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。 tm.60udbo
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一、基础 S,6/X.QBv
1、说明:创建数据库 zgEN2d
CREATE DATABASE database-name 0a{hCx|$J
2、说明:删除数据库 7`J2/(
drop database dbname n'V{
3、说明:备份sql server ~nU9j"$
--- 创建 备份数据的 device c.Sd~k:3
USE master ?[zw5fUDS
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' D1Zy Js#
--- 开始 备份 zu{K"7Bx
BACKUP DATABASE pubs TO testBack M9R'ONYAa
4、说明:创建新表 oio{@#DX`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) w=;>
根据已有的表创建新表: {24>&<p
A:create table tab_new like tab_old (使用旧表创建新表) }W}( k2r
B:create table tab_new as select col1,col2... from tab_old definition only fm-m?=
5、说明:删除新表 4!!PrXE
drop table tabname Zw0KV%7hD
6、说明:增加一个列 ]dNNw`1\V
Alter table tabname add column col type d=^QK{8
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。 ,H+Y1N4W(
7、说明:添加主键: Alter table tabname add primary key(col) U[x$QG6 m!
说明:删除主键: Alter table tabname drop primary key(col) 4%~*}
8、说明:创建索引:create [unique] index idxname on tabname(col....) >4luZnWMI
删除索引:drop index idxname XN Uw
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement Itr4Pr
删除视图:drop view viewname #%nV\ Bl
10、说明:几个简单的基本的sql语句 T,9q~*"
选择:select * from table1 where 范围 S!u8JG1
插入:insert into table1(field1,field2) values(value1,value2) 6WZffB{-TK
删除:delete from table1 where 范围 -V6caVlg
更新:update table1 set field1=value1 where 范围 ca7Y+9<
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! OgIRI8L
排序:select * from table1 order by field1,field2 [desc] %50)?J=zB
总数:select count as totalcount from table1 }Mt)57rU
求和:select sum(field1) as sumvalue from table1 0)d='3S
平均:select avg(field1) as avgvalue from table1 G7" (,L` 5
最大:select max(field1) as maxvalue from table1 stajTN*J
最小:select min(field1) as minvalue from table1 N? Jy
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11、说明:几个高级查询运算词 q`r| DcN~
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A: UNION 运算符 !xck
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Z[*unIk
B: EXCEPT 运算符 lH=|Qu
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 K:'^f? P
C: INTERSECT 运算符 85G-`T
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 (+(@P*c1
注:使用运算词的几个查询结果行必须是一致的。 ?ld&}|W~
12、说明:使用外连接 YT+b{
A、left outer join: a_P|KRl
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 >"!ScYn
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0}e?hbF%U
B:right outer join: /.7RWy`
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Pp!4Ak4TT9
C:full outer join: ZtO$kK%q;
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。 8k-]u3
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二、提升 nX3?7"v
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?lD)J?j
法一:select * into b from a where 1<>1 ;&CLb`<y
法二:select top 0 * into b from a g?"QahHG
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7!cLTq
insert into b(a, b, c) select d,e,f from b; \_,p@r]Q
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) r c[~S
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9qCE{[(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. m_0y ]RfG
4、说明:子查询(表名1:a 表名2:b) .8s-)I
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) gC2}?nq*
5、说明:显示文章、提交人和最后回复时间 8Y`g$2SZ^8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b H@@ 4n%MK
6、说明:外连接查询(表名1:a 表名2:b) \B~g5}=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7u&l]NC?y
7、说明:在线视图查询(表名1:a ) f:+/=MW
select * from (SELECT a,b,c FROM a) T where t.a > 1; uc+{<E3,%
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 *tj(,:!
select * from table1 where time between time1 and time2 I{dy,\p
select a,b,c, from table1 where a not between 数值1 and 数值2 j36YIz$a
9、说明:in 的使用方法 Z}!'fX."
select * from table1 where a [not] in ('值1','值2','值4','值6') GgY8\>u
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #fa,}aj
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ;GG,Z#\m
11、说明:四表联查问题: c|.te]!ds
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 ..... rmA?Xlh\
12、说明:日程安排提前五分钟提醒 d*{Cv2A.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <!RkkU&
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13、说明:一条sql 语句搞定数据库分页 34!.5^T
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 W
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14、说明:前10条记录 yC 1OeO8{
select top 10 * form table1 where 范围 {p1`[R&n#
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.) %dPk,Ylz
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &J2UAmB
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 s9sl*1n1m`
(select a from tableA ) except (select a from tableB) except (select a from tableC) FtyT:=Kpc
17、说明:随机取出10条数据 2LUsqL\m}.
select top 10 * from tablename order by newid() N2s"$Ttq
18、说明:随机选择记录 }UsH#!9.
select newid() %pq.fZI
19、说明:删除重复记录 ^L$`)Ja
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w;ZT-Fti
20、说明:列出数据库里所有的表名 <}[ !k<
select name from sysobjects where type='U' *:TwO=)
21、说明:列出表里的所有的 4!{lySW
select name from syscolumns where id=object_id('TableName') ;iX~3[]
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。 r2\%/9uO
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 r]cq|Nv8:
显示结果: hOk9 y=
type vender pcs ,e'm@d$Q*
电脑 A 1 z[J=WI
电脑 A 1 id9QfJ9t
光盘 B 2 G3TS?u8Q
光盘 A 2 dT'}:2
手机 B 3 *B!Ox}CI.L
手机 C 3 w>f.@luO4
23、说明:初始化表table1 C <:g"F:k
TRUNCATE TABLE table1 9*s8%pL
24、说明:选择从10到15的记录 |
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc y%%VJ}'X!
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三、技巧 K!CVS7
1、1=1,1=2的使用,在SQL语句组合时用的较多 5B:"$vC{=
"where 1=1" 是表示选择全部 "where 1=2"全部不选, QEqYqAGzu|
如: Mu`_^gG
if @strWhere !='' TM6wjHFm
begin 3_
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere p3 5)K5V
end _@>*]g
else j}.gK6Yq*
begin Uzvd*>mv
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' YQ:$m5ai
end j;}-x1R
我们可以直接写成 s:6K'*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere jGo%Aase
2、收缩数据库 ! N2uJ?t
--重建索引 ^}$t(t
DBCC REINDEX >4wigc
DBCC INDEXDEFRAG
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--收缩数据和日志 'Iw`+=iVz
DBCC SHRINKDB p]S'pzh
DBCC SHRINKFILE A<c<!N
3、压缩数据库 i5le0lM
dbcc shrinkdatabase(dbname) JmCHwyUK?
4、转移数据库给新用户以已存在用户权限 =Ks&m4
exec sp_change_users_login 'update_one','newname','oldname' UNb7WN
go Ue Ci{W
5、检查备份集 JzN "o'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .?NfV%vv
6、修复数据库 vT{(7m!Ra
ALTER DATABASE [dvbbs] SET SINGLE_USER p9i7<X2&
GO no-";{c
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6
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GO [7.Num_L
ALTER DATABASE [dvbbs] SET MULTI_USER ek5j;%~g1
GO 4`l$0m@>
7、日志清除 ~\-=q^/!
SET NOCOUNT ON b~fl,(sZp
DECLARE @LogicalFileName sysname, [F*yh9%\
@MaxMinutes INT, ^n~Kr1}nj
@NewSize INT *<cRQfA1
USE tablename -- 要操作的数据库名 BKTTta1mY
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 xS@jV6E~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (^B1Kt!<
@NewSize = 1 -- 你想设定的日志文件的大小(M) prS%lg>
-- Setup / initialize /Hk})o_
DECLARE @OriginalSize int Y{j~;G@Wl
SELECT @OriginalSize = size `/m]K~~
FROM sysfiles hb8oq3*x
WHERE name = @LogicalFileName /[Fk>Vhp
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^3sv2wh^|8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ?pJ2"/K
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ma?uB8o+~
FROM sysfiles Z*3RI5)dx
WHERE name = @LogicalFileName W!ug^2"
CREATE TABLE DummyTrans r:o9:w:
(DummyColumn char (8000) not null) E^n!h06~G
DECLARE @Counter INT, @dK_w'W
@StartTime DATETIME, lW-G]V
@TruncLog VARCHAR(255) A
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SELECT @StartTime = GETDATE(), Hvz;[!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %fld<O
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _gK}Gi?|
EXEC (@TruncLog) ZJbaioc\
-- Wrap the log if necessary. -{*3<2rFK
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ]+ub
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1^NC=IS9z
AND (@OriginalSize * 8 /1024) > @NewSize 6%t6u3
BEGIN -- Outer loop. tpzWi
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SELECT @Counter = 0 g0jfLv
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9mtndTT 5u
BEGIN -- update IG}yGGn
INSERT DummyTrans VALUES ('Fill Log') 4Kj8i
DELETE DummyTrans qYe`</
SELECT @Counter = @Counter + 1 .DwiIr'
END j#c@dze
EXEC (@TruncLog) =\8 x
END )$Ib6tYY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]Y$Wv9S6
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nO`[C=|
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^WWr8-
FROM sysfiles s +S6'g--
WHERE name = @LogicalFileName >9nVR
DROP TABLE DummyTrans of7'?]w
SET NOCOUNT OFF &Pv$nMB$I
8、说明:更改某个表 ^K[xVB(&
exec sp_changeobjectowner 'tablename','dbo' ]Y?ZUSCJ
9、存储更改全部表 D{8B;+
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch C-49u<;,
@OldOwner as NVARCHAR(128), g; R
@NewOwner as NVARCHAR(128) .I{u[
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AS yWc%z6dXC
DECLARE @Name as NVARCHAR(128) 3k_\xQ
DECLARE @Owner as NVARCHAR(128) }u5J<*:bZ
DECLARE @OwnerName as NVARCHAR(128) V/"41
DECLARE curObject CURSOR FOR sg]g;U
select 'Name' = name, z8};(I>)
'Owner' = user_name(uid) mL,{ZL ^
from sysobjects @6b;sv1W
where user_name(uid)=@OldOwner hn/SS
order by name mvtuV`
OPEN curObject I|mxyyf
FETCH NEXT FROM curObject INTO @Name, @Owner =0U"07%}
WHILE(@@FETCH_STATUS=0) {
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BEGIN o{|
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if @Owner=@OldOwner Lhgs|*M
begin -1!s8G
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 69C
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exec sp_changeobjectowner @OwnerName, @NewOwner `,wX&@sN
end E~Y%x/oX
-- select @name,@NewOwner,@OldOwner Y9(BxDP_+Y
FETCH NEXT FROM curObject INTO @Name, @Owner Nk>6:Ho{G
END #+3I$ k
close curObject 5YiBw|Z7 "
deallocate curObject j)O8&[y=
GO yj`xOncE}
10、SQL SERVER中直接循环写入数据 R2[
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declare @i int VzFzVeJ
set @i=1 t== a(e
while @i<30 xJ|Z]m=d
begin 5z:/d `P[
insert into test (userid) values(@i) ]jJ4\O`
set @i=@i+1 %u$dN9cw
end '#8;bU
小记存储过程中经常用到的本周,本月,本年函数 [6Nzz]yy
Dateadd(wk,datediff(wk,0,getdate()),-1) }4I;<%L3`
Dateadd(wk,datediff(wk,0,getdate()),6) CQ%yki
Dateadd(mm,datediff(mm,0,getdate()),0) s!BZrVM%I`
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) P~*v}A
Dateadd(yy,datediff(yy,0,getdate()),0) qS2]|7q?Tc
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1 ^=[k
上面的SQL代码只是一个时间段 g.O? 1bebe
Dateadd(wk,datediff(wk,0,getdate()),-1) 0 :1ldU
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Dateadd(wk,datediff(wk,0,getdate()),6) @sb00ad2q
就是表示本周时间段. 8 K>Ejr
下面的SQL的条件部分,就是查询时间段在本周范围内的: kPZ1OSX
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 15~+Ga4
而在存储过程中 CU(W0D
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vui{["
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) nnO@$T