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。 7Zt\G-QV
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一、基础 7[g;|(G0
1、说明:创建数据库 rxj@NwAno
CREATE DATABASE database-name ).C!
2、说明:删除数据库 Wk\@n+Q{]
drop database dbname ^Pd37&B4V
3、说明:备份sql server _}OJPahw
--- 创建 备份数据的 device GQ2PmnV+
USE master hG7S]\N_
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' VONAw3k7!
--- 开始 备份 !y-2#
BACKUP DATABASE pubs TO testBack "F$o!Vk
4、说明:创建新表 [fi'=Cb
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `uh@iD'KI
根据已有的表创建新表: cEc,eq|
A:create table tab_new like tab_old (使用旧表创建新表) F,M"/hnPT
B:create table tab_new as select col1,col2... from tab_old definition only P4j 8`}&/
5、说明:删除新表 W[E3P,XS
drop table tabname xwnoZ&h
6、说明:增加一个列 #we>75l{+R
Alter table tabname add column col type vo
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 t-i6 FS-
7、说明:添加主键: Alter table tabname add primary key(col) +xfW`[.{
说明:删除主键: Alter table tabname drop primary key(col) l (,;wAH
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;{f?? G
删除索引:drop index idxname ZuvPDW%
注:索引是不可更改的,想更改必须删除重新建。 EB5_;
9、说明:创建视图:create view viewname as select statement Hpi%9SAM
删除视图:drop view viewname `n`"g<K)Q
10、说明:几个简单的基本的sql语句 'd#\7J>d
选择:select * from table1 where 范围 ^mueFw}\
插入:insert into table1(field1,field2) values(value1,value2) ;Q=GJ5`B
删除:delete from table1 where 范围 }l(m5
更新:update table1 set field1=value1 where 范围 i9eyrl+!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! u'i%~(:$\)
排序:select * from table1 order by field1,field2 [desc] LkGf|yd_
总数:select count as totalcount from table1 s!ZW'`4!z
求和:select sum(field1) as sumvalue from table1 z8/xGQn
平均:select avg(field1) as avgvalue from table1 wB>S\~i
最大:select max(field1) as maxvalue from table1 <*"pra{3
最小:select min(field1) as minvalue from table1 OR\DTLIl
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11、说明:几个高级查询运算词 -~\.n
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A: UNION 运算符 4b2mtLn_
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。 Mf:M3H%YV+
B: EXCEPT 运算符 pAil]f6
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。 sQ}%7BMK
C: INTERSECT 运算符 <s/<b*T
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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。 d)0LVa(
注:使用运算词的几个查询结果行必须是一致的。 (+UmUx=
12、说明:使用外连接 LR3`=Z9
A、left outer join: 'Z.OF5|eGT
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。 aLKMDiT
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 v0`qMBr1y
B:right outer join: h zZ-$IX X
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 'sRg4?PT
C:full outer join: 3X$Q,
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。 iog #
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二、提升 8Y\OCwO
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Er"R;l]xJ
法一:select * into b from a where 1<>1 LgP> u?]n
法二:select top 0 * into b from a Qq T/1^imS
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kqD*TJA
insert into b(a, b, c) select d,e,f from b; >wKu6-
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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) 0AK?{y U
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 dXiE.Si
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1xO!w+J#
4、说明:子查询(表名1:a 表名2:b) )d}H>Qx=
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) ut4r~~Ar
5、说明:显示文章、提交人和最后回复时间 ]eYd8s+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b L/q]QgCoA
6、说明:外连接查询(表名1:a 表名2:b) ]bTzbu@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c j9URl$T:
7、说明:在线视图查询(表名1:a ) m']9Q3-
select * from (SELECT a,b,c FROM a) T where t.a > 1; EWb(uWC8h
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 N^h|h
select * from table1 where time between time1 and time2 5[,+\
select a,b,c, from table1 where a not between 数值1 and 数值2 0{?:FQ#
9、说明:in 的使用方法 <E>7>ZL
select * from table1 where a [not] in ('值1','值2','值4','值6') q]"2hLq
10、说明:两张关联表,删除主表中已经在副表中没有的信息 F1gt3 ae
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <rX\LwR
11、说明:四表联查问题: =6cyE
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *$i; o3
12、说明:日程安排提前五分钟提醒 HKTeqH_:
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 [x!i*
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13、说明:一条sql 语句搞定数据库分页 ^^7L"je]g
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 euV $2Fg
14、说明:前10条记录 @s%X
select top 10 * form table1 where 范围 <.,RBo
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 4>4V-m\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &|Lh38s@$#
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 {ExII<=6
(select a from tableA ) except (select a from tableB) except (select a from tableC) 9ZDVy7m\i-
17、说明:随机取出10条数据 FZe:co8Mu
select top 10 * from tablename order by newid() UrO=!G k
18、说明:随机选择记录 ePp[m
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select newid() SU%mmwES3
19、说明:删除重复记录 #V.ZdLo(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) PXw|
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20、说明:列出数据库里所有的表名 k"">2#V
select name from sysobjects where type='U' I&L.;~
21、说明:列出表里的所有的 U^%9
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select name from syscolumns where id=object_id('TableName') MV:W@)rg
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。 w4\BD&7V
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 P<%v+O
显示结果: -xJX _6}A
type vender pcs iv:,fkwG
电脑 A 1 tm(v~L%$>]
电脑 A 1 JY{X,?s
光盘 B 2 tg~A}1o`0
光盘 A 2 (y1$MYZQ
手机 B 3 C,o:
手机 C 3 VmN}FMGN
23、说明:初始化表table1 DH5bpg&T
TRUNCATE TABLE table1 b,#`n
24、说明:选择从10到15的记录 JOBz{;:R{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc r5o@+"!
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三、技巧 0 _Q*E3
1、1=1,1=2的使用,在SQL语句组合时用的较多 JXH",""bq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, oZgHSR RL
如: ;0IvF#SJ(.
if @strWhere !='' jcE Msc
begin 'KH
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .iFViVZC
end '%R<"
else ~gP7s_qr{
begin qQ^d9EK'?~
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' tcZa~3.
end &=G)NeT_
我们可以直接写成 Te# ]Cn|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PPEq6}
2、收缩数据库 >-!r9"8@
--重建索引 +A@m9
DBCC REINDEX lbRzx4=\y
DBCC INDEXDEFRAG {$;2HbM(
--收缩数据和日志 @B?FE\
DBCC SHRINKDB 5J
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DBCC SHRINKFILE Ua %UbAt
3、压缩数据库 C>^,*7dS
dbcc shrinkdatabase(dbname) wb
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4、转移数据库给新用户以已存在用户权限 kP@HG<~
exec sp_change_users_login 'update_one','newname','oldname' IXnb]q.
go TN5>" ??"
5、检查备份集 /ip lU
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' H
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6、修复数据库 j1/+\8Y
ALTER DATABASE [dvbbs] SET SINGLE_USER Oukd_Ryf
GO 1Pm4.C)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK V\0E=M*P
GO I!P4(3skAB
ALTER DATABASE [dvbbs] SET MULTI_USER /hL\,x2
GO g0PT8]8
7、日志清除 E, GN| l
SET NOCOUNT ON Qlw>+y-i
DECLARE @LogicalFileName sysname, 9TC)
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@MaxMinutes INT, 58: :h.:
@NewSize INT ~(P&g7u
USE tablename -- 要操作的数据库名 Zae.MO^C!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uQnT[\k?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. H9U.lb
@NewSize = 1 -- 你想设定的日志文件的大小(M) {Ur7#h5
-- Setup / initialize @Gt`Ds9=
DECLARE @OriginalSize int V@[rf<,
SELECT @OriginalSize = size m^<p8KZ
FROM sysfiles :5J_5,?;`
WHERE name = @LogicalFileName uAUp5XP|Z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + S`0NPGn;@[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + dN< ,%}R
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $E\^v^LW
FROM sysfiles >TY6O.]
WHERE name = @LogicalFileName M7rIi\4K4
CREATE TABLE DummyTrans \8e2?(@"k
(DummyColumn char (8000) not null) ?E6^!4=,
DECLARE @Counter INT, /&r|ec5
@StartTime DATETIME, -jB3L:
@TruncLog VARCHAR(255) ziiwxx_
SELECT @StartTime = GETDATE(), "oR@JbdX
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @ &pqt6/t
DBCC SHRINKFILE (@LogicalFileName, @NewSize) -U>y
EXEC (@TruncLog) 7/aOsW"6
-- Wrap the log if necessary. #Y2i*:<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired S(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Or8kp/d
AND (@OriginalSize * 8 /1024) > @NewSize E$A3|rjnoN
BEGIN -- Outer loop. ~Wei|,w'<
SELECT @Counter = 0 /`3#4=5-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) .1#kDM
BEGIN -- update iG#}`
INSERT DummyTrans VALUES ('Fill Log') kJT+
DELETE DummyTrans i7 w(S3a
SELECT @Counter = @Counter + 1 Qs%B'9")
END B2Z_]q$n*
EXEC (@TruncLog) rOcg+5
END MLr-,
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,$N#Us(Wa
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nls
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -_em%o3XC
FROM sysfiles dEp7{jY1O
WHERE name = @LogicalFileName pvF-Y9Xb
DROP TABLE DummyTrans vcv CD7MD
SET NOCOUNT OFF BhkoSkr
8、说明:更改某个表 q9]IIv
exec sp_changeobjectowner 'tablename','dbo' [c~kF+8
9、存储更改全部表 ;SY\U7B\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch aJzLrX
@OldOwner as NVARCHAR(128), cE\>f8 I
@NewOwner as NVARCHAR(128) -DjJ",h( $
AS mV)+qXC
DECLARE @Name as NVARCHAR(128) pr&=n;_ n
DECLARE @Owner as NVARCHAR(128) ]Y`Ib0$
DECLARE @OwnerName as NVARCHAR(128) ]JXKZV8$0
DECLARE curObject CURSOR FOR __Nv0Ru
select 'Name' = name, 69OF_/23
'Owner' = user_name(uid) ac8P\2{"
from sysobjects 2YlH}fnH
where user_name(uid)=@OldOwner j.%K_h?V5
order by name H
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OPEN curObject -1u9t4+`
FETCH NEXT FROM curObject INTO @Name, @Owner .4-,_`T?
WHILE(@@FETCH_STATUS=0) >/=> B7
BEGIN \)/yC74r7(
if @Owner=@OldOwner !5Sd2<N
begin +?dl`!rE
set @OwnerName = @OldOwner + '.' + rtrim(@Name) VUwC-)
exec sp_changeobjectowner @OwnerName, @NewOwner ;+/o?:AH
end gE])!GMM3
-- select @name,@NewOwner,@OldOwner M{mSd2
FETCH NEXT FROM curObject INTO @Name, @Owner =Vw
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END NxA)@9Q
close curObject Bd~1P/
deallocate curObject =d)-Fd2li
GO ._PzYE|m2
10、SQL SERVER中直接循环写入数据 :O= \<t
declare @i int :j^FJ@2_
set @i=1 [eUftr9&0
while @i<30 fo0+dzazY
begin AUe# RP
insert into test (userid) values(@i) ~1L:_Sg*
set @i=@i+1 E3aDDFDH
end 7.g[SBUOG
小记存储过程中经常用到的本周,本月,本年函数 t2BL(yB
Dateadd(wk,datediff(wk,0,getdate()),-1) $?P22"/p
Dateadd(wk,datediff(wk,0,getdate()),6) jE\Sm2G9
Dateadd(mm,datediff(mm,0,getdate()),0) om h{0jA0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) `bjizS'^
Dateadd(yy,datediff(yy,0,getdate()),0) 7 msAhz
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >>{FzR
上面的SQL代码只是一个时间段 %9oYw9H!
Dateadd(wk,datediff(wk,0,getdate()),-1) O1'm@
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Dateadd(wk,datediff(wk,0,getdate()),6) 2lVHZ\G
就是表示本周时间段. 36.N>G,
下面的SQL的条件部分,就是查询时间段在本周范围内的: JW.=T)
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9f+>ix,ek*
而在存储过程中 C3NdE_E
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 'T<iHV&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) }Gyqq6Aeb