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。 "R):B~8|H{
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一、基础 J/RUKhs/
1、说明:创建数据库 ~v+&
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CREATE DATABASE database-name \?
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2、说明:删除数据库 m6'YFpf)V
drop database dbname m}F1sRkdQ
3、说明:备份sql server (AR-8
--- 创建 备份数据的 device :
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USE master .;*0odxv
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
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--- 开始 备份 V-J\!CHX
BACKUP DATABASE pubs TO testBack inR8m 4c]P
4、说明:创建新表 zPhNV8k-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3H4p$\;C
根据已有的表创建新表: Cn+TcdHX
A:create table tab_new like tab_old (使用旧表创建新表) ilzR/DJ Ma
B:create table tab_new as select col1,col2... from tab_old definition only e|Lh~sVq
5、说明:删除新表 V3F2Z_VH2
drop table tabname 0/-[k
6、说明:增加一个列 FC vR
Alter table tabname add column col type uXK$5"
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 t{x&|%u
7、说明:添加主键: Alter table tabname add primary key(col) l^"gpO${K
说明:删除主键: Alter table tabname drop primary key(col) i,b>&V/Y$
8、说明:创建索引:create [unique] index idxname on tabname(col....) )RA7Y}e|m
删除索引:drop index idxname ^H&6'A`
注:索引是不可更改的,想更改必须删除重新建。 {e>}.R
9、说明:创建视图:create view viewname as select statement srg#<oH|{c
删除视图:drop view viewname L;grH5K5
10、说明:几个简单的基本的sql语句 [&)9|EV
选择:select * from table1 where 范围 =]etw
插入:insert into table1(field1,field2) values(value1,value2) U'Vz
删除:delete from table1 where 范围 ii{5z;I]X
更新:update table1 set field1=value1 where 范围 +O\6p
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ' 71D:%p
排序:select * from table1 order by field1,field2 [desc] h9SS
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总数:select count as totalcount from table1 3osAWSCEL
求和:select sum(field1) as sumvalue from table1 IvH0sS`F
平均:select avg(field1) as avgvalue from table1 //|9J(B]
最大:select max(field1) as maxvalue from table1 ) ~ C)4
最小:select min(field1) as minvalue from table1 s)_sLt8?
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11、说明:几个高级查询运算词 =}_c=z?UY
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A: UNION 运算符 d4A}BTs1
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。 /AW6XyMD_
B: EXCEPT 运算符 >;0z-;k6
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。 r ZGA9duy
C: INTERSECT 运算符 rP#@*{";
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。 &Sc0l/
注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 eN,m8A`/S
A、left outer join: ka"jv"z
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。 ilpg()
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 a08B8
B:right outer join: S.M< (
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。 }]tSWVb*
C:full outer join: f)N67z6
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。 4!iS"QH?;^
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二、提升 (7-K4j`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) gY;N>Yq,C
法一:select * into b from a where 1<>1 0D0 #*J
法二:select top 0 * into b from a vWzNsWPK"{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) LOe!qt\&
insert into b(a, b, c) select d,e,f from b; vJXd{iQE@C
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) p72+:I
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 V}@c5)(j
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. /sJk[5!z
4、说明:子查询(表名1:a 表名2:b) QDxL y aL
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) G{ F>=z"(l
5、说明:显示文章、提交人和最后回复时间 {TUCa
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b uyAhN
6、说明:外连接查询(表名1:a 表名2:b) EL~s90C
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c A+Z3b:}~
7、说明:在线视图查询(表名1:a ) zCPjuS/~
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select * from (SELECT a,b,c FROM a) T where t.a > 1; nLT]'B]$+
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 b*.)m
select * from table1 where time between time1 and time2 yf_<o
select a,b,c, from table1 where a not between 数值1 and 数值2 0@3g'TGl
9、说明:in 的使用方法 w_A-:S
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select * from table1 where a [not] in ('值1','值2','值4','值6') _FAwW<S4B
10、说明:两张关联表,删除主表中已经在副表中没有的信息 QF-.")Z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ig$5Ui
11、说明:四表联查问题: 1~Pht:,t
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... t"RgEH@
12、说明:日程安排提前五分钟提醒 ho^1T3
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 F
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13、说明:一条sql 语句搞定数据库分页 Q"Q|]f*
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 *4A.R&Vu
14、说明:前10条记录 *7!}[ v_
select top 10 * form table1 where 范围 NW!e@;E+i
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) /R@(yT=t
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oHeo]<Fbv
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 H]@Zp"7
(select a from tableA ) except (select a from tableB) except (select a from tableC) 1Rl`}7Km
17、说明:随机取出10条数据 kv `x
select top 10 * from tablename order by newid() vs6`oW"{#
18、说明:随机选择记录 }yB@?
select newid() mc9$"
19、说明:删除重复记录 3PBg3Y$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) KHF5Nt
20、说明:列出数据库里所有的表名 V @d:n
select name from sysobjects where type='U' ;'p0"\SV
21、说明:列出表里的所有的 S :(1=@
select name from syscolumns where id=object_id('TableName') _)%4NjWKk
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。 x-%nnC6e
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 Z/Mp=273
显示结果: n7{1m$/
type vender pcs A$1pMG~as
电脑 A 1 2hU4g
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电脑 A 1 QRt(?96
光盘 B 2 3OM\R%M
光盘 A 2 ~ RTjcE
手机 B 3 cH2
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手机 C 3
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23、说明:初始化表table1 ZO0_:T#Z
TRUNCATE TABLE table1 ixfkMM,W
24、说明:选择从10到15的记录 qD`')=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (y(V,kXwa8
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三、技巧 ,[cWG)-
1、1=1,1=2的使用,在SQL语句组合时用的较多 uOougSBV,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Kz^aW
如: C ,fIwqOr3
if @strWhere !='' cl)MI,/>
begin Dw.>4bA.
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BDB-OJ
end L6Ynid.k
else V(w[`^I>~
begin IXzad
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' SkPv.H0Id
end EDnmYaa)dZ
我们可以直接写成 z{ymVd0#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere dB_\,%vAd
2、收缩数据库 L;BYPZR
--重建索引 br'~SXl
DBCC REINDEX ^g~-$ t<!
DBCC INDEXDEFRAG -$T5@
--收缩数据和日志 ?*4]LuK6
DBCC SHRINKDB =8tduB
DBCC SHRINKFILE }i/{8OuW
3、压缩数据库 *DG*&Me
dbcc shrinkdatabase(dbname) qqkZbsN
4、转移数据库给新用户以已存在用户权限 dC.uK^FuJ
exec sp_change_users_login 'update_one','newname','oldname' co~TQpy^
go ?m~x%[Vn
5、检查备份集 nLQ X?:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' m{V@Om
6、修复数据库 9k83wACry
ALTER DATABASE [dvbbs] SET SINGLE_USER 2;kab^iv'
GO 071wo7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZS}2(t
GO ly^F?.e-
ALTER DATABASE [dvbbs] SET MULTI_USER lezdJ
GO _L:
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7、日志清除 xt3IR0
SET NOCOUNT ON w$&10
DECLARE @LogicalFileName sysname, x#ouR+<
@MaxMinutes INT, Hq%`DWus\
@NewSize INT Dnd
USE tablename -- 要操作的数据库名 (:hPT-1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 k@wT,?kD
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1F$a
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@NewSize = 1 -- 你想设定的日志文件的大小(M) KUly"B
-- Setup / initialize K
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DECLARE @OriginalSize int >\>HRyt%
SELECT @OriginalSize = size B!8]\D
FROM sysfiles
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WHERE name = @LogicalFileName 6.By)L
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wuh$=fya
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + =-vk}O0C
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ky$<WZs
FROM sysfiles #}B~V3UD
WHERE name = @LogicalFileName N>gv!z[E
CREATE TABLE DummyTrans 9MGA#a
(DummyColumn char (8000) not null) }K&K{ 9}
DECLARE @Counter INT, S:t7U%
@StartTime DATETIME, ]Mtb~^joG
@TruncLog VARCHAR(255) VW'e&v1 .
SELECT @StartTime = GETDATE(), no; Yu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S :oZ&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Tl25t^Y
EXEC (@TruncLog) *emUQ/uvf
-- Wrap the log if necessary. 2o/AH \=2
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .[CXW2k
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :v&GAs6H
AND (@OriginalSize * 8 /1024) > @NewSize c| p
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BEGIN -- Outer loop. m_St"`6 .
SELECT @Counter = 0 1{u;-pg
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6o{anHBB
BEGIN -- update Q<78<#I
INSERT DummyTrans VALUES ('Fill Log') pX!S*(Q{
DELETE DummyTrans OBj.-jL
SELECT @Counter = @Counter + 1 RtF_p
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END /#Ew{RvW'
EXEC (@TruncLog) Oys.8%+ P
END &5zUk++
SELECT 'Final Size of ' + db_name() + ' LOG is ' + =3& WH0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + }F@`A?k
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' SXgpj
FROM sysfiles =D3Y
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WHERE name = @LogicalFileName LkNfcBa_
DROP TABLE DummyTrans xu_Tocvop
SET NOCOUNT OFF k*^.-v
8、说明:更改某个表 czedn_}%Q
exec sp_changeobjectowner 'tablename','dbo' ZtB0:'o;
9、存储更改全部表 A
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5*4P_q(AxD
@OldOwner as NVARCHAR(128), *D`,z3/*
@NewOwner as NVARCHAR(128) ~tz[=3!1H
AS i8A5m@,G
DECLARE @Name as NVARCHAR(128) 8zZR%fZ
DECLARE @Owner as NVARCHAR(128) NO6. qWl
DECLARE @OwnerName as NVARCHAR(128) g,Q!F
DECLARE curObject CURSOR FOR qjTz]'^BpM
select 'Name' = name, Lmj?V1% V
'Owner' = user_name(uid) y.mojx%?a
from sysobjects >.M
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where user_name(uid)=@OldOwner }g(aZ
order by name spFsrB
OPEN curObject I ][8[UZ
FETCH NEXT FROM curObject INTO @Name, @Owner S
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WHILE(@@FETCH_STATUS=0) %s<7|,
BEGIN r;S%BFMJS
if @Owner=@OldOwner 'v\!}6
begin 8/=[mYn`-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @*_#zU#g
exec sp_changeobjectowner @OwnerName, @NewOwner "hQV\|!\
end t F`>.=
-- select @name,@NewOwner,@OldOwner in B}ydk
FETCH NEXT FROM curObject INTO @Name, @Owner d9sgk3K
END yhUc]6`V.H
close curObject u}#rS%SF*
deallocate curObject Ya=QN<
GO `DJIY_{-2
10、SQL SERVER中直接循环写入数据 Zwq
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declare @i int m<OxO\ Mpf
set @i=1 fpoH7Jd V
while @i<30 =U@*adgw
begin ^hbh|Du
insert into test (userid) values(@i) A7:
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set @i=@i+1 c*\^61T
end 3ON]c13
小记存储过程中经常用到的本周,本月,本年函数 u5idH),<
Dateadd(wk,datediff(wk,0,getdate()),-1) 4"7Qz z
Dateadd(wk,datediff(wk,0,getdate()),6) '^P
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Dateadd(mm,datediff(mm,0,getdate()),0) 9Z#37)
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) o AQ92~b
Dateadd(yy,datediff(yy,0,getdate()),0) /=Xen
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ((X"D/F]
上面的SQL代码只是一个时间段 Ro%S_!
Dateadd(wk,datediff(wk,0,getdate()),-1) Ppx*
Dateadd(wk,datediff(wk,0,getdate()),6) W#??fae
就是表示本周时间段. l~f +h?cF
下面的SQL的条件部分,就是查询时间段在本周范围内的: ;1eu8N8
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) EBebyQcon
而在存储过程中 e HOm^.gd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `SIJszqc
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6^
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