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。 DFZ@q=ZT
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一、基础 6W3oIt
1、说明:创建数据库 ]Oo!>iTQi
CREATE DATABASE database-name :epB:r
2、说明:删除数据库 xWa[qCr
drop database dbname 0&|M/
3、说明:备份sql server [R8BcO(
--- 创建 备份数据的 device QaEiP n~
USE master A0A|c JP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' W[`ybGR<
--- 开始 备份 (>u1O V
BACKUP DATABASE pubs TO testBack ZBY}Mz$
4、说明:创建新表 L3Y2HZ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) C^'r>0
根据已有的表创建新表: /<[_V/g[t?
A:create table tab_new like tab_old (使用旧表创建新表) ZHeue_~x4
B:create table tab_new as select col1,col2... from tab_old definition only dn])6Xl;i
5、说明:删除新表 0Qeda@J
drop table tabname yp=sL' E
6、说明:增加一个列 h7K,q S
Alter table tabname add column col type x4g6Qze
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。 M Tl
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7、说明:添加主键: Alter table tabname add primary key(col) OPq|4xu
说明:删除主键: Alter table tabname drop primary key(col) ,-EN{ed
8、说明:创建索引:create [unique] index idxname on tabname(col....) Z|UVH
删除索引:drop index idxname *wmkcifF;
注:索引是不可更改的,想更改必须删除重新建。 't8!.k
9、说明:创建视图:create view viewname as select statement k:~UBs\)(
删除视图:drop view viewname /o6ido
10、说明:几个简单的基本的sql语句
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选择:select * from table1 where 范围 b0h\l#6
插入:insert into table1(field1,field2) values(value1,value2) [X@{xF^vBQ
删除:delete from table1 where 范围 U,yZ.1V^:
更新:update table1 set field1=value1 where 范围 }0H<G0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S3U]AH)C
排序:select * from table1 order by field1,field2 [desc] -b+)Dp~$p
总数:select count as totalcount from table1 D1>*ml
求和:select sum(field1) as sumvalue from table1 yRyRH%p)
平均:select avg(field1) as avgvalue from table1 7u^wO<
最大:select max(field1) as maxvalue from table1 AriV4 +
最小:select min(field1) as minvalue from table1 Citumc)E
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11、说明:几个高级查询运算词 |SMigSu r`
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A: UNION 运算符 hF^JSCDz l
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 *1b0IQ$g
B: EXCEPT 运算符 ;XZN0A2
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。 B$JPE7h@[P
C: INTERSECT 运算符 Q2)5A&U\
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 XZ$g~r
注:使用运算词的几个查询结果行必须是一致的。 Dqwd=$2%
12、说明:使用外连接 '#j6ZC/?
A、left outer join: 8aRmHy"9l
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 }mZCQJ#`
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^_G#JJ\@$
B:right outer join: 6z~ [Ay
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。 3ZSU^v
C:full outer join: }*-fh$QJ
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 u}R|q
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二、提升 d^IX(y*$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) v\!Cq+lFML
法一:select * into b from a where 1<>1 Edh9=sxL
法二:select top 0 * into b from a d9e~><bPJ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) j/T@-7^0
insert into b(a, b, c) select d,e,f from b; T=V{3v@zs
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) $[cB6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 p'@z}T?F
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :nnch?J_
4、说明:子查询(表名1:a 表名2:b) (1er?4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) \KpJIHkBRy
5、说明:显示文章、提交人和最后回复时间 <$uDN].T4
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b si]MQ\i+
6、说明:外连接查询(表名1:a 表名2:b) Oa@SyroF=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mpDxJk!
7、说明:在线视图查询(表名1:a ) 8?EKF+.u|
select * from (SELECT a,b,c FROM a) T where t.a > 1; Te)%L*X
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 066\zAPdH
select * from table1 where time between time1 and time2 `+TC@2-?
select a,b,c, from table1 where a not between 数值1 and 数值2 \Z%_dT}
9、说明:in 的使用方法 }Sh@.3*
select * from table1 where a [not] in ('值1','值2','值4','值6') }\N ~%?6D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 xQ?$H?5B<
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) qIzv|Nte
11、说明:四表联查问题: eK3d_bF+
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 ..... 4T)`%Oo<}
12、说明:日程安排提前五分钟提醒 +['1~5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n^G[N-\3
13、说明:一条sql 语句搞定数据库分页 OaN"6Ge#
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 V*%><r
14、说明:前10条记录 1)N#
select top 10 * form table1 where 范围 LG(" <CU
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.) vPy."/[u
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) yMgS0
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 \!>qtFT
(select a from tableA ) except (select a from tableB) except (select a from tableC) ZL!5dT&@W
17、说明:随机取出10条数据 9dp4&&Z+F
select top 10 * from tablename order by newid() 2ss*&BR.
18、说明:随机选择记录 mSFA i
select newid() -=1>t3~\
19、说明:删除重复记录 Jl6biJx
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 11fV|b%
20、说明:列出数据库里所有的表名 pF~aR]Q
select name from sysobjects where type='U' }.=wQ_
21、说明:列出表里的所有的 efbJ2C
select name from syscolumns where id=object_id('TableName') Je'%EJ
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。 li')U
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 =t}m
显示结果: JkLpoe81
type vender pcs eVbT<9k
电脑 A 1 e5n"(s"G*[
电脑 A 1 U?:?NC=1{
光盘 B 2 FB~IO#E8W
光盘 A 2 G)3r[C^[k
手机 B 3 ?FZ)
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手机 C 3 mI^S% HT
23、说明:初始化表table1 e]:(.Wb- 9
TRUNCATE TABLE table1 iNL>TVUM
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ="g9>
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三、技巧 3?&P^{
1、1=1,1=2的使用,在SQL语句组合时用的较多 %~Wr/TOt+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !i{5mc\
如: [RDY(}P%
if @strWhere !='' V)oKsO
begin lb}:!Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [F27i#'I]
end gPpk0LZi
else RS{E|
begin 3XUie;*`
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }?U
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end j#VR>0oC]\
我们可以直接写成 ]e?L,1-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .z,`{-7U
2、收缩数据库 G$lE0_j2{
--重建索引 d8^S~7
DBCC REINDEX fhki!# E8M
DBCC INDEXDEFRAG 91FVe
--收缩数据和日志 Nqj5, 9*c
DBCC SHRINKDB BDi+*8
DBCC SHRINKFILE 2d OUY
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3、压缩数据库 wFL7JwK:G
dbcc shrinkdatabase(dbname) ]#FQde4]5
4、转移数据库给新用户以已存在用户权限 kxY9[#:<fB
exec sp_change_users_login 'update_one','newname','oldname' ;l@Ge`&u
go <+<,$jGC-
5、检查备份集 v +?'/Q%
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' gp^xl>E
6、修复数据库 )Y=ti~?M(
ALTER DATABASE [dvbbs] SET SINGLE_USER }A<fCm7
GO 7"])Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1=jwJv.^/
GO #]wBXzu?
ALTER DATABASE [dvbbs] SET MULTI_USER '"V]>)
GO cMAY8$
7、日志清除 1L_(n
SET NOCOUNT ON h7}P5z0F
DECLARE @LogicalFileName sysname, X/S%0AwZ
@MaxMinutes INT, }~ga86:n0
@NewSize INT n=h!V$X
USE tablename -- 要操作的数据库名 ^QTkre
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zgSv -h+f
@MaxMinutes = 10, -- Limit on time allowed to wrap log. U;U19[]
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7I:<i$)V
-- Setup / initialize ","to
DECLARE @OriginalSize int B}d)e_uLj
SELECT @OriginalSize = size XiyL563gh
FROM sysfiles ,LDdL
WHERE name = @LogicalFileName &WVRh=R
SELECT 'Original Size of ' + db_name() + ' LOG is ' + >% E=l
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *iVv(xXgN
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <TEDs4
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FROM sysfiles @p9YHLxLjQ
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans 0(|36;x
(DummyColumn char (8000) not null) ]Mgxv>zRbs
DECLARE @Counter INT, `n%8y I%
@StartTime DATETIME, v-}D>)M^W
@TruncLog VARCHAR(255) aw1f;&K4
SELECT @StartTime = GETDATE(), kNUNh[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' CN#2-[T
DBCC SHRINKFILE (@LogicalFileName, @NewSize) T'%Rkag>
EXEC (@TruncLog) k=.pcDX
-- Wrap the log if necessary. IU rGJ#}O
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired jbu+>
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 2,'%G\QT
AND (@OriginalSize * 8 /1024) > @NewSize ju/#V}N
BEGIN -- Outer loop. 7p Zd?-6M^
SELECT @Counter = 0 e>_Il']Mb
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]nx5E_j2
BEGIN -- update DcNwtts
INSERT DummyTrans VALUES ('Fill Log') D{iPsH6};5
DELETE DummyTrans wB%;O `Oh
SELECT @Counter = @Counter + 1 ]Cc8[ZC
END m)xz_Plc
EXEC (@TruncLog) A}0u-W
END :>, m$XO
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ap .L=vn
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + BGL-lJrG
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' d>`s+B9K0
FROM sysfiles Jgzg[6
WHERE name = @LogicalFileName h1Q rFPQnu
DROP TABLE DummyTrans 7j{63d`2
SET NOCOUNT OFF gib;> nuBK
8、说明:更改某个表 ne'Y {n(8%
exec sp_changeobjectowner 'tablename','dbo' Jnq}SUev
9、存储更改全部表 .OvH<%g!.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch NAEAvXj
@OldOwner as NVARCHAR(128), -F';1D!l%
@NewOwner as NVARCHAR(128) bBXUD;$
AS 2@$`xPg
DECLARE @Name as NVARCHAR(128) r[kmgPld
DECLARE @Owner as NVARCHAR(128) |6zx
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DECLARE @OwnerName as NVARCHAR(128) Hu7WU;w
DECLARE curObject CURSOR FOR "v5jYz5M
select 'Name' = name, @DCw(.k*
'Owner' = user_name(uid) d?1[xv;
from sysobjects K}Rq<zW
where user_name(uid)=@OldOwner iVf8M$!m
order by name 9':MD0P/M
OPEN curObject #~;:i
FETCH NEXT FROM curObject INTO @Name, @Owner 4[f>kY%[
WHILE(@@FETCH_STATUS=0) }FT8[m<
BEGIN :pg]0X;
if @Owner=@OldOwner `EzC'e
begin {~~'
set @OwnerName = @OldOwner + '.' + rtrim(@Name) iea7*]vW
exec sp_changeobjectowner @OwnerName, @NewOwner `:;fc
end vI+X9C?
-- select @name,@NewOwner,@OldOwner '&Tq/;Ml
FETCH NEXT FROM curObject INTO @Name, @Owner iKe68kx
END #P-T4R
close curObject |C.[eHe&D
deallocate curObject APL #-`XC
GO "| KD$CY
10、SQL SERVER中直接循环写入数据 DzG$\%G2R}
declare @i int \kVi&X=q:
set @i=1 mpDQhD[n
while @i<30 aA&}=lm
begin =F90SyzTy
insert into test (userid) values(@i) g,""j`
set @i=@i+1 =&v&qne9
end ]sV) '-
小记存储过程中经常用到的本周,本月,本年函数 CC{{@
Dateadd(wk,datediff(wk,0,getdate()),-1) [[VB'Rs
Dateadd(wk,datediff(wk,0,getdate()),6) 8/+x1, S%
Dateadd(mm,datediff(mm,0,getdate()),0) aj@<4A=;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) j\@osjUu
Dateadd(yy,datediff(yy,0,getdate()),0) C:<TJ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8YwSaBwO
上面的SQL代码只是一个时间段 X,i^OM_
Dateadd(wk,datediff(wk,0,getdate()),-1) 2sNV09id
Dateadd(wk,datediff(wk,0,getdate()),6) ($*R>*6<x
就是表示本周时间段. tk,Vp3p
下面的SQL的条件部分,就是查询时间段在本周范围内的: \TTt!"aK
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 04QY
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而在存储过程中 &{H LYxh
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) <&p0:S7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) _q 1E4z