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。 D G|v'#
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一、基础 X3~`~J
1、说明:创建数据库 B4 5#-V
CREATE DATABASE database-name Ug384RzHN
2、说明:删除数据库 ?<S fhjU
drop database dbname QMy1!:Z&!
3、说明:备份sql server [7 NO !^
--- 创建 备份数据的 device :98:U~d1
USE master
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' +N'&6z0Wf
--- 开始 备份 Xtloyph
BACKUP DATABASE pubs TO testBack d\zUtcJwC
4、说明:创建新表 `xZ,*G7(*
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |9p0"#4u
根据已有的表创建新表: ^+0>,-)F
A:create table tab_new like tab_old (使用旧表创建新表) ]re}EB\Rs
B:create table tab_new as select col1,col2... from tab_old definition only X4+H8],)
5、说明:删除新表 R&$fWV;'
drop table tabname V(g5Gn?
6、说明:增加一个列 `5"3Cj"M
Alter table tabname add column col type rHuzGSX54
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
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7、说明:添加主键: Alter table tabname add primary key(col) wEN[o18{
说明:删除主键: Alter table tabname drop primary key(col) jfVw{\l
8、说明:创建索引:create [unique] index idxname on tabname(col....) sk*vmxClY
删除索引:drop index idxname i|xz
注:索引是不可更改的,想更改必须删除重新建。 `sgW0Uf
9、说明:创建视图:create view viewname as select statement nwzyL`kF
删除视图:drop view viewname |>1#)cONW
10、说明:几个简单的基本的sql语句 Cs\jPh;"
选择:select * from table1 where 范围 dpX Fx"4A
插入:insert into table1(field1,field2) values(value1,value2) gGN6Yqj0
删除:delete from table1 where 范围 LDYa{w-t
更新:update table1 set field1=value1 where 范围 H/Rzs$pnv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! z:
排序:select * from table1 order by field1,field2 [desc] OmK4
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总数:select count as totalcount from table1 _'<FBlIN
求和:select sum(field1) as sumvalue from table1 e {3%-
平均:select avg(field1) as avgvalue from table1 >&k`NXS|V
最大:select max(field1) as maxvalue from table1 $=`d[04
最小:select min(field1) as minvalue from table1 - P"
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11、说明:几个高级查询运算词 TuaP
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A: UNION 运算符 E}THG=6
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 hztqZ:
B: EXCEPT 运算符 w9mAeGyE
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 [_}8Vv&6
C: INTERSECT 运算符 Rf2mBjJ(z
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 /a9CqK
注:使用运算词的几个查询结果行必须是一致的。 WJ LqH<
12、说明:使用外连接 }%<_>b\
A、left outer join: 9XhH*tBn7(
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 VvT7v]
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F,Ve, 7kh
B:right outer join: Ix<!0!
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 l|iOdKr h
C:full outer join: >yVp1Se
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 0c8_&
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二、提升 -@Urq>^v T
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Qpj[]c5
法一:select * into b from a where 1<>1 [LUqF?K&
法二:select top 0 * into b from a T LF'7ufq
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Le{.B@2-"
insert into b(a, b, c) select d,e,f from b; atmW? Z
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) .:GOKyr(~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 g/\cN(X
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !H<%X~|,
4、说明:子查询(表名1:a 表名2:b) P2|+7D:
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) &FJr?hY%
5、说明:显示文章、提交人和最后回复时间 \=`jo$S
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #K/JU{"
6、说明:外连接查询(表名1:a 表名2:b)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Hl'AnxE
7、说明:在线视图查询(表名1:a ) VE1j2=3+o
select * from (SELECT a,b,c FROM a) T where t.a > 1; cMoJHC,!
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 -t>"s'kv
select * from table1 where time between time1 and time2 ?;.=o?e9
select a,b,c, from table1 where a not between 数值1 and 数值2 @A<~bod
9、说明:in 的使用方法 JfK4|{@
select * from table1 where a [not] in ('值1','值2','值4','值6') (ss,x CF
10、说明:两张关联表,删除主表中已经在副表中没有的信息 *OIBMx#qxn
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ZU;jz[}
11、说明:四表联查问题: F6b;qb6n
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 ..... }qWB=,8HQ
12、说明:日程安排提前五分钟提醒 TJ_6:;4,|_
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Zb|a\z8 ?
13、说明:一条sql 语句搞定数据库分页 {E7STLQ_%
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 qmenj
14、说明:前10条记录 ,A)Z.OWOq
select top 10 * form table1 where 范围 ET 0(/Zz
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.) -YmIRocx
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) jzZ]+'t
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 8OO[Le]1
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 LafBf6wds
select top 10 * from tablename order by newid() 12_7UWZ"
18、说明:随机选择记录 ll- KK`Ka
select newid() 0
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19、说明:删除重复记录 w`3.wALb
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) .+<Ka0
20、说明:列出数据库里所有的表名 eT ]*c?"
select name from sysobjects where type='U' r y@p
21、说明:列出表里的所有的 4\g[&
select name from syscolumns where id=object_id('TableName') ;DVg[#
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。 o;#8=q
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 uJeJ=7,EO
显示结果: OdL/%Zp}
type vender pcs VeZd\Oe
电脑 A 1 +c,
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电脑 A 1 T:9M|mD
光盘 B 2 E*fa&G~s )
光盘 A 2 Kp1 F"!
手机 B 3 q^n
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手机 C 3 *K@O3n
23、说明:初始化表table1 Y6v#0pT
TRUNCATE TABLE table1 {6wXDZxv
24、说明:选择从10到15的记录 (TO<SY3AB
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc W:6#0b"_#
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三、技巧 z"QXPIXPk
1、1=1,1=2的使用,在SQL语句组合时用的较多 yLK %lP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W- nS{v(
如: fwMYEj
if @strWhere !='' Ro<x#Uo
begin qPWf=s7!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere :}/\hz
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end rc~)%M<[2
else ;OD-?bC
begin H\N}0^ea
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >!{8)ti
end w^YXnLLJG
我们可以直接写成 rKdsVW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Wa.!eAe}
2、收缩数据库 JO&RuAq
--重建索引 ~Fl\c-
DBCC REINDEX Bss*-K]
DBCC INDEXDEFRAG
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--收缩数据和日志 `T ^0&#
DBCC SHRINKDB 7!FiPH~kM
DBCC SHRINKFILE TBba3%
3、压缩数据库 Qz%q#4Zb
dbcc shrinkdatabase(dbname) kM=&Tfpj
4、转移数据库给新用户以已存在用户权限 !dcvG9JZ
exec sp_change_users_login 'update_one','newname','oldname' |ITb1O`_P
go @~N"MsF3
5、检查备份集 -f1}N|hy
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;X0uA?
6、修复数据库 ;:ZD<'+N
ALTER DATABASE [dvbbs] SET SINGLE_USER aRI. &3-
GO 99,=dzm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK %W| Sl
GO MPyDG"B *
ALTER DATABASE [dvbbs] SET MULTI_USER C=U4z|Ym
GO 9f5~hBlo
7、日志清除 SkVah:cF-
SET NOCOUNT ON fb^R3wd$ff
DECLARE @LogicalFileName sysname, nA.U'=`
@MaxMinutes INT, )FIFf;r
@NewSize INT &TrL!9FtJ
USE tablename -- 要操作的数据库名 >1]hR)Ip
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 )`\Q/TMl5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. G{Ju2HY
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0Q,Tcj
-- Setup / initialize 7Q~W}`Qv'
DECLARE @OriginalSize int T2)CiR-b
SELECT @OriginalSize = size Uspv^O9_
FROM sysfiles Pc5C*{C
WHERE name = @LogicalFileName T?=]&9Y'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 9Av{>W?
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b E40^e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' bJR\d0Z
FROM sysfiles k]RQ 7e
WHERE name = @LogicalFileName xS+xUi
CREATE TABLE DummyTrans eoQt87VCU
(DummyColumn char (8000) not null) xy$aFPH!-
DECLARE @Counter INT, a\Gd;C ^`
@StartTime DATETIME, Nl%5OBm
@TruncLog VARCHAR(255) 5INw#1~
SELECT @StartTime = GETDATE(), 2bw.mp&v1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' p:{L fQ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o54=^@>O<j
EXEC (@TruncLog) ncOl}\Q9
-- Wrap the log if necessary. ;:J"- p
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) M\7F1\ X
AND (@OriginalSize * 8 /1024) > @NewSize d/$e#8
BEGIN -- Outer loop. ",,.xLI7
SELECT @Counter = 0 Q^l!cL| {
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `022gHYv
BEGIN -- update +u\w4byl
INSERT DummyTrans VALUES ('Fill Log') +ek6}f#
DELETE DummyTrans V|HO*HiB3
SELECT @Counter = @Counter + 1 }NdLd!
END !,5qAGi0
EXEC (@TruncLog) DZb0'+jQ
END *H=h7ESq
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !O'p{dj][
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + AxTFVot
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' o:
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FROM sysfiles bu\(KR$s
WHERE name = @LogicalFileName ^"vmIC.h
DROP TABLE DummyTrans Y( EF )::
SET NOCOUNT OFF F J?]|S.?,
8、说明:更改某个表 8. +f@wv
exec sp_changeobjectowner 'tablename','dbo' Fy$C._C$
9、存储更改全部表 ]; g~)z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch QqBQ[<_
@OldOwner as NVARCHAR(128), C$LRX7Z`o
@NewOwner as NVARCHAR(128) 'X/:TOk{W
AS mY XL
DECLARE @Name as NVARCHAR(128) Ju;^^
DECLARE @Owner as NVARCHAR(128) d& v 7l
DECLARE @OwnerName as NVARCHAR(128) r(wtuD23q
DECLARE curObject CURSOR FOR Zc&pJP+M'U
select 'Name' = name, Dsv2p~
'Owner' = user_name(uid) ^U,C])n
from sysobjects a_b+RMy
where user_name(uid)=@OldOwner ^r7KEeVD
order by name 29|nt1Z
OPEN curObject |N
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FETCH NEXT FROM curObject INTO @Name, @Owner gS]
WHILE(@@FETCH_STATUS=0) ~=oCou`XF
BEGIN =_Z.x&fi
if @Owner=@OldOwner t 0p
begin >Apa^Bp
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [kgCB7.V
exec sp_changeobjectowner @OwnerName, @NewOwner ,MHF
end [<f9EeziB
-- select @name,@NewOwner,@OldOwner $I ,Np)i
FETCH NEXT FROM curObject INTO @Name, @Owner Ze[\y(K!
END Tpkt'|8
close curObject )2Y]A^ Y
deallocate curObject @KZW*-"
GO w^3S6lK
10、SQL SERVER中直接循环写入数据 ozHL'H
declare @i int wp4
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set @i=1 Eb29tq
while @i<30 v6=X]Ji{YA
begin k>!i
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insert into test (userid) values(@i) pB%oFWqK
set @i=@i+1 6KN6SN$
end zd F;!
小记存储过程中经常用到的本周,本月,本年函数 &Fk|"f+
Dateadd(wk,datediff(wk,0,getdate()),-1) X"HVK+
Dateadd(wk,datediff(wk,0,getdate()),6) />>KCmc
Dateadd(mm,datediff(mm,0,getdate()),0) |B^Picu
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Y[>`#RhP
Dateadd(yy,datediff(yy,0,getdate()),0) hW;n^\lF#e
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) mOLz(0
上面的SQL代码只是一个时间段 W}(T5D" 3x
Dateadd(wk,datediff(wk,0,getdate()),-1) =~)rT8+)
Dateadd(wk,datediff(wk,0,getdate()),6) iT{[zLz>1
就是表示本周时间段. I;, n|o
下面的SQL的条件部分,就是查询时间段在本周范围内的: 8S[bt@v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9c{ ~$zJW
而在存储过程中 o{mVXidE
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ^b= ;
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) yRQNmR;Uy