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。 /~RY{ c@#L
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一、基础 %DH2]B? 0
1、说明:创建数据库 @ov*Fh
CREATE DATABASE database-name @AM;58.
2、说明:删除数据库 ;
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drop database dbname O~Eju
3、说明:备份sql server z2:^Qg
--- 创建 备份数据的 device +zMWIG
USE master -'ff0l
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' G
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--- 开始 备份 aYc*v5QN3
BACKUP DATABASE pubs TO testBack RJ+i~;-
4、说明:创建新表 @,btQ_'X
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Fo
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根据已有的表创建新表: X.^S@3[
A:create table tab_new like tab_old (使用旧表创建新表) i> }P V
B:create table tab_new as select col1,col2... from tab_old definition only UbDRzum
5、说明:删除新表 $2lrP]`>j.
drop table tabname <7-Qn(m,
6、说明:增加一个列 t.0F
Alter table tabname add column col type ^lADq']
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 xz5V.
7、说明:添加主键: Alter table tabname add primary key(col) XNODDH
说明:删除主键: Alter table tabname drop primary key(col) VHwAO:+-
8、说明:创建索引:create [unique] index idxname on tabname(col....) _`'VOY`o
删除索引:drop index idxname ?4 p\ujc
注:索引是不可更改的,想更改必须删除重新建。 X6hm,0[
9、说明:创建视图:create view viewname as select statement ;Ih:$"$!
删除视图:drop view viewname Q7u/k$qN
10、说明:几个简单的基本的sql语句 i|5.DhK}
选择:select * from table1 where 范围 {p -q&k&R|
插入:insert into table1(field1,field2) values(value1,value2) J@$h'YUF
删除:delete from table1 where 范围 -qv*%O@
更新:update table1 set field1=value1 where 范围 <0R$yB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7Aj
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排序:select * from table1 order by field1,field2 [desc] >/W
总数:select count as totalcount from table1 PHZ+u@AA6@
求和:select sum(field1) as sumvalue from table1 <:(pnw*L
平均:select avg(field1) as avgvalue from table1 0^?:Zds
最大:select max(field1) as maxvalue from table1 U7GgGMw
最小:select min(field1) as minvalue from table1 X9ua&T2(l
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11、说明:几个高级查询运算词 yDmNPk/
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A: UNION 运算符 =~qQ?;on
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。 q6R``
B: EXCEPT 运算符 >ucVrLm,X
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。 K+2sq+3q
C: INTERSECT 运算符 0^l)9zE
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。 7sgK+
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注:使用运算词的几个查询结果行必须是一致的。 wlSl ~A/s
12、说明:使用外连接 zVeQKN9^Z
A、left outer join: $q}zW%
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 =t@8Y`9w
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c v@_^h}h/,=
B:right outer join: AcRrk
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 G3Z>,"w;=
C:full outer join: ?%)G%2
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ;^fGQ]`4
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二、提升 O$
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) \W%Aeg*c
法一:select * into b from a where 1<>1 cOhx
法二:select top 0 * into b from a ,q[aV 6kO
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \&[Jtv *
insert into b(a, b, c) select d,e,f from b; d'bAM{R>
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) 0O@UT1M;v
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 f}1B-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hmijp1u
4、说明:子查询(表名1:a 表名2:b) VR5CRNBJ
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) B4uJT~,7>
5、说明:显示文章、提交人和最后回复时间 ]6)~Sj$ 5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ev%_8CO4e
6、说明:外连接查询(表名1:a 表名2:b) k4@$vxy0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H YA<
7、说明:在线视图查询(表名1:a ) _BC%98:WP
select * from (SELECT a,b,c FROM a) T where t.a > 1; Ln&'5D#
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 )\xDo<@
select * from table1 where time between time1 and time2 >0^oC[ B
select a,b,c, from table1 where a not between 数值1 and 数值2 \:7G1_o
9、说明:in 的使用方法 ~OdE!!
select * from table1 where a [not] in ('值1','值2','值4','值6') -MA/:EB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9V ]{q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Nj p?/r
11、说明:四表联查问题: O1C|{
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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 ..... 2b&&3u8
12、说明:日程安排提前五分钟提醒 9n\b!*x
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 u;@~P
13、说明:一条sql 语句搞定数据库分页 &>jSuvVT
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 M&93TQU-
14、说明:前10条记录 !L|}/u3v
select top 10 * form table1 where 范围 lla ?;^,
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.) LtJl\m.th
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "W"2Y(
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 \ytF@"7
(select a from tableA ) except (select a from tableB) except (select a from tableC) F\K&$5J{p
17、说明:随机取出10条数据 !@.9>"FU
select top 10 * from tablename order by newid() 5*~]=(BE
18、说明:随机选择记录 PN(P$6
select newid() 7{"urs7 T
19、说明:删除重复记录 VLL CdZ%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) pbXh}YJ&
20、说明:列出数据库里所有的表名 )qbjX{GZ7
select name from sysobjects where type='U' -gq,^j5,
21、说明:列出表里的所有的 L
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select name from syscolumns where id=object_id('TableName') [5"F=tT7WP
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。 sYMgi D
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 F"G]afI9+
显示结果: L\GjG&Y5
type vender pcs mi`jY0e2
电脑 A 1 YA?46[:
电脑 A 1 $;k2b4u
光盘 B 2 Oh&k{DWE$
光盘 A 2 6=aXz2.f
手机 B 3 !e<D2><^
手机 C 3 .+.'TY--
23、说明:初始化表table1 8lNkY`P7s
TRUNCATE TABLE table1 /Wx({N'h$
24、说明:选择从10到15的记录 Kw/7X[|'G
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc BQOit.
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三、技巧 `!um)4
1、1=1,1=2的使用,在SQL语句组合时用的较多 i 6DcLE
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ntZl(] l
如: ru>c\X^|
if @strWhere !='' K{vn[}
begin bE6:pGr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W Z_yaG$U
end '0jjoZ:
else Cih~cwE
begin 'xG:v)(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' LBw$K0
end Y}n$s/O:u8
我们可以直接写成 DwNEqHi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S.! n35
2、收缩数据库 W }"n*
--重建索引 ^U8^P]{R|
DBCC REINDEX Mhwuh`v%
DBCC INDEXDEFRAG z, f
--收缩数据和日志 wk@S+Q
DBCC SHRINKDB 23iMG]J&
DBCC SHRINKFILE q+J;^u"E
3、压缩数据库 JtbwY@R
dbcc shrinkdatabase(dbname) <rbzsn"a
4、转移数据库给新用户以已存在用户权限 zF7*T?3b"
exec sp_change_users_login 'update_one','newname','oldname' k^i\<@v
go YqEB%Y~N+
5、检查备份集 >"/Sa_w
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' C25EIIdRb
6、修复数据库 YD@n8?~$$
ALTER DATABASE [dvbbs] SET SINGLE_USER LJ{P93aq`^
GO 7`pK=E}+
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK =[D
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GO QIWfGVc-
ALTER DATABASE [dvbbs] SET MULTI_USER EyK
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GO U=vh_NHj
7、日志清除 G@=H='
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SET NOCOUNT ON NGs@z^&V
DECLARE @LogicalFileName sysname, OH_ m ZA
@MaxMinutes INT, Qw@_.I
@NewSize INT u|Tg*B
USE tablename -- 要操作的数据库名 ZR*Dl.GWY
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 j96\({;k
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ,?KN;~t#vz
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7,IH7l|G
-- Setup / initialize C?h}n4\B^?
DECLARE @OriginalSize int aBblP8)8;K
SELECT @OriginalSize = size XPfheV G
FROM sysfiles ')82a49eA
WHERE name = @LogicalFileName J};=)xLX;
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Fs 95^T
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + d#>iFD+
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (DTXc2)c
FROM sysfiles z <jH{AU
WHERE name = @LogicalFileName lWRRB&8
CREATE TABLE DummyTrans p
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(DummyColumn char (8000) not null) C4.g}q
DECLARE @Counter INT, i[N=.
@StartTime DATETIME, 0<$t9:dq
@TruncLog VARCHAR(255) nf,u'}psdJ
SELECT @StartTime = GETDATE(), #k/NS
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [:"7B&&A
DBCC SHRINKFILE (@LogicalFileName, @NewSize) S uo
EXEC (@TruncLog) 7@u:F?c
-- Wrap the log if necessary. 8Ben}j)H
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =P)H3|AdIm
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "b
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AND (@OriginalSize * 8 /1024) > @NewSize (O`2$~mIM
BEGIN -- Outer loop. 0w9[Z
SELECT @Counter = 0 )oCb9K:km
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) '.5_L8
BEGIN -- update ;UPI%DnE]
INSERT DummyTrans VALUES ('Fill Log') gQ;1SY!
DELETE DummyTrans v$]eCj'
SELECT @Counter = @Counter + 1 5LVzT1j|
END UgC{
EXEC (@TruncLog) wxW\L!@
END (-bLP
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ? f>pKe
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I?~iEO\nh
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' /xh/M@G3
FROM sysfiles aS)Gj?Odf
WHERE name = @LogicalFileName NB#-W4NA
DROP TABLE DummyTrans syB.Z-Cpd
SET NOCOUNT OFF 3?Tk[m1b
8、说明:更改某个表 Dqg~g|(Q<
exec sp_changeobjectowner 'tablename','dbo' M
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9、存储更改全部表 .j l|?o
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch tMOhH
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@OldOwner as NVARCHAR(128), D%,AdR"m
@NewOwner as NVARCHAR(128) fKQq]&~
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AS n~C!PXE
DECLARE @Name as NVARCHAR(128) "qxu9Hg!
DECLARE @Owner as NVARCHAR(128) ;RW024
DECLARE @OwnerName as NVARCHAR(128) |9x H9@^f
DECLARE curObject CURSOR FOR KL^hYjC
select 'Name' = name, U{|WN7Q:A
'Owner' = user_name(uid) o^*k
from sysobjects 79G& 0 P\
where user_name(uid)=@OldOwner Qk#`e
order by name g|V md
OPEN curObject HTw7l]]
FETCH NEXT FROM curObject INTO @Name, @Owner kY.3x#w
WHILE(@@FETCH_STATUS=0) T$vDw|KSVP
BEGIN M_Z(+k{Gy
if @Owner=@OldOwner %D
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begin 8TV
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) ?o883!&v
exec sp_changeobjectowner @OwnerName, @NewOwner t/Y)% N
end xa]e9u%
-- select @name,@NewOwner,@OldOwner s:f%=4-7
FETCH NEXT FROM curObject INTO @Name, @Owner )a0%62
END ;($" _h
close curObject /^^wHW:
deallocate curObject F?*ko,
GO JR^#NefJ
10、SQL SERVER中直接循环写入数据 N2/t
declare @i int Unc_e
set @i=1 `p\@b~GM
while @i<30 *wNO3tP't
begin Di>B:=
insert into test (userid) values(@i) x-Ug(/!^
set @i=@i+1 Kjfpq!NYE
end *fg|HH+i
小记存储过程中经常用到的本周,本月,本年函数 BELxaV,
Dateadd(wk,datediff(wk,0,getdate()),-1) p8_
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Dateadd(wk,datediff(wk,0,getdate()),6) y~-dQ7r
Dateadd(mm,datediff(mm,0,getdate()),0) Yj#4{2A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) C[IY9s:Pf
Dateadd(yy,datediff(yy,0,getdate()),0) w$j!89@)
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) "79"SSfOc
上面的SQL代码只是一个时间段 ML-?#jNa<
Dateadd(wk,datediff(wk,0,getdate()),-1) SU80i`
Dateadd(wk,datediff(wk,0,getdate()),6) dWDM{t\}\
就是表示本周时间段. jc-$l
下面的SQL的条件部分,就是查询时间段在本周范围内的: 8AQ@?\Rc"2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) =lG/A[66
而在存储过程中 {(j1#9+9
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ,[{Z_co
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) b9cY