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。 WnD^F>
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一、基础 &|v{#,ymeb
1、说明:创建数据库 PX;Vo~6
CREATE DATABASE database-name 3/X-Cr+d
2、说明:删除数据库 `J72+ RA
drop database dbname wgCvD
3、说明:备份sql server
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--- 创建 备份数据的 device 9YR]+*
USE master =%!e(N'p
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ePf+[pV3
--- 开始 备份 Dc08D4
BACKUP DATABASE pubs TO testBack (+|X<Bl:`
4、说明:创建新表 b,nn&B5@{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) OE_QInb<
根据已有的表创建新表: q`XW5VV{K
A:create table tab_new like tab_old (使用旧表创建新表) 7FAIew\r
B:create table tab_new as select col1,col2... from tab_old definition only l B1#
5、说明:删除新表 p6`Pp"J_tr
drop table tabname z< z*Wz
6、说明:增加一个列 0y)}.'
Alter table tabname add column col type o4$Ott%Wm
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 gfi
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7、说明:添加主键: Alter table tabname add primary key(col) KX!i\NHz
说明:删除主键: Alter table tabname drop primary key(col) 6gXIt9B.h$
8、说明:创建索引:create [unique] index idxname on tabname(col....) 94\t1fE
删除索引:drop index idxname vt//)*(.$
注:索引是不可更改的,想更改必须删除重新建。 ujU=JlJ7dl
9、说明:创建视图:create view viewname as select statement g %f*ofb
删除视图:drop view viewname &J_Z~^
10、说明:几个简单的基本的sql语句 vu=me?m?(
选择:select * from table1 where 范围 _w 5RK(
插入:insert into table1(field1,field2) values(value1,value2) g%ubvu2t]
删除:delete from table1 where 范围 Ab/j(xr=
更新:update table1 set field1=value1 where 范围 W+_ R hJ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {9L 5Q
排序:select * from table1 order by field1,field2 [desc] CdY8#+"
总数:select count as totalcount from table1 ]<1HM"D
求和:select sum(field1) as sumvalue from table1 oizT-8i@N
平均:select avg(field1) as avgvalue from table1 c! @F
最大:select max(field1) as maxvalue from table1 U#bl=%bF
最小:select min(field1) as minvalue from table1 #O"
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11、说明:几个高级查询运算词 S='
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A: UNION 运算符 PocYFhWQ`
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。 qD#VbvRc9+
B: EXCEPT 运算符 bp#:UUO%S
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。 2R]&v;A
C: INTERSECT 运算符 J{`eLmTu
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。 !22yvT.;[
注:使用运算词的几个查询结果行必须是一致的。 SyO79e*t
12、说明:使用外连接 h{k_6ym
A、left outer join: h4/X
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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。 tAjx\7IX
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 b.b@bq$1
B:right outer join: 2jl)mL
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。
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C:full outer join:
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 R[LsE^
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二、提升 h>alGLN>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1G;8MPU
法一:select * into b from a where 1<>1 JWROYED
法二:select top 0 * into b from a XF|WCZUnY%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;#TaZN
insert into b(a, b, c) select d,e,f from b; l?/Y
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) !Vheq3"q/
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 RW_q~bA9
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) 4,G w#@
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) |ETiLR=&
5、说明:显示文章、提交人和最后回复时间 ][d,l\gu+s
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b y:d{jG^
6、说明:外连接查询(表名1:a 表名2:b) ;gMgj$mI
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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7、说明:在线视图查询(表名1:a ) n,j$D62[
select * from (SELECT a,b,c FROM a) T where t.a > 1; [iS,#w`
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 e'2Y1h
select * from table1 where time between time1 and time2 |%1?3Mpn
select a,b,c, from table1 where a not between 数值1 and 数值2 fQ+\;iAU
9、说明:in 的使用方法 {fV}gR2
select * from table1 where a [not] in ('值1','值2','值4','值6') :m'+tGs
10、说明:两张关联表,删除主表中已经在副表中没有的信息 vMla'5|l
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) NOt@M
11、说明:四表联查问题: iWE)<h
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... -Xz&}QA
12、说明:日程安排提前五分钟提醒 5l DFp9
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]XeO0Y
13、说明:一条sql 语句搞定数据库分页 C5W>W4EM
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 b.F^vv"]]
14、说明:前10条记录 :?Y$bX}a
select top 10 * form table1 where 范围 5\Fz!
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.) {_#y z\j
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) hXn3,3f3oZ
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 YE}s
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4 =Gph
17、说明:随机取出10条数据 uS+k^
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select top 10 * from tablename order by newid() J:j<"uPm
18、说明:随机选择记录 F7MzCZvu
select newid() ]XA4;7
19、说明:删除重复记录 ,FZT~?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 06*rWu9P3
20、说明:列出数据库里所有的表名 `zpbnxOL$T
select name from sysobjects where type='U' ^YvB9XN
21、说明:列出表里的所有的 g~S)aU\:,
select name from syscolumns where id=object_id('TableName') %."@Q$lA
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。 N^w'Hw0
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 1tMQqI`N
显示结果: !k&Q 5s:
type vender pcs @}s$]i$|-
电脑 A 1 6rN(_Oi-
电脑 A 1 _:`!DIz~9}
光盘 B 2 CO?Xt+1hR
光盘 A 2 Y+~g\z-]c
手机 B 3 x9W(cKB'S
手机 C 3 /mM2M-
23、说明:初始化表table1 O
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TRUNCATE TABLE table1 }(XdB:C8
24、说明:选择从10到15的记录 kJQ#Wz|z]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j'0r'
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三、技巧 :_kAl? eJ
1、1=1,1=2的使用,在SQL语句组合时用的较多 J;$N{"M
"where 1=1" 是表示选择全部 "where 1=2"全部不选, wsU V;S*X%
如: [5$w=u"j
if @strWhere !='' S8,Z;y
begin sJ
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere wJ<Oo@snm
end h*B|fy4K9U
else !ZRs;UZ>o
begin o>/O++7R a
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' c`*TPqw(B[
end ,m=4@ofX
我们可以直接写成 -fI@])$9J
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere j2l55@
2、收缩数据库 <M]h{BS=
--重建索引 RW$:9~
DBCC REINDEX e`>{$t
DBCC INDEXDEFRAG z*$q8Z&7rg
--收缩数据和日志 ,m<H-gwa
DBCC SHRINKDB dq1:s1
DBCC SHRINKFILE K+=+?~
3、压缩数据库 >wHxmq8F5<
dbcc shrinkdatabase(dbname) (b,[C\RBF
4、转移数据库给新用户以已存在用户权限 W5L iXM
exec sp_change_users_login 'update_one','newname','oldname' $_H`
go mo{MR:>)
5、检查备份集 ._9
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' y! .J
6、修复数据库 Zk8|K'oHx
ALTER DATABASE [dvbbs] SET SINGLE_USER 6]zd.W
GO =qy=-j]
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4_ v]O
GO YwY74w:
ALTER DATABASE [dvbbs] SET MULTI_USER [+m?G4[
GO l7{oi!
7、日志清除 ^ci3F<?Q=
SET NOCOUNT ON 1?*
DECLARE @LogicalFileName sysname, 0[?ny`Y
@MaxMinutes INT, &UCsBqIY
@NewSize INT 7pA/
USE tablename -- 要操作的数据库名 I\~G|B
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 hI?sOR!
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~ 9)"!
@NewSize = 1 -- 你想设定的日志文件的大小(M) fb~=Y$|
-- Setup / initialize p[lNy{u~M
DECLARE @OriginalSize int $;M:TpX
SELECT @OriginalSize = size dz
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FROM sysfiles r0d35
WHERE name = @LogicalFileName ~_IHaw$hg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + RB* J=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x_Jwd^`t!
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' R" )bDy?
FROM sysfiles uEyH2QO
WHERE name = @LogicalFileName gBh;=vOD
CREATE TABLE DummyTrans km^^T_ M/
(DummyColumn char (8000) not null) Ofm%:}LV
DECLARE @Counter INT, n+lOb
@StartTime DATETIME, yme^b
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@TruncLog VARCHAR(255) {!|}=45Z
SELECT @StartTime = GETDATE(), Y HSYu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "8^5>EJWv
DBCC SHRINKFILE (@LogicalFileName, @NewSize) u]u[(K5F
EXEC (@TruncLog) OouPj@r
-- Wrap the log if necessary. [gy*`@w
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T,xPSN2A*
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *_E|@y
AND (@OriginalSize * 8 /1024) > @NewSize cLPkK3O\=
BEGIN -- Outer loop. K7Rpr.p
SELECT @Counter = 0 >9RD_QG7
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {u1V|q
BEGIN -- update aLJ(?8M@
INSERT DummyTrans VALUES ('Fill Log') )ZrS{vY
DELETE DummyTrans :=%0Mb:
SELECT @Counter = @Counter + 1 o?1;<gs
END Xc"&0v%;#
EXEC (@TruncLog) [aI]y=v
END lrfv+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + X#3et'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + uVzFsgBp
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' >5s6u`\
FROM sysfiles OpM(j&
WHERE name = @LogicalFileName OGl$W>w1
DROP TABLE DummyTrans yaq'Lt`
SET NOCOUNT OFF A)%A!
8、说明:更改某个表 [,2|Flf
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exec sp_changeobjectowner 'tablename','dbo' { hln?'
9、存储更改全部表 &Ysosy*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch lds-T
@OldOwner as NVARCHAR(128), 8-y{a.,u.
@NewOwner as NVARCHAR(128) x(<(t:?o
AS %IC73?
DECLARE @Name as NVARCHAR(128) =+t^ f
DECLARE @Owner as NVARCHAR(128) s"Pf+aTW
DECLARE @OwnerName as NVARCHAR(128) n,B,"\fw
DECLARE curObject CURSOR FOR "#( T
select 'Name' = name, }y9mNT
'Owner' = user_name(uid) ^Y-]*8;]
from sysobjects T\w?$ s
where user_name(uid)=@OldOwner []a[v%PkG
order by name Ag F,aZU
OPEN curObject JQ4{` =,b
FETCH NEXT FROM curObject INTO @Name, @Owner (JM4R8fR&
WHILE(@@FETCH_STATUS=0) %tG*C,l]
BEGIN Or
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if @Owner=@OldOwner .U T@p
begin 8]&i-VFof
set @OwnerName = @OldOwner + '.' + rtrim(@Name) u%~igt@x
exec sp_changeobjectowner @OwnerName, @NewOwner +cD!1IT:
end 6N)!aT9eo
-- select @name,@NewOwner,@OldOwner s21wxu:
FETCH NEXT FROM curObject INTO @Name, @Owner 7 ^w >Rj
END NPFpq,P>
close curObject pABs!A`N
deallocate curObject wdUBg*X8
GO L%>n>w
10、SQL SERVER中直接循环写入数据 "M|zv
declare @i int E;<l(.Ar
set @i=1 >yY'7Ey
while @i<30 gi0W;q
begin )T;?^kho
insert into test (userid) values(@i) $95h2oXt
set @i=@i+1 UI>Y0O
end sZW^!z
小记存储过程中经常用到的本周,本月,本年函数 hEh}PX:
Dateadd(wk,datediff(wk,0,getdate()),-1) &3yD_P_3
Dateadd(wk,datediff(wk,0,getdate()),6) %/9
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Dateadd(mm,datediff(mm,0,getdate()),0) v@e~k-#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) gUeuUj
Dateadd(yy,datediff(yy,0,getdate()),0) ?B:a|0pf
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 'Ysx=
上面的SQL代码只是一个时间段 R'S0 zp6
Dateadd(wk,datediff(wk,0,getdate()),-1) hAHq\
Dateadd(wk,datediff(wk,0,getdate()),6) 97ql5
就是表示本周时间段. Z!U)I-x&
下面的SQL的条件部分,就是查询时间段在本周范围内的: M`ip~7"
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Yv:55+ e!|
而在存储过程中 y#XbJuN/
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }#X8@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) It{ ;SKeo