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。 gO$!_!@LM
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一、基础 vW]BOzK
1、说明:创建数据库 ipU"|{NK
CREATE DATABASE database-name }bB_[+YV`{
2、说明:删除数据库 #m8Oy|Y9`
drop database dbname .(`u'G=
3、说明:备份sql server #p_ ~L4iW
--- 创建 备份数据的 device >!a*wf~]
USE master rH-_L&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' kkd<CEz2IM
--- 开始 备份 xX|-5cM;
BACKUP DATABASE pubs TO testBack 9ykmz (
4、说明:创建新表 sq<y2j1oF
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lJU[9)Q_
根据已有的表创建新表: i$%V)pH~F
A:create table tab_new like tab_old (使用旧表创建新表) ;dPLi4=o
B:create table tab_new as select col1,col2... from tab_old definition only Ay56@_d2
5、说明:删除新表 i<@|+*>M
drop table tabname M4DRG%21
6、说明:增加一个列 L[O+9Yh
Alter table tabname add column col type ~Q6ufTGhpM
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。 C w$y
7、说明:添加主键: Alter table tabname add primary key(col) K-#Rm%J+Wy
说明:删除主键: Alter table tabname drop primary key(col) lI&0
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8、说明:创建索引:create [unique] index idxname on tabname(col....) T1e}WJbFE
删除索引:drop index idxname DrB=
注:索引是不可更改的,想更改必须删除重新建。 &}P62&
9、说明:创建视图:create view viewname as select statement !{ )H
删除视图:drop view viewname !hJKI.XH
10、说明:几个简单的基本的sql语句 ,:;_j<g`e
选择:select * from table1 where 范围 xQ$*K]VP
插入:insert into table1(field1,field2) values(value1,value2) v"bOv"!al
删除:delete from table1 where 范围 yWX:`*GV
更新:update table1 set field1=value1 where 范围 NB,iC
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! W=G[hT5L{
排序:select * from table1 order by field1,field2 [desc] "}ZD-O`!
总数:select count as totalcount from table1 C\fc 4
求和:select sum(field1) as sumvalue from table1 Z7%>O:@z
平均:select avg(field1) as avgvalue from table1 [!DLT6Qk
最大:select max(field1) as maxvalue from table1 F%< 0pi
最小:select min(field1) as minvalue from table1 rV1JJ.I
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11、说明:几个高级查询运算词 rb,&i1
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A: UNION 运算符 M)-+j{<
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。 y]@_DL#J=
B: EXCEPT 运算符 Kh%9Oy
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。 0p~:fm
C: INTERSECT 运算符 o&X!75^G>
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。 Ig S.U
注:使用运算词的几个查询结果行必须是一致的。 am@\$Sa4
12、说明:使用外连接 l tQ:c
A、left outer join: )vo PH)!
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。 JQ0KXS Nr
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 &)`A4bf%
B:right outer join: X hTp'2,]
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。 Ag}>gbz~G
C:full outer join: 7gPkg63
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。 yyBfLPXZ
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二、提升 L2Mcs
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) R$cg\DD
法一:select * into b from a where 1<>1 3hb1^HNT
法二:select top 0 * into b from a \Mt(9jNK
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) PcJ,Y\"[
insert into b(a, b, c) select d,e,f from b; iPI6 _h
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ]<{BDXIGIE
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >Rx^@yQ!+z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. o6oZk0
4、说明:子查询(表名1:a 表名2:b) L?0dZY-"
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) lq+FH&
5、说明:显示文章、提交人和最后回复时间 %6*xnB?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b t0Ec`+)
6、说明:外连接查询(表名1:a 表名2:b) <7u*OYjA
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c J/ <[irC
7、说明:在线视图查询(表名1:a ) He&dVP
select * from (SELECT a,b,c FROM a) T where t.a > 1; Rs5G5W@"A
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 !`Bb[BTf
select * from table1 where time between time1 and time2 t'FY*|xk
select a,b,c, from table1 where a not between 数值1 and 数值2 k\1q Jr
9、说明:in 的使用方法 yO$]9
select * from table1 where a [not] in ('值1','值2','值4','值6') Hz*!c#
10、说明:两张关联表,删除主表中已经在副表中没有的信息 64`V+Hd
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) (<2PhJ|
11、说明:四表联查问题: ?%B%[u
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 ..... H@5:x8
12、说明:日程安排提前五分钟提醒 ADlPdkmym
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^!N _Nx/M
13、说明:一条sql 语句搞定数据库分页 j9%=8Dn.<
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 Sxf<8Px9i
14、说明:前10条记录 El]Rrku
select top 10 * form table1 where 范围 7BdvJ"
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.) [2.pZB
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }-YD_Pm
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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 _T8#36iR
(select a from tableA ) except (select a from tableB) except (select a from tableC) sf7'8+wj>
17、说明:随机取出10条数据 w6v P
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select top 10 * from tablename order by newid() >*{\N^:z
18、说明:随机选择记录 i
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select newid() <~vamim#K
19、说明:删除重复记录 ^|-x mUC
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) }(O
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20、说明:列出数据库里所有的表名 J{\S+O2,*
select name from sysobjects where type='U' :C_\.pA
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') _`*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。 >mi%L3Pk
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 [:TOU^
显示结果: $kvF]|<bu
type vender pcs T&X*[kP
电脑 A 1 OGrp{s
电脑 A 1 P ;PS+S9
光盘 B 2 <eI7xifD
光盘 A 2 _(TavL>l
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手机 B 3 |:L<Ko
手机 C 3 Qte=<Z)
23、说明:初始化表table1 ^SVdaQ{7
TRUNCATE TABLE table1 Iy6"2$%a
24、说明:选择从10到15的记录 9)3ok#pQ/
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #ZeZs 31
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三、技巧 |9{l8`9}_
1、1=1,1=2的使用,在SQL语句组合时用的较多 VfAIx]Fa
"where 1=1" 是表示选择全部 "where 1=2"全部不选, >-c ;
如: J`Q#p%W
if @strWhere !='' cRDjpc]
begin @;"HslU\Q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ]SFB_5Gb
end ,H'O`oV!1E
else .3Jggp
begin (|Y[5O)
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 4Fgy<^94`
end 6~ev5SD;f
我们可以直接写成 Xd!=1::
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #(?EL@5
2、收缩数据库 !6'j
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--重建索引 w(]Q`
DBCC REINDEX #E3Y;
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DBCC INDEXDEFRAG t.v@\[{-
--收缩数据和日志 w3a`G|
DBCC SHRINKDB r%}wPN(?D
DBCC SHRINKFILE ^!3Sz1
3、压缩数据库 u0^GB9q
dbcc shrinkdatabase(dbname) MW &iNioX
4、转移数据库给新用户以已存在用户权限 X8~cWW
exec sp_change_users_login 'update_one','newname','oldname' vq
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go Jk!}z+X'A
5、检查备份集 -4mUGh1dy
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' O~.A}
6、修复数据库 M~t S
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ALTER DATABASE [dvbbs] SET SINGLE_USER 3l0x~
GO BI?M/pIm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK LNmsv U
GO >j{phZ
ALTER DATABASE [dvbbs] SET MULTI_USER we9R4*j
GO Z)Nl\e& M
7、日志清除 2VyLt=mdh
SET NOCOUNT ON sa36=:5x-
DECLARE @LogicalFileName sysname, ]xBQ7Xqf|
@MaxMinutes INT, }Y~o =3-
@NewSize INT {aqceg
USE tablename -- 要操作的数据库名 `PnB<rf:*1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 <\|f;7/
@MaxMinutes = 10, -- Limit on time allowed to wrap log. / Li?;H
@NewSize = 1 -- 你想设定的日志文件的大小(M) 5 5>^H1M
-- Setup / initialize |tC!`.^\
DECLARE @OriginalSize int a*o#,T5A
SELECT @OriginalSize = size @5K/z<p%
FROM sysfiles .-T^S"`d|
WHERE name = @LogicalFileName ABvB1[s#
SELECT 'Original Size of ' + db_name() + ' LOG is ' + w&:"x@ -|
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b/5
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' glbU\K> >
FROM sysfiles % zHsh
WHERE name = @LogicalFileName '\Z54$
CREATE TABLE DummyTrans cd)yj&:?Bt
(DummyColumn char (8000) not null) %Ak"d+OH4
DECLARE @Counter INT, X!V@jo9?
@StartTime DATETIME, SxcNr5F
@TruncLog VARCHAR(255) n,SD JsS^
SELECT @StartTime = GETDATE(), Z6\OkD
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (dv Cejc^p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "l6v[yv
EXEC (@TruncLog) xG@zy4
-- Wrap the log if necessary. [vV]lWOp'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired fmILkXKz
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) jXB<"bw
AND (@OriginalSize * 8 /1024) > @NewSize H@GiHej
BEGIN -- Outer loop. Ufd{.o[{-
SELECT @Counter = 0 6|+I~zJ88
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ;0( |06=
BEGIN -- update *6=2UJcJ
INSERT DummyTrans VALUES ('Fill Log') ,{MA90!
DELETE DummyTrans /MKcS%/H/
SELECT @Counter = @Counter + 1 gF+Uj( d
END !%>p;H%0
EXEC (@TruncLog) PB*mD7"
END /co^swz
SELECT 'Final Size of ' + db_name() + ' LOG is ' + CKeT%3
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + '+LC.l M
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' tYK
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FROM sysfiles ZG+8kt!w
WHERE name = @LogicalFileName }t#uSz^
DROP TABLE DummyTrans FWcE\;%yVg
SET NOCOUNT OFF >/k[6r5
8、说明:更改某个表 c,-3+b
exec sp_changeobjectowner 'tablename','dbo' o Mk6ZzZ,>
9、存储更改全部表 c L}}^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), *J,VvO9
@NewOwner as NVARCHAR(128) T!u&r
AS EUevR/S
DECLARE @Name as NVARCHAR(128) (+lwt
DECLARE @Owner as NVARCHAR(128) ~'k.'O{
DECLARE @OwnerName as NVARCHAR(128) musZCg$
DECLARE curObject CURSOR FOR
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select 'Name' = name, ,\ [R\s
'Owner' = user_name(uid) YMx]i,u'+
from sysobjects f-&4x_5
where user_name(uid)=@OldOwner Q]wM WV
order by name &6V[@gmD
OPEN curObject <XG&f
FETCH NEXT FROM curObject INTO @Name, @Owner E0]B=-
WHILE(@@FETCH_STATUS=0) aGY R:jR$
BEGIN IGqg,OEAp
if @Owner=@OldOwner LldZ"%P
begin _3v6c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }xXUCU<
exec sp_changeobjectowner @OwnerName, @NewOwner |#G.2hMFr
end ]/&qv6D*d
-- select @name,@NewOwner,@OldOwner 5'>DvCp%M
FETCH NEXT FROM curObject INTO @Name, @Owner ,xmmS\
END 5nC#<EE
close curObject |Xz-rgkQ
deallocate curObject %"kF i
GO w@,Yj#_9cx
10、SQL SERVER中直接循环写入数据 ;cKN5#7
declare @i int R"%zmA@o=
set @i=1 NH+?7rf8
while @i<30 L|O[u^
begin x{y}pH "H
insert into test (userid) values(@i) }Fs;sfH
set @i=@i+1 *9Eep~ 6
end
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小记存储过程中经常用到的本周,本月,本年函数 b?S,%
Dateadd(wk,datediff(wk,0,getdate()),-1) OI:G~Wg
Dateadd(wk,datediff(wk,0,getdate()),6) _D<=Yo
Dateadd(mm,datediff(mm,0,getdate()),0) +ZOjbI)
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) tbMf_-g
Dateadd(yy,datediff(yy,0,getdate()),0) ?}p~8{ '
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .yK~FzLs
上面的SQL代码只是一个时间段 84(NylZ
Dateadd(wk,datediff(wk,0,getdate()),-1) =
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Dateadd(wk,datediff(wk,0,getdate()),6) uW4)DT9[5
就是表示本周时间段. 5,Rxc=
下面的SQL的条件部分,就是查询时间段在本周范围内的: NL`}rj
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8x":7 yV&
而在存储过程中 D XFU~J*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]=Im0s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) SLI(;, s