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。 \FmKJ\
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一、基础 T/r#H__`
1、说明:创建数据库 q1VH5'p@
CREATE DATABASE database-name Q\Kx"Y3i
2、说明:删除数据库 Gctsp2ndW
drop database dbname .10y0FL4
3、说明:备份sql server L5fuM]G`
--- 创建 备份数据的 device PgM (l3x
USE master m}j:nk
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R*pC.QiB~
--- 开始 备份 1QqHF$S
BACKUP DATABASE pubs TO testBack G'z{b$?/[
4、说明:创建新表 ;az5ZsvN
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) yzsab ^]
根据已有的表创建新表: ?
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A:create table tab_new like tab_old (使用旧表创建新表) qPGuo5^
B:create table tab_new as select col1,col2... from tab_old definition only A=5epsB
5、说明:删除新表 J%C#V}z7E
drop table tabname *>8ce-PV
6、说明:增加一个列 dP2irC%f8
Alter table tabname add column col type rNOES3[~
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。 K*-@Q0"KM{
7、说明:添加主键: Alter table tabname add primary key(col) tiPa6tQ
说明:删除主键: Alter table tabname drop primary key(col) E6B!+s!]
8、说明:创建索引:create [unique] index idxname on tabname(col....) &^&zR(o`
删除索引:drop index idxname Y.#:HRtgW
注:索引是不可更改的,想更改必须删除重新建。 AV8T
9、说明:创建视图:create view viewname as select statement >x1p%^cA;=
删除视图:drop view viewname {XurC}#\
10、说明:几个简单的基本的sql语句 Q _iO(qu
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选择:select * from table1 where 范围 z&8un%Jt
插入:insert into table1(field1,field2) values(value1,value2) fl\aqtF
删除:delete from table1 where 范围 !5@_j,lW(
更新:update table1 set field1=value1 where 范围 B$Z3+$hfF
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ![6EUMx
排序:select * from table1 order by field1,field2 [desc] `?(Bt|<>
总数:select count as totalcount from table1 :G w~7v_
求和:select sum(field1) as sumvalue from table1 EpJ4`{4
平均:select avg(field1) as avgvalue from table1 ,B}I?vN.
最大:select max(field1) as maxvalue from table1 3-n19[zk
最小:select min(field1) as minvalue from table1 zhI#f0c
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11、说明:几个高级查询运算词 2Se?J)MN
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A: UNION 运算符 ppIbjt6r
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。 ^i)hm
B: EXCEPT 运算符 wXjFLg!g?
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。 FbnO/! $8
C: INTERSECT 运算符
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 w9RS)l2FQ
注:使用运算词的几个查询结果行必须是一致的。 @Y,7'0U
12、说明:使用外连接 OYC_;CP
A、left outer join: )py{\r9X
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 h_d +$W5
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 `~UZU@/x
B:right outer join: U_l'3oPJw
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。 OX:O^ (-r,
C:full outer join: 6pOx'u>h+
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。 Il@Y|hK
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二、提升 U!%!m'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ,fIe&zq
法一:select * into b from a where 1<>1 kU-t7'?4
法二:select top 0 * into b from a |]Z:&[D]i
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) IPSF]"}~
insert into b(a, b, c) select d,e,f from b; if;71ZE
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) ./j,Z$|
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 y %$O-q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ik|-L8
4、说明:子查询(表名1:a 表名2:b) Ch()P.n?
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) _qqr5NU
5、说明:显示文章、提交人和最后回复时间 1T_QX9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \k`n[{
6、说明:外连接查询(表名1:a 表名2:b) H`8``#-|@S
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c GsbAlNP
7、说明:在线视图查询(表名1:a ) %S`
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select * from (SELECT a,b,c FROM a) T where t.a > 1; ;g_>
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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 q{2I_[p
select * from table1 where time between time1 and time2 5m=I*.qE
select a,b,c, from table1 where a not between 数值1 and 数值2 ~1m2#>
9、说明:in 的使用方法 Ogt]_
select * from table1 where a [not] in ('值1','值2','值4','值6') -"Y{$/B
10、说明:两张关联表,删除主表中已经在副表中没有的信息 &Lt[WT$
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 3bqC\i^[\m
11、说明:四表联查问题: MF60-VE
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 ..... dLsn\m>
12、说明:日程安排提前五分钟提醒 bk<\ujH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {u!)y?}I-
13、说明:一条sql 语句搞定数据库分页 $I#q
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 2>-S-;i
14、说明:前10条记录 dw~p?[
select top 10 * form table1 where 范围 3Y)PU=
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.) ~A<H9Bw
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ;n=. {[,
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 o]{uc,
(select a from tableA ) except (select a from tableB) except (select a from tableC) \ 6EKgC1
17、说明:随机取出10条数据 $qF0ltUQ
select top 10 * from tablename order by newid() 7f<EoSK
18、说明:随机选择记录 cH<q:OYi
select newid() lT\a2.E
19、说明:删除重复记录 !|2VWI}
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5!C_X5M
20、说明:列出数据库里所有的表名 _8}QlT
select name from sysobjects where type='U' '`Bm'Dd
21、说明:列出表里的所有的 SxyONp.$\
select name from syscolumns where id=object_id('TableName') T{]~07N?
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。 Xd:7"/:r
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 5#3W5z
显示结果: 30PZ{c&Rll
type vender pcs &Gm$:T'~
电脑 A 1 E^_wI>
电脑 A 1 'B83m#HR#
光盘 B 2 3:"]Rn([P
光盘 A 2 EzW)'Zzw~
手机 B 3 H?}[r)|(3i
手机 C 3 t3Z_Dp~\
23、说明:初始化表table1 b1pQ`qt
TRUNCATE TABLE table1 9/ SXs0
24、说明:选择从10到15的记录 VZ>On$hp
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >Sa*`q3J
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三、技巧 }MR1^
1、1=1,1=2的使用,在SQL语句组合时用的较多 )f+U~4G&
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6,1b=2G
如: @L84>3O
if @strWhere !='' _!xD8Di#
begin bf_I9Z3m
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 71#I5*8
end -71dN0hWh
else xy+QbDT
begin eRbGZYrJ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' q,<[hBri-
end qo+N,x9o
我们可以直接写成 R cY>k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere qZ@0]"h
2、收缩数据库 >idBS
--重建索引 VS#wl|b8
DBCC REINDEX |(
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DBCC INDEXDEFRAG {"*VU3%q
--收缩数据和日志 3<|`0pt}
DBCC SHRINKDB v,NHQyk
DBCC SHRINKFILE @Un/c:n
3、压缩数据库 ?:^mBb)T
dbcc shrinkdatabase(dbname) HLQ"?OFlz
4、转移数据库给新用户以已存在用户权限 Nd:R"
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exec sp_change_users_login 'update_one','newname','oldname' `T/~.`R
go ]u-SL md
5、检查备份集 aRj>iQaddx
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3[p_!eoW
6、修复数据库 sKLX [l
ALTER DATABASE [dvbbs] SET SINGLE_USER nGZX7Fx5
GO k'`m97B
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8B!aO/Km
GO lJykyyCY+
ALTER DATABASE [dvbbs] SET MULTI_USER `|1MlRM9
GO KH KS$D
7、日志清除 y;"
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SET NOCOUNT ON $
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DECLARE @LogicalFileName sysname, 9D@$i<D:
@MaxMinutes INT, `T ^G^7&
@NewSize INT WV;=@v
USE tablename -- 要操作的数据库名 '/0#lF
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W:&R~R
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [}nK"4T"Ri
@NewSize = 1 -- 你想设定的日志文件的大小(M) m:tiY
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-- Setup / initialize %/"Oxi^G
DECLARE @OriginalSize int Gtv,Izt
SELECT @OriginalSize = size RR1A65B
FROM sysfiles J}spiVM
WHERE name = @LogicalFileName <Pqv;WI|R
SELECT 'Original Size of ' + db_name() + ' LOG is ' + @54*.q$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + CDMfa&;T
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tury<*
FROM sysfiles 3K/Df#
WHERE name = @LogicalFileName ske@uzAz
CREATE TABLE DummyTrans # jYpVc{]
(DummyColumn char (8000) not null) !Gs} tiMH
DECLARE @Counter INT, 4z7G2
@StartTime DATETIME, Rz%e>)
@TruncLog VARCHAR(255) @}F Awv^f
SELECT @StartTime = GETDATE(), L/}iy}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' xIbMs4'iEx
DBCC SHRINKFILE (@LogicalFileName, @NewSize) k@!r#`j3
EXEC (@TruncLog) 4FeEGySow
-- Wrap the log if necessary. x
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired F
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) KM?1/KZ/~
AND (@OriginalSize * 8 /1024) > @NewSize 9G?ldp8
BEGIN -- Outer loop.
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SELECT @Counter = 0 t
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "vF
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BEGIN -- update 3EFD%9n
INSERT DummyTrans VALUES ('Fill Log') ux2013C_
DELETE DummyTrans Zp`T
SELECT @Counter = @Counter + 1 suJ_nb
END S[M4ukYK
EXEC (@TruncLog) A(6xg)_XQ
END eOO+>%Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + MlO-+}`_+
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + d<p 2/aA
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ;~ 4k7Uz
FROM sysfiles SDJH;c0
WHERE name = @LogicalFileName Pd=,$UQp
DROP TABLE DummyTrans aA*9,
SET NOCOUNT OFF dFW=9ru+MQ
8、说明:更改某个表 |qcD;
exec sp_changeobjectowner 'tablename','dbo' %(m])
9、存储更改全部表 uq7T{7~<
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Os),;W0w4
@OldOwner as NVARCHAR(128), V}8$p8#<@
@NewOwner as NVARCHAR(128) #m. AN
AS JV"NZvjN7d
DECLARE @Name as NVARCHAR(128) IFNWS,:
DECLARE @Owner as NVARCHAR(128) %Tcf6cK"
DECLARE @OwnerName as NVARCHAR(128) ^%bBW6eZ
DECLARE curObject CURSOR FOR >mu)/kl
select 'Name' = name, I?Y d
'Owner' = user_name(uid) 54p tP
from sysobjects %5 </d5.
where user_name(uid)=@OldOwner R|,7d:k
order by name x2wg^$F*oO
OPEN curObject X33v:9=
FETCH NEXT FROM curObject INTO @Name, @Owner N{akg90
WHILE(@@FETCH_STATUS=0) HQVh+ (
BEGIN 7Ur?ep
if @Owner=@OldOwner iv%w!3#
begin ,\ldz(D?+
set @OwnerName = @OldOwner + '.' + rtrim(@Name) w8M2N]&:
exec sp_changeobjectowner @OwnerName, @NewOwner SBKeb|H8
end rnhFqNT:
-- select @name,@NewOwner,@OldOwner Bt~s*{3$8
FETCH NEXT FROM curObject INTO @Name, @Owner ``4wX-y
END +H'\3^C-
close curObject *_hLD5K!
deallocate curObject WO</Q6+
GO 2wpjU&8W!
10、SQL SERVER中直接循环写入数据 W? ,$!]0
declare @i int W|c.l{A5Q
set @i=1 gp
while @i<30 #!#z5DJu
begin "e62/Ejg%
insert into test (userid) values(@i) 9BON.` |_
set @i=@i+1 90:K#nW;
end tm)*2lH6
小记存储过程中经常用到的本周,本月,本年函数 ~t/JCxa
Dateadd(wk,datediff(wk,0,getdate()),-1) tB6k|cPC
Dateadd(wk,datediff(wk,0,getdate()),6) hY;_/!_
Dateadd(mm,datediff(mm,0,getdate()),0) 8[5|_Eh+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) TQ9'76INb
Dateadd(yy,datediff(yy,0,getdate()),0) qc8Ta"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) B4W\
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上面的SQL代码只是一个时间段 2"/yEg*=
Dateadd(wk,datediff(wk,0,getdate()),-1) 7 ^I:=qc72
Dateadd(wk,datediff(wk,0,getdate()),6) ey1Z/|
就是表示本周时间段. 5{l1A(b
下面的SQL的条件部分,就是查询时间段在本周范围内的: :$H!@n*/R
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) k$[{n'\@
而在存储过程中 l8wF0|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S ~|.&0"\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) QlzQ]:dWC