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。 GOY!()F
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一、基础 bSk)GZyH\d
1、说明:创建数据库 !@f!4n.e|I
CREATE DATABASE database-name M~*o =t
2、说明:删除数据库 DP
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drop database dbname wN$u^]
3、说明:备份sql server NU%W9jQYS
--- 创建 备份数据的 device 4u]>$?X1_
USE master %H7H0%qW
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]]V|]}<)m
--- 开始 备份 aq]bF%7
BACKUP DATABASE pubs TO testBack ,M9Hdm
4、说明:创建新表 Y'x+!&H
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ft Rza
根据已有的表创建新表: 9:CM#N~?o
A:create table tab_new like tab_old (使用旧表创建新表) q=/ck
B:create table tab_new as select col1,col2... from tab_old definition only O.'\GM
5、说明:删除新表 b[my5Ol
drop table tabname ka| 8 _C^z
6、说明:增加一个列 @l&>C#K\
Alter table tabname add column col type :cE~\BS&
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。 `j(-y`fo
7、说明:添加主键: Alter table tabname add primary key(col) uVLKR PY
说明:删除主键: Alter table tabname drop primary key(col) LVNJlRK
8、说明:创建索引:create [unique] index idxname on tabname(col....) )uH#+IU
删除索引:drop index idxname Q|nGY:98
注:索引是不可更改的,想更改必须删除重新建。 hv9k9i7@l
9、说明:创建视图:create view viewname as select statement ?&$BQK
删除视图:drop view viewname e/y\P&"eI
10、说明:几个简单的基本的sql语句 y(=$z/
选择:select * from table1 where 范围 E3 aj
插入:insert into table1(field1,field2) values(value1,value2) m 3"|$0C~
删除:delete from table1 where 范围 ??? ;H
更新:update table1 set field1=value1 where 范围 +IbQVU~/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ivP#qM1*;
排序:select * from table1 order by field1,field2 [desc] j#
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总数:select count as totalcount from table1 oTxE]a,
求和:select sum(field1) as sumvalue from table1 e'5sT#T9 l
平均:select avg(field1) as avgvalue from table1 z-;{pPZ
最大:select max(field1) as maxvalue from table1 5VK.Zs\
最小:select min(field1) as minvalue from table1 nB#XQ8Nzx^
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11、说明:几个高级查询运算词 +jGSD@32>
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A: UNION 运算符 >Ef{e6
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。 vFl06N2
B: EXCEPT 运算符 ~Jx0#+z9V
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。 P^& =L&U
C: INTERSECT 运算符 (@;=[5+
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。 gSXidh}^
注:使用运算词的几个查询结果行必须是一致的。 :B5M#D!dO
12、说明:使用外连接 ^U]B&+m
A、left outer join: \[W)[mH_
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。 M%qHf{ B
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 <~-cp61z;
B:right outer join: =.8fES
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。 v0'`K 5M
C:full outer join: "/qm,$
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。 I2<5#|CXpZ
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二、提升 )~H&YINhn
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Zp
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法一:select * into b from a where 1<>1 y:ad%,. C
法二:select top 0 * into b from a ~SR9*<
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >m4Q*a4M
insert into b(a, b, c) select d,e,f from b; /m(v5v7(
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) 5.zv0tJku
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [}Pi $at
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jP"l5
4、说明:子查询(表名1:a 表名2:b) QK@[b3-h1
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Mib<1ZM
5、说明:显示文章、提交人和最后回复时间 {~+o+LV
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b T~-OC0
6、说明:外连接查询(表名1:a 表名2:b) NX9K%J
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c F*j0o
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7、说明:在线视图查询(表名1:a ) (bo-JOOdY(
select * from (SELECT a,b,c FROM a) T where t.a > 1; ylwh_&>2
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 A4hbh$
select * from table1 where time between time1 and time2 Ue2%w/Yo
select a,b,c, from table1 where a not between 数值1 and 数值2 _0E KE
9、说明:in 的使用方法 fsz:A"0H
select * from table1 where a [not] in ('值1','值2','值4','值6') m9 D'yXZ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 IJ#+"(?7,u
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) (hFyp}jkk
11、说明:四表联查问题: *dmS'/
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 ..... RgTrj
12、说明:日程安排提前五分钟提醒 d}--}&r
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @z1pE@7jK
13、说明:一条sql 语句搞定数据库分页 \:D"#s%x
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 F0]xc
14、说明:前10条记录 ]o3K
select top 10 * form table1 where 范围 m*H' Cb
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.) AOscewQ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c@Q&i
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"V;otlC
(select a from tableA ) except (select a from tableB) except (select a from tableC) tv'=xDCp
17、说明:随机取出10条数据 g=L80$1
select top 10 * from tablename order by newid() E)z=85;_p
18、说明:随机选择记录 35/K9l5
select newid() .-4]FGg3
19、说明:删除重复记录 fF]w[lLDv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Y=\:fa
20、说明:列出数据库里所有的表名 p4^&G/'
select name from sysobjects where type='U' 4c9a"v
21、说明:列出表里的所有的 Eu|O<9U\
select name from syscolumns where id=object_id('TableName') S:8 WBY] M
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 +sFpIiJg
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type =>htX(k}
显示结果: #$ooV1E
type vender pcs SI,
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电脑 A 1 rBUWzpE"
电脑 A 1 z=yE- I{
光盘 B 2 i)th] 1K%
光盘 A 2 H7dT6`<~Y
手机 B 3 $(+#$F<eo+
手机 C 3 pj#l s
23、说明:初始化表table1 4=qZ Z>[t
TRUNCATE TABLE table1 4~i?xo=;v
24、说明:选择从10到15的记录 6<mlx'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E4,
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三、技巧 kJK*wq]U6
1、1=1,1=2的使用,在SQL语句组合时用的较多 Wn-'iD+9<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, zEk/15
如: ,{X}C
if @strWhere !='' qT~a`ou:
begin \wF-[']N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W5,&*mo
end qNi`OVh&
else -CLBf'a
begin c<,R,DR
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' aUk]wiwIR9
end 2#oU2si
我们可以直接写成 _F},Wp:Oh
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .t7ME{
2、收缩数据库 s
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--重建索引 o[)*Y`xq<w
DBCC REINDEX 3?e~J"WXC5
DBCC INDEXDEFRAG c8LMvL
--收缩数据和日志 Vw]!Kb7tA
DBCC SHRINKDB n?*r, )'
DBCC SHRINKFILE d9up!
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3、压缩数据库 QJ +Ml
dbcc shrinkdatabase(dbname) 1pAcaJzf
4、转移数据库给新用户以已存在用户权限 \03ZE^H
exec sp_change_users_login 'update_one','newname','oldname' HZqk)sN
go gY!?JZC-0
5、检查备份集 {5]c\_.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 72 ZoN<c
6、修复数据库 h"7~`!"~
ALTER DATABASE [dvbbs] SET SINGLE_USER XK&G `cJ[
GO 4W#DLip9
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK +{0v@6<(02
GO >&ENrvaJ
ALTER DATABASE [dvbbs] SET MULTI_USER 0f#xyS 3
GO ?Wc+
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7、日志清除 [kf6bf@
SET NOCOUNT ON 9yz@hdG
DECLARE @LogicalFileName sysname, %n6NVi_[
@MaxMinutes INT, /@B2-.w
@NewSize INT WK0:3q(P
USE tablename -- 要操作的数据库名 6MNr H
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $0k7W?tu
@MaxMinutes = 10, -- Limit on time allowed to wrap log. lffw
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@NewSize = 1 -- 你想设定的日志文件的大小(M) X;n09 L`CB
-- Setup / initialize 1,P\dGmu
DECLARE @OriginalSize int Y#QXvo%
SELECT @OriginalSize = size }bSDhMV;
FROM sysfiles c
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WHERE name = @LogicalFileName -lrcb/)Gz
SELECT 'Original Size of ' + db_name() + ' LOG is ' + k~F;G=P
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z~F*$jn
FROM sysfiles H:S<O%f
WHERE name = @LogicalFileName ]
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CREATE TABLE DummyTrans 3N5@<:2`
(DummyColumn char (8000) not null) P=PeWX*L<Z
DECLARE @Counter INT, v*OV\h.
@StartTime DATETIME, !_FTy^@c2
@TruncLog VARCHAR(255) cyo[HI?WM
SELECT @StartTime = GETDATE(), XFYa+]B2q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' C^;>HAK|F
DBCC SHRINKFILE (@LogicalFileName, @NewSize) H+Aidsn
EXEC (@TruncLog) 3"juj'
-- Wrap the log if necessary. NeJ->x,
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired W,"Re,`H
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) u=tp80_
AND (@OriginalSize * 8 /1024) > @NewSize aIDv~#l
BEGIN -- Outer loop. sF>O=F-7
SELECT @Counter = 0 4jSYR#Hqp`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) W*%(J$E
BEGIN -- update ]&N>F8.L+
INSERT DummyTrans VALUES ('Fill Log') wX$|(Y}
DELETE DummyTrans Zl>dBc%
SELECT @Counter = @Counter + 1 f >.^7.is
END ,"Fl/AjO
EXEC (@TruncLog) Y'5(exW
END KaX*) P
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Paeq
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + s/.P/g%tA>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N6v?Qzvi
FROM sysfiles cg o
WHERE name = @LogicalFileName &>B"/z
DROP TABLE DummyTrans 8Ihl}aguW
SET NOCOUNT OFF jZC[_p;
8、说明:更改某个表 JEaTDV_
exec sp_changeobjectowner 'tablename','dbo' d14 n>
9、存储更改全部表 G$2@N6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Oxa8u e?
@OldOwner as NVARCHAR(128), >c Lh$;l
@NewOwner as NVARCHAR(128) no W]E}nN
AS |}.}q
DECLARE @Name as NVARCHAR(128) 0ckmHv
DECLARE @Owner as NVARCHAR(128) bkc*it
DECLARE @OwnerName as NVARCHAR(128) C
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DECLARE curObject CURSOR FOR Ctn
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select 'Name' = name, z:$ibk4#h
'Owner' = user_name(uid) 5\=
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from sysobjects 8\^A;5
where user_name(uid)=@OldOwner uT'l.*W6i
order by name )$1>6C\
OPEN curObject JXMH7
FETCH NEXT FROM curObject INTO @Name, @Owner r@m]#4
WHILE(@@FETCH_STATUS=0) L~^5Ez6U
BEGIN E3l*_b0
if @Owner=@OldOwner nJGs ,~"
begin gnjhy1o
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fIl!{pv[
exec sp_changeobjectowner @OwnerName, @NewOwner _Z!@#y@j
end M2N8?Ycv3
-- select @name,@NewOwner,@OldOwner k=[s%O6H
FETCH NEXT FROM curObject INTO @Name, @Owner A= 5Ebu!z
END 3F@P$4!#l
close curObject * m^\&
deallocate curObject Z.u1Dz
GO pA8As
10、SQL SERVER中直接循环写入数据 ];4!0\M
declare @i int &e@)yVLL
set @i=1 ($kw*H{Ah^
while @i<30 {x.0Yh7
begin XC)9aC@s
insert into test (userid) values(@i) ON){d!]uJ
set @i=@i+1 qSB&Q0T
end TKv!wKI
小记存储过程中经常用到的本周,本月,本年函数 <y] 67:"<v
Dateadd(wk,datediff(wk,0,getdate()),-1) 3_Xu3hNH!
Dateadd(wk,datediff(wk,0,getdate()),6) j&oRj6;Ha+
Dateadd(mm,datediff(mm,0,getdate()),0) 4minzrKM\
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Mh4MaLw
Dateadd(yy,datediff(yy,0,getdate()),0) "mf$E|
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ro\oL
上面的SQL代码只是一个时间段 *H/3xPh,*
Dateadd(wk,datediff(wk,0,getdate()),-1) 26rg-?;V^
Dateadd(wk,datediff(wk,0,getdate()),6) UGI<V!
就是表示本周时间段. %g}d}5s
下面的SQL的条件部分,就是查询时间段在本周范围内的: qrYbc~jI7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) LK~aLa5wG
而在存储过程中 #%\0][Xf
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Qk:Lo*!
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Td|u@l4B