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。 ML905n u
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一、基础 kP%hgZ
1、说明:创建数据库 T06(Q[)
CREATE DATABASE database-name Q
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2、说明:删除数据库 (p%|F`
drop database dbname ae sk.
3、说明:备份sql server G^W0!u,@
--- 创建 备份数据的 device .U0Gm_c0
USE master X!Z)V)@J8
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' {oqbV#/&
--- 开始 备份 %42a>piev
BACKUP DATABASE pubs TO testBack r&
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4、说明:创建新表 G(a5@9F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) wu.l-VmGp)
根据已有的表创建新表: [j0[c9.p[
A:create table tab_new like tab_old (使用旧表创建新表) +=8wZ]
B:create table tab_new as select col1,col2... from tab_old definition only T ?[28|
5、说明:删除新表 1 jidBzu<
drop table tabname BI`)P+K2
6、说明:增加一个列 C>+n>bH]L
Alter table tabname add column col type ,~d0R4)
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。 N@c GjpQ
7、说明:添加主键: Alter table tabname add primary key(col) \s*M5oN]]
说明:删除主键: Alter table tabname drop primary key(col) d. vNiq,`
8、说明:创建索引:create [unique] index idxname on tabname(col....) e3;&
删除索引:drop index idxname G*9>TavE
注:索引是不可更改的,想更改必须删除重新建。 }#ZRi}f2VJ
9、说明:创建视图:create view viewname as select statement ]#]Z]9w
删除视图:drop view viewname 3
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10、说明:几个简单的基本的sql语句 $os]$5(
选择:select * from table1 where 范围 ;Sivu-%
插入:insert into table1(field1,field2) values(value1,value2) ,-e}Xw9
删除:delete from table1 where 范围 GGuU(sL*
更新:update table1 set field1=value1 where 范围 py'vD3Q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Z0L($
排序:select * from table1 order by field1,field2 [desc] AabQ)23R2
总数:select count as totalcount from table1 =PRQ3/?5
求和:select sum(field1) as sumvalue from table1 z^QrIl/<c2
平均:select avg(field1) as avgvalue from table1 n?@zp<
最大:select max(field1) as maxvalue from table1 s=n4'`y1
最小:select min(field1) as minvalue from table1 ^w^e~0
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11、说明:几个高级查询运算词 t<Acq07
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A: UNION 运算符 rC-E+%y
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。 oPmz$]_Z
B: EXCEPT 运算符 2&4nf/sE
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。 ;l*%IMB
C: INTERSECT 运算符 +\T8`iCFB
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。 3<^Up1CaZ
注:使用运算词的几个查询结果行必须是一致的。 xQFY/Z
12、说明:使用外连接 f7_(C0d
A、left outer join: k9x[(
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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。 RTc@`m3 M
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 4^W!,@W
B:right outer join: Ku,wI86
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。 dun`/QKV
C:full outer join: u4Nh_x8\Nr
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。
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二、提升 %P0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0&,D&y%
法一:select * into b from a where 1<>1 m%[e_eS
法二:select top 0 * into b from a 1cK'B<5">]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) XH?//.q
insert into b(a, b, c) select d,e,f from b; u}nS dZC
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) %/Wk+r9uu
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 s:tX3X
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. qk<jvha
4、说明:子查询(表名1:a 表名2:b) bSsg`
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) "&2 F
5、说明:显示文章、提交人和最后回复时间 R0RxcBtG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b w#b@6d
6、说明:外连接查询(表名1:a 表名2:b) zQyI4RHG[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c hBX*02p
7、说明:在线视图查询(表名1:a ) QR&e~rks
select * from (SELECT a,b,c FROM a) T where t.a > 1; _^BA;S@
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 ^K<3_D>1>
select * from table1 where time between time1 and time2 "/zgh
select a,b,c, from table1 where a not between 数值1 and 数值2 \78E>(`'
9、说明:in 的使用方法 qYA~Os1e
select * from table1 where a [not] in ('值1','值2','值4','值6') ZHNL~=r}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 |P>7C
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #sw4)*v
11、说明:四表联查问题: T<B}Z11R
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 ..... 4QA~@pBX^{
12、说明:日程安排提前五分钟提醒 a.V5fl0?I@
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s/7Z.\
13、说明:一条sql 语句搞定数据库分页 *tUOTA 3L
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 3>h2W
14、说明:前10条记录 ^bv^&V&IB
select top 10 * form table1 where 范围 q-`&C
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.) SZKYq8ZA)V
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~,}|~
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 M(a%Qk?]/
(select a from tableA ) except (select a from tableB) except (select a from tableC) Vc9rc}
17、说明:随机取出10条数据 %V>%AP
select top 10 * from tablename order by newid() lI?P_2AaS
18、说明:随机选择记录 MZV$YD^S
select newid() x4*
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19、说明:删除重复记录 +.!D>U$)}
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) a$=~1@
20、说明:列出数据库里所有的表名 fbh,V%t7
select name from sysobjects where type='U' NT+.E[J6
21、说明:列出表里的所有的 =^KgNQ
select name from syscolumns where id=object_id('TableName') VL*KBJ
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。 H{Ewj_L
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 X)KCk2Ax
显示结果: /JS_gr@DK
type vender pcs zFjz%:0
电脑 A 1 .P1WY
电脑 A 1 Yj@Sy
光盘 B 2 ^)-[g
光盘 A 2 T`E0_ZU;
手机 B 3 <MbhBIejr
手机 C 3 ,ucRQ&P
23、说明:初始化表table1 ^sf,mM~D
TRUNCATE TABLE table1 (xb2H~WrN
24、说明:选择从10到15的记录 _f^6F<!
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lEHx/#qt9
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三、技巧 TaRPMKk
1、1=1,1=2的使用,在SQL语句组合时用的较多 VW\S>=O99
"where 1=1" 是表示选择全部 "where 1=2"全部不选, b$b;^nly
如:
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if @strWhere !='' [OCjYC`
begin e{E\YEc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ]Kt@F0U<o
end osXEzr(
else Vkg0C*L_
begin q}t]lD
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @:?[R&`
end d^=)n-!T
我们可以直接写成 gF,=rT1:>r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }i8y/CA
2、收缩数据库 #^L&H
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--重建索引 r]!#v{#.
DBCC REINDEX k;^$Pd?t
DBCC INDEXDEFRAG z6R|1L 1
--收缩数据和日志 p-iFe\+
DBCC SHRINKDB NF&Sv
DBCC SHRINKFILE 'V?FeWp
3、压缩数据库 !i torSl
dbcc shrinkdatabase(dbname) DC h
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4、转移数据库给新用户以已存在用户权限 IB;yL/T
exec sp_change_users_login 'update_one','newname','oldname' ye.6tlW
go f]i"tqoI
5、检查备份集 I(*3n"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;<M}ZL@m
6、修复数据库 ],weqs
ALTER DATABASE [dvbbs] SET SINGLE_USER gk|>E[.
GO d3c.lD)L9
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK O]tR~a
GO Q` u#
ALTER DATABASE [dvbbs] SET MULTI_USER "kP,v&n
GO gL_1~"3KGC
7、日志清除 W/,bz",v3
SET NOCOUNT ON RxqNgun@
DECLARE @LogicalFileName sysname,
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@MaxMinutes INT, YD[HBF)~j
@NewSize INT :xr^E]
USE tablename -- 要操作的数据库名 7GO9z<m)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _|u}^MLO
@MaxMinutes = 10, -- Limit on time allowed to wrap log. AJ}FHym_ZQ
@NewSize = 1 -- 你想设定的日志文件的大小(M) Ca'BE#q
-- Setup / initialize 44u)F@)
DECLARE @OriginalSize int Yk|6?e{+)
SELECT @OriginalSize = size sbmtx/%U
FROM sysfiles +bE{g@%@+
WHERE name = @LogicalFileName WJD2(el
SELECT 'Original Size of ' + db_name() + ' LOG is ' + jQV[zcM
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + p9)YRLOh.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' vcFR Td
FROM sysfiles 'd~(=6J
WHERE name = @LogicalFileName VZt%cq
CREATE TABLE DummyTrans qGA|.I9,
(DummyColumn char (8000) not null) e8<}{N0,n
DECLARE @Counter INT, HF*0
@StartTime DATETIME, C7dq=(p&
@TruncLog VARCHAR(255) Q#3}AO
SELECT @StartTime = GETDATE(), sMMOZ'bT
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Aars\
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ',R%Q0Q
EXEC (@TruncLog) s;I
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-- Wrap the log if necessary. "<=4]Z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 59zWB,y(P
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) a=}1`Q
AND (@OriginalSize * 8 /1024) > @NewSize /ugWl99.W
BEGIN -- Outer loop. 8|zavH#P
SELECT @Counter = 0 I$.lFQ%(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) GKFRZWXdT
BEGIN -- update 9 jjeZc'
INSERT DummyTrans VALUES ('Fill Log') w( V%EEk
DELETE DummyTrans $_F_%m"\
SELECT @Counter = @Counter + 1 j;`pAN('
END rci,&>L"
EXEC (@TruncLog)
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END Ga5s9wC
SELECT 'Final Size of ' + db_name() + ' LOG is ' + cjL)M=pIS
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + b\0>uU
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' B2kZ_4rB
FROM sysfiles fx|d"VF[
WHERE name = @LogicalFileName LG:k}z/T
DROP TABLE DummyTrans mI7lv;oN<5
SET NOCOUNT OFF <XLaJ;j
8、说明:更改某个表 d0)]^4HT|y
exec sp_changeobjectowner 'tablename','dbo' ?+.mP]d_
9、存储更改全部表 )!-gT
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^0v3NG6
@OldOwner as NVARCHAR(128), Sesdhuy.@
@NewOwner as NVARCHAR(128) @.7/lRr@bp
AS q7lC}'2fu
DECLARE @Name as NVARCHAR(128) _G'ki.[S7
DECLARE @Owner as NVARCHAR(128) 82@^vX
DECLARE @OwnerName as NVARCHAR(128) QwX81*nx
DECLARE curObject CURSOR FOR Zy+ERaF|]
select 'Name' = name, dXxf{|gk>
'Owner' = user_name(uid) 5@5*}[M
from sysobjects _5rKuL
where user_name(uid)=@OldOwner ,^G+<T6
order by name rhkKK_
OPEN curObject b3%x&H<j
FETCH NEXT FROM curObject INTO @Name, @Owner MZ}0.KmaZ
WHILE(@@FETCH_STATUS=0) T*/I4"
BEGIN , mz;$z6i
if @Owner=@OldOwner h|]cZMGo
begin OpaRQ=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1 |{s8[;8
exec sp_changeobjectowner @OwnerName, @NewOwner ML>M:Ik+
end #;!@Pf
-- select @name,@NewOwner,@OldOwner 32K& IfV
FETCH NEXT FROM curObject INTO @Name, @Owner z"
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END h)Fc<,vwBE
close curObject '/<\X{l8
deallocate curObject "a2|WKpD
GO 4vbGXb}!
10、SQL SERVER中直接循环写入数据 DyqqY$ vH(
declare @i int -]^JaQw
set @i=1 ;+\h$
while @i<30 Y#c439 &
begin MtL<)?HQ
insert into test (userid) values(@i) kS_#8I
set @i=@i+1 8$~oiK%fw
end @ovaOX
小记存储过程中经常用到的本周,本月,本年函数 we_CF*zj
Dateadd(wk,datediff(wk,0,getdate()),-1) ]AA|BeL?|
Dateadd(wk,datediff(wk,0,getdate()),6) !AXLoq$SY
Dateadd(mm,datediff(mm,0,getdate()),0) >0@w"aKn
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;)h?P.]
Dateadd(yy,datediff(yy,0,getdate()),0) QD0x^v8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) KWo Ps%G
上面的SQL代码只是一个时间段 JE}VRMNr
Dateadd(wk,datediff(wk,0,getdate()),-1) 5,,'hAq_
Dateadd(wk,datediff(wk,0,getdate()),6) !@lx|=#
就是表示本周时间段. a!bW^?PcK
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6MM\nIU)/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) BR|0uJ.M
而在存储过程中 ].rKfv:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) j-BNHX
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) JL
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