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。 *s S7^OZ*
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一、基础 bh3}[O,L
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1、说明:创建数据库 u!
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CREATE DATABASE database-name +i4S^B/8i
2、说明:删除数据库 #fRhG^QKp
drop database dbname 4nXS}bW f
3、说明:备份sql server 3!,XR\`[
--- 创建 备份数据的 device lBgf' b3$
USE master Q(T)s
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' y5RcJM
--- 开始 备份 2} /Z.)^Q
BACKUP DATABASE pubs TO testBack ' n#;~
4、说明:创建新表 uqXvN'Jr
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1<\@i{;xsU
根据已有的表创建新表: M0S}-eXc5
A:create table tab_new like tab_old (使用旧表创建新表) pD eqBO
B:create table tab_new as select col1,col2... from tab_old definition only ZXFM_>y5
5、说明:删除新表 506B=
drop table tabname (XX6M[M8
6、说明:增加一个列 U_wn/wcLS
Alter table tabname add column col type imZi7o
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。 1*Yf[;L
7、说明:添加主键: Alter table tabname add primary key(col) bT|a]b:
说明:删除主键: Alter table tabname drop primary key(col) (es+VI2!&C
8、说明:创建索引:create [unique] index idxname on tabname(col....) +=)<
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删除索引:drop index idxname }f+If{
注:索引是不可更改的,想更改必须删除重新建。 #Ne<=ayS
9、说明:创建视图:create view viewname as select statement G{pfyfF
删除视图:drop view viewname m$NBG w
10、说明:几个简单的基本的sql语句 'u@
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选择:select * from table1 where 范围 <IC=x(T
插入:insert into table1(field1,field2) values(value1,value2) S1E=E5
删除:delete from table1 where 范围 ug.mY= n'
更新:update table1 set field1=value1 where 范围 1y2D]h /'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {Uz@`QO3
排序:select * from table1 order by field1,field2 [desc] 9gZMfP
总数:select count as totalcount from table1 JN .\{ Y
求和:select sum(field1) as sumvalue from table1 /!=uM.
平均:select avg(field1) as avgvalue from table1 TUw^KSa
最大:select max(field1) as maxvalue from table1 u}\F9~W-{
最小:select min(field1) as minvalue from table1 aEo!yea
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11、说明:几个高级查询运算词 j&6,%s-M`a
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A: UNION 运算符 L'BDS*
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 5bYU(]
B: EXCEPT 运算符 &=Gz[1
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 >XcbNZV
C: INTERSECT 运算符 W2D^%;mw
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 GpMKOjVm|
注:使用运算词的几个查询结果行必须是一致的。 o]t6u .L
12、说明:使用外连接 HgvgO\`]
A、left outer join: 0&mo1 k_U
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 @zL)R b%P$
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 !
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B:right outer join: r Lg(J|^
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。 vIF=kKl9,
C:full outer join: Sf);j0G,D
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。 )@09Y_9r
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二、提升 %6+J]U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >@KQ )p' `
法一:select * into b from a where 1<>1 CoDu|M%
法二:select top 0 * into b from a ?&I gD.
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Q&]
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insert into b(a, b, c) select d,e,f from b; M#LQz~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) }S<2({GI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 LZch7Xe3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jJkM:iR
4、说明:子查询(表名1:a 表名2:b) D9zw' RY
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) rlT[tOVAY
5、说明:显示文章、提交人和最后回复时间 XSyCT0f08
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b PVP,2Yq!
6、说明:外连接查询(表名1:a 表名2:b) Fq!12/Nn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F1JSf&8
7、说明:在线视图查询(表名1:a ) %Koc^
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select * from (SELECT a,b,c FROM a) T where t.a > 1; 4:q<<vCJv
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 kMWu%,s4
select * from table1 where time between time1 and time2 3UU]w`At
select a,b,c, from table1 where a not between 数值1 and 数值2 o,[~7N
9、说明:in 的使用方法 #H{<nVvg^
select * from table1 where a [not] in ('值1','值2','值4','值6') 2.ud P
10、说明:两张关联表,删除主表中已经在副表中没有的信息 a% |[m,FvP
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ' @>FtF[Gu
11、说明:四表联查问题: f{xR
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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 ..... LTj;e[
12、说明:日程安排提前五分钟提醒 >y m MQEX`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 U_v{Vs
13、说明:一条sql 语句搞定数据库分页 /+l3
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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 S+3'C
14、说明:前10条记录 %Fig`qX
select top 10 * form table1 where 范围 hLPg=8nJ_
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.) ;
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _P
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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,Y@
(select a from tableA ) except (select a from tableB) except (select a from tableC) +Mc kR
17、说明:随机取出10条数据 -}`ES]
select top 10 * from tablename order by newid() rUEoz |e4a
18、说明:随机选择记录 ^"7tfo8
select newid() TU&6\]yF_
19、说明:删除重复记录 S8*VjG?T\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ("0@_05OH
20、说明:列出数据库里所有的表名 o90SXa&l/
select name from sysobjects where type='U' Qj5~ lX`W
21、说明:列出表里的所有的 }ddwL
select name from syscolumns where id=object_id('TableName') W6ZXb_X
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。 [SgWUP*
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 #qXE[%
显示结果: 4r;!b;3
type vender pcs ZZOBMF7
电脑 A 1 v+U(
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电脑 A 1 Ev* b
光盘 B 2 qIcQPJn!}
光盘 A 2 u.*@lGVW
手机 B 3 OLJb8kO
手机 C 3 #c@Dn.W
23、说明:初始化表table1 Z)EmX=
TRUNCATE TABLE table1 mt3j- Mw
24、说明:选择从10到15的记录 xnmIo?
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Yr@_X
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三、技巧 lS]<~
1、1=1,1=2的使用,在SQL语句组合时用的较多 $3S6{"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, j89|hG)2
如: tRRPNY
if @strWhere !='' LuY`mi
begin ?Y+xuY/t
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ot]eaad
end {[G2{ijRz
else ]vJZ v"ACn
begin O&l(`*P
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *')BP;|V`
end 5QB]2c^
我们可以直接写成 vzJ69%E_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .w/#S-at
2、收缩数据库 .Gq.s t%
--重建索引 Os^ sOOSY
DBCC REINDEX vzK*1R5
DBCC INDEXDEFRAG |7]7~ 6l
--收缩数据和日志 Ou</{l/
DBCC SHRINKDB Nv "R'Pps
DBCC SHRINKFILE `}.K@17
3、压缩数据库 h=SQ]nV{
dbcc shrinkdatabase(dbname) fx %Y(W#5
4、转移数据库给新用户以已存在用户权限 @*q WV*$h
exec sp_change_users_login 'update_one','newname','oldname' i)f3\?,,
go ]'V8{l
5、检查备份集 )tR5JK} AV
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dQ ?4@
6、修复数据库 qKt8sxg
ALTER DATABASE [dvbbs] SET SINGLE_USER V&vU her0
GO /:v+:-lU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (-*NRY3*
GO Q:eIq<erY
ALTER DATABASE [dvbbs] SET MULTI_USER v1<gNb)`
GO `bu3S}m7
7、日志清除 Af1izS3
SET NOCOUNT ON Cnd70tbD )
DECLARE @LogicalFileName sysname, 3Yf%M66t
@MaxMinutes INT, L0uvRge
@NewSize INT xEQ2iCeC
USE tablename -- 要操作的数据库名 'ah|cMRn
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 H
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. EQ`;=I3J9y
@NewSize = 1 -- 你想设定的日志文件的大小(M) HmKvu"3
-- Setup / initialize Yao>F--?
DECLARE @OriginalSize int '<~rV
SELECT @OriginalSize = size w]]`/`
FROM sysfiles d=V4,:=S
WHERE name = @LogicalFileName W[PZQCL}K)
SELECT 'Original Size of ' + db_name() + ' LOG is ' + IF~i*
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :0IxnK(r&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' _'<V<OjVM!
FROM sysfiles g0Qg]F5D~
WHERE name = @LogicalFileName ;KJJK#j
CREATE TABLE DummyTrans kRs[H xI3
(DummyColumn char (8000) not null) ~r;da 9
DECLARE @Counter INT, %y.9S=,v,
@StartTime DATETIME, &;L4Cj$q
@TruncLog VARCHAR(255) }MP2)6
SELECT @StartTime = GETDATE(), FP<RoA?W
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $l-|abLELz
DBCC SHRINKFILE (@LogicalFileName, @NewSize) f gI.q
EXEC (@TruncLog) P`6
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-- Wrap the log if necessary. uXq?Z@af|f
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {`QF(WL
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^Dh j<_
AND (@OriginalSize * 8 /1024) > @NewSize o^dt#
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BEGIN -- Outer loop. `q* 0^}
SELECT @Counter = 0 7iu?Q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) W!q'wrIx(
BEGIN -- update ;e;lPM{+
INSERT DummyTrans VALUES ('Fill Log') fZ$<'(t
DELETE DummyTrans /]%,C
SELECT @Counter = @Counter + 1 u^a\02aV[
END 1Lz`.%k`:
EXEC (@TruncLog) uA=6 HpDB
END #@H{Ypn`
SELECT 'Final Size of ' + db_name() + ' LOG is ' + {%D!~,4Ht
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )?~3fb6^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' +*,rOK`C
FROM sysfiles !+& NG&1
WHERE name = @LogicalFileName h95C4jBE
DROP TABLE DummyTrans H^xrFXg~z
SET NOCOUNT OFF !jY/}M~F1
8、说明:更改某个表 +4\JY"oi
exec sp_changeobjectowner 'tablename','dbo' $de_>
9、存储更改全部表 (Tp+43v
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch :Q2\3
@OldOwner as NVARCHAR(128), 8~RUYsg
@NewOwner as NVARCHAR(128) Dntcv|%u
AS $D5[12X
DECLARE @Name as NVARCHAR(128) Na: M1Uhb
DECLARE @Owner as NVARCHAR(128) G?\o_)IJ
DECLARE @OwnerName as NVARCHAR(128) ;d G.oUk=
DECLARE curObject CURSOR FOR $>v^%E;Y4
select 'Name' = name, q_>DX,A
'Owner' = user_name(uid) &<@{ d
from sysobjects g3n^
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where user_name(uid)=@OldOwner nQK@Uy5Yr
order by name WIO V
OPEN curObject B)
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FETCH NEXT FROM curObject INTO @Name, @Owner 0uzis09
WHILE(@@FETCH_STATUS=0) gJi11^PK
BEGIN =sRd5aMs
if @Owner=@OldOwner qTC`[l
begin E#Ynn6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) i_g="^
exec sp_changeobjectowner @OwnerName, @NewOwner 9 U1)sPH;
end +A
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-- select @name,@NewOwner,@OldOwner #W
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FETCH NEXT FROM curObject INTO @Name, @Owner [UNfft=K3P
END hDmtBdE
close curObject $>'}6?C.
deallocate curObject J x-^WB
GO @A!Ef=R
10、SQL SERVER中直接循环写入数据 q9pBS1Ej
declare @i int #[sC H
set @i=1 pTUsdao^,
while @i<30 1mOZ\L!m*
begin ']$ttfJB
insert into test (userid) values(@i) nhk +9
set @i=@i+1 iJ42` 51
end _jH1Mcq
小记存储过程中经常用到的本周,本月,本年函数 g-mK(kY4p
Dateadd(wk,datediff(wk,0,getdate()),-1) mDipP
Dateadd(wk,datediff(wk,0,getdate()),6) RTA9CR)JP4
Dateadd(mm,datediff(mm,0,getdate()),0) H;*:XLPF
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <<(~'$~,L
Dateadd(yy,datediff(yy,0,getdate()),0) IaE};8a8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Q9K
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上面的SQL代码只是一个时间段 R.A}tV=j#
Dateadd(wk,datediff(wk,0,getdate()),-1) 6BW-AZc
Dateadd(wk,datediff(wk,0,getdate()),6) r d]HoFE
就是表示本周时间段. 6#N1 -@
下面的SQL的条件部分,就是查询时间段在本周范围内的: \ :})R{
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) *bn9j>|iv
而在存储过程中 la)f\Nk
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )[9L|o5D
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =%Ut&6}sQ