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。 iZGc'y
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一、基础 tsR\cO~/
1、说明:创建数据库 0V
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CREATE DATABASE database-name /\_`Pkd3m
2、说明:删除数据库 Fy8KZWim
drop database dbname lN*O</L,"
3、说明:备份sql server FR_R"p
--- 创建 备份数据的 device ?B@(W(I
USE master Z8+{ -
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^Fgmwa'
--- 开始 备份 m5r65=E
BACKUP DATABASE pubs TO testBack D
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4、说明:创建新表 B25@6
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vtG_A{l
根据已有的表创建新表: x|n2,3%
A:create table tab_new like tab_old (使用旧表创建新表) BO<I/J~b
B:create table tab_new as select col1,col2... from tab_old definition only eZR{M\Q
5、说明:删除新表 wQJY,|.
drop table tabname UN[rW0*
6、说明:增加一个列 "jly[M}C
Alter table tabname add column col type ae( o:G
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。 H2`aw3
7、说明:添加主键: Alter table tabname add primary key(col) xM}lX(V!w
说明:删除主键: Alter table tabname drop primary key(col) vs;T}'O
8、说明:创建索引:create [unique] index idxname on tabname(col....) |H 0+.f;
删除索引:drop index idxname Bh?K_{e
注:索引是不可更改的,想更改必须删除重新建。 i6M_Gk}
9、说明:创建视图:create view viewname as select statement Au,xIe!t
删除视图:drop view viewname msOk~ZPE6\
10、说明:几个简单的基本的sql语句 OoTMvZP[
选择:select * from table1 where 范围 vBAds
插入:insert into table1(field1,field2) values(value1,value2) XzGPBi
删除:delete from table1 where 范围 2V7x
更新:update table1 set field1=value1 where 范围 `=^;q6f
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8?!=/Sc
排序:select * from table1 order by field1,field2 [desc] oUXu;@l
总数:select count as totalcount from table1 IT]D;
求和:select sum(field1) as sumvalue from table1 bS_fWD-
平均:select avg(field1) as avgvalue from table1 p6u"$)wt
最大:select max(field1) as maxvalue from table1 |&lAt\
最小:select min(field1) as minvalue from table1 9{\eE]0
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11、说明:几个高级查询运算词 F-g(Hk|v
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A: UNION 运算符 9{_D"h}}
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。 )MqF~[k<-
B: EXCEPT 运算符 B]~#+rMK
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。 `G>
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C: INTERSECT 运算符 cN_e0;*Ua
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。 \xJTsdd
注:使用运算词的几个查询结果行必须是一致的。 /Ps}IW
12、说明:使用外连接 ujsJ;\c
A、left outer join: '|Dm\cy
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。 @/i{By^C
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 cLR02
B:right outer join: ;i?Ao:]
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。 ?XO$9J
C:full outer join: z%5i ^P
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 "&Ym(P
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二、提升 ?-[.H^]s~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) \tE2@
法一:select * into b from a where 1<>1 n}X)a-=
法二:select top 0 * into b from a 9^l_\:4
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8&: *<
insert into b(a, b, c) select d,e,f from b; bv,_7UOG
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ?<VahDBS+A
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 f@Mm{3&.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. i2`i5&*
4、说明:子查询(表名1:a 表名2:b) "mr;|$Y
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) i3g;B?54
5、说明:显示文章、提交人和最后回复时间 TWE$@/9 )g
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b M6U/.
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6、说明:外连接查询(表名1:a 表名2:b) os*QWSs
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3lYM(DT
7、说明:在线视图查询(表名1:a ) N}Ozm6Mc
select * from (SELECT a,b,c FROM a) T where t.a > 1; +~mBo+ ,
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 l}B,SkP^
select * from table1 where time between time1 and time2 2ijw g~_@
select a,b,c, from table1 where a not between 数值1 and 数值2 !/O c)Yk
9、说明:in 的使用方法 'zV/4iE=
select * from table1 where a [not] in ('值1','值2','值4','值6') j;@7V4'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 l<0BMw S8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) LQ
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11、说明:四表联查问题: *+TIF"|1
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... fOtin[|}6@
12、说明:日程安排提前五分钟提醒 ~_=ohb{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 >v^Bn|_/
13、说明:一条sql 语句搞定数据库分页 -N+'+
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Z[:fqvXQ
14、说明:前10条记录 s8iJl+Jm
select top 10 * form table1 where 范围
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Un\h[m
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 /Y|oDfv
(select a from tableA ) except (select a from tableB) except (select a from tableC) tkU"/$Vi\
17、说明:随机取出10条数据 QHnk@R!
select top 10 * from tablename order by newid() ?h4-D:!$L
18、说明:随机选择记录 vQCRs!A
select newid() *l:5FTp
19、说明:删除重复记录 u(V4KUk
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) sxcpWSGA^
20、说明:列出数据库里所有的表名 oZ;u>MeZ
select name from sysobjects where type='U' ?z>ZsD
21、说明:列出表里的所有的 1!<k-vt
select name from syscolumns where id=object_id('TableName') }.w@.
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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。 Q-78B'!=
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 7KU/ 1l9$9
显示结果: b489sa
type vender pcs 3Tv;<hF
电脑 A 1 X?5M)MP+I
电脑 A 1 1MV\Jm
光盘 B 2 ilL] pU-
光盘 A 2 A`2l ;MW
手机 B 3 ~9#[\/;"
手机 C 3 9Cbf[\J!bq
23、说明:初始化表table1 o(5Xj$Z
TRUNCATE TABLE table1 P_)h8-!+ $
24、说明:选择从10到15的记录 Ftu~nh}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc g,/gApa
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三、技巧 D/pc)3Ofe
1、1=1,1=2的使用,在SQL语句组合时用的较多 16=tHo8|
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Wi ]Mp7b
如: ]0<T,m Z
if @strWhere !='' sLh9=Kh`
begin BhC.#u/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ++ !BSQ e
end )HWf`;VQ
else @mM'V5_#
begin ek6PMZF:'
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8*yhx
end <wV?B9j
我们可以直接写成 ]F
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ym
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2、收缩数据库 XUeBK/aQ{
--重建索引 g}nlb.b]{m
DBCC REINDEX LO{{3No
DBCC INDEXDEFRAG w7}m
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--收缩数据和日志 ]&%_Fpx
DBCC SHRINKDB C8i6ESmU
DBCC SHRINKFILE 1B+uv0lA
3、压缩数据库 q]+'{Ci@
dbcc shrinkdatabase(dbname) Ru8k2d$B
4、转移数据库给新用户以已存在用户权限 nE+OBdl
exec sp_change_users_login 'update_one','newname','oldname' .T0w2Dv/
go Stqlp<xy
5、检查备份集 "i/ l'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Oi#F
6、修复数据库 xu[6h?u(h8
ALTER DATABASE [dvbbs] SET SINGLE_USER 8/cD7O
GO Y(QLlJ*)/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ia-`x/r*m
GO E'qGK T
ALTER DATABASE [dvbbs] SET MULTI_USER m3zmyw}
GO CC,_I>t
7、日志清除 :^".cs?g
SET NOCOUNT ON luD.3&0n
DECLARE @LogicalFileName sysname, W.b?MPy]
@MaxMinutes INT, b,U"N-6
@NewSize INT ./nq*4=
USE tablename -- 要操作的数据库名
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 %7WQb]y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }nNZp
@NewSize = 1 -- 你想设定的日志文件的大小(M) Kp[ F@A#
-- Setup / initialize Ul#||B .c{
DECLARE @OriginalSize int 6}bUX_!&s
SELECT @OriginalSize = size b
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FROM sysfiles `BA wef
WHERE name = @LogicalFileName f4Aevh:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + uN1(l}z$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1I< <`7'
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' JD1IL` ta;
FROM sysfiles 9AQMB1D*v4
WHERE name = @LogicalFileName LlAMtw"
CREATE TABLE DummyTrans zFVNb
(DummyColumn char (8000) not null) oGz-lO{lt
DECLARE @Counter INT, b?Dhhf
@StartTime DATETIME, =?fxPT[1K
@TruncLog VARCHAR(255) r9[{0y!4
SELECT @StartTime = GETDATE(), #4uuT?!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Sb@:ercC,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) xW92ZuzSH
EXEC (@TruncLog) ?2h)w=dO
-- Wrap the log if necessary. D=*3Xd
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired M(>" e*Pi
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) }T([gc7~
AND (@OriginalSize * 8 /1024) > @NewSize Fljqh8c5
BEGIN -- Outer loop. VNKtJmt
SELECT @Counter = 0 @64PdM!L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 20glz(
BEGIN -- update t#
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INSERT DummyTrans VALUES ('Fill Log') .ET@J`"M
DELETE DummyTrans $kPC"!X\
SELECT @Counter = @Counter + 1 >|h$d:~n
END 8BP.VxX
EXEC (@TruncLog) Ak(_![Q:q\
END >jI(^8?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + \va'>?#o1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ('yBIb\ue
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' MVe:[=VOT|
FROM sysfiles aH6{_eY
WHERE name = @LogicalFileName ]ADj9
DROP TABLE DummyTrans Y![m'q}K
SET NOCOUNT OFF d8l T+MS=
8、说明:更改某个表 $
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exec sp_changeobjectowner 'tablename','dbo' |ymw])L
9、存储更改全部表 k e$g[g
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch b[}f]pB@n
@OldOwner as NVARCHAR(128), 1u4)
@NewOwner as NVARCHAR(128) R%7*
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AS 9a_B
DECLARE @Name as NVARCHAR(128) #
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DECLARE @Owner as NVARCHAR(128) !brXQj8D7
DECLARE @OwnerName as NVARCHAR(128) H(}Jt!/:
DECLARE curObject CURSOR FOR Qoa gy L
select 'Name' = name, 3q +C8_:
'Owner' = user_name(uid) a%R'x]
from sysobjects M6yzqAh
where user_name(uid)=@OldOwner [QC<u1/"K
order by name x4@v$phyH
OPEN curObject d1MY>zq
FETCH NEXT FROM curObject INTO @Name, @Owner Z/#l~.o[
WHILE(@@FETCH_STATUS=0) )a:j_jy
BEGIN _
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if @Owner=@OldOwner R+}x#
begin \^=Wp'5R
set @OwnerName = @OldOwner + '.' + rtrim(@Name) or2BG&W
exec sp_changeobjectowner @OwnerName, @NewOwner X~ca8!Dq
end 6|#+
-- select @name,@NewOwner,@OldOwner f+*wDH
FETCH NEXT FROM curObject INTO @Name, @Owner tl.I:A5L
END $nX4!X
close curObject $F>
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deallocate curObject _," -25a
GO cE}y~2cH
10、SQL SERVER中直接循环写入数据 ]xJ5}/
declare @i int hEG-,
set @i=1 ?9jl8r>
while @i<30 `$V7AqX (
begin V4c$V]7
insert into test (userid) values(@i) cRt[{HE
set @i=@i+1 )"Ef* /+
end Z' cQ<
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小记存储过程中经常用到的本周,本月,本年函数 oSGx7dj+
Dateadd(wk,datediff(wk,0,getdate()),-1) EP!zcp2' C
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) W*D]?hXU;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 0MV^-M
Dateadd(yy,datediff(yy,0,getdate()),0) n%N|?!rB
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) tCkKJ)m
上面的SQL代码只是一个时间段 vn5X]U"
Dateadd(wk,datediff(wk,0,getdate()),-1) HTfHAc?W
Dateadd(wk,datediff(wk,0,getdate()),6) Z^P]-CB|6A
就是表示本周时间段. :wlX`YW+e
下面的SQL的条件部分,就是查询时间段在本周范围内的: v4X\LsOP
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ZHA6BVVT
而在存储过程中 .QwwGm
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 8#NI`s*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qx#k()E.U