
DECLARE @Counter INT, 4PtRTb0<i3
@StartTime DATETIME, ,Jm2|WKH
@TruncLog VARCHAR(255) TYv'#{
SELECT @StartTime = GETDATE(), ]}t6V]`Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' kjVUG >e>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) a<c]N:1
EXEC (@TruncLog) rucgav
-- Wrap the log if necessary. u^HC1r|%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired LhN?j5XqM
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >|{n";n&
AND (@OriginalSize * 8 /1024) > @NewSize B 2p/
BEGIN -- Outer loop. zSy^vM;6zf
SELECT @Counter = 0 e"7<&%
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) S$~T8_m^U
BEGIN -- update Rcg q7W
INSERT DummyTrans VALUES ('Fill Log') tB S+?N
DELETE DummyTrans /V-uo(n< .
SELECT @Counter = @Counter + 1 yx0wR
END Z3C]n,I
EXEC (@TruncLog) tu5g> qb
END %rE:5)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }W2FF
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _}bs0 kIz
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |/^ KFY"
FROM sysfiles Q]/ZVcoqo
WHERE name = @LogicalFileName w)C/EHF
DROP TABLE DummyTrans {KQ-QKxxS
SET NOCOUNT OFF 7:[u.cd
8、说明:更改某个表 I/2{I
exec sp_changeobjectowner 'tablename','dbo' C{{RU7iqc&
9、存储更改全部表 Dq07Z^#'
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Qy4eDv5
@OldOwner as NVARCHAR(128), VQ}N&H)`
@NewOwner as NVARCHAR(128) \#50;
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AS ?04jkq&
DECLARE @Name as NVARCHAR(128) RSfB9)3D
DECLARE @Owner as NVARCHAR(128) ;$nCQ/ /
DECLARE @OwnerName as NVARCHAR(128) ;H' ,PjU
DECLARE curObject CURSOR FOR 7)RDu,fx
select 'Name' = name, ~ 3!yd0[k
'Owner' = user_name(uid) #%9t-
from sysobjects WswM5RN
where user_name(uid)=@OldOwner LZ=E
order by name $^TxLv
OPEN curObject PF+ F^;C
FETCH NEXT FROM curObject INTO @Name, @Owner 7MbV|gM}
WHILE(@@FETCH_STATUS=0) 3<XP/c";
BEGIN rF^H\U:w
if @Owner=@OldOwner eoj(zY3
begin R|m!*B~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) HfOaJ'+e<
exec sp_changeobjectowner @OwnerName, @NewOwner iv!; gMco
end Wq2Bo*[*
-- select @name,@NewOwner,@OldOwner UuKW`(?^
FETCH NEXT FROM curObject INTO @Name, @Owner *KV^X(/
END #x+7-hi
close curObject E8/Pi>QW
deallocate curObject m$.7) 24
GO W-RqooEv
10、SQL SERVER中直接循环写入数据 ([ jm=[E^
declare @i int v) j3YhY
set @i=1 $RA+StF!]
while @i<30 >qy$W4
begin f8?hEa:js
insert into test (userid) values(@i) l NLa:j
set @i=@i+1 *ZkOZ
end Z!+n/ D-1
小记存储过程中经常用到的本周,本月,本年函数 "8$Muwm
Dateadd(wk,datediff(wk,0,getdate()),-1) :@b=;
Dateadd(wk,datediff(wk,0,getdate()),6) 6Z@?W
Dateadd(mm,datediff(mm,0,getdate()),0) \zJb}NbnT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) m0i,Zw{eM
Dateadd(yy,datediff(yy,0,getdate()),0) ;S9
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 84_Y+_9
上面的SQL代码只是一个时间段 bXz*g`=;
Dateadd(wk,datediff(wk,0,getdate()),-1) /pC60y}O0
Dateadd(wk,datediff(wk,0,getdate()),6) *x/H
就是表示本周时间段. [Mk:Zz%
下面的SQL的条件部分,就是查询时间段在本周范围内的: e>UU/Ks
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) \;+TZ1i_
而在存储过程中 F AQx8P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }vb.>hy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)
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