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。 JH0L^p
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一、基础
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1、说明:创建数据库 vc_ 5!K%[
CREATE DATABASE database-name 2!35Tj"RFE
2、说明:删除数据库 $xf{m9 8
drop database dbname ,@Izx
3、说明:备份sql server L4'FL?~I
--- 创建 备份数据的 device *.DTcV
USE master Lh5d2}tcO
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' kWgZIkY
--- 开始 备份 %CP:rAd`M.
BACKUP DATABASE pubs TO testBack \VX~'pkrd/
4、说明:创建新表 &m6x*i-5\f
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) WwF4`kxT
根据已有的表创建新表: eY1$smh t
A:create table tab_new like tab_old (使用旧表创建新表) HwH Wi
B:create table tab_new as select col1,col2... from tab_old definition only n8 eR?'4
5、说明:删除新表 uII:Y{G
drop table tabname 0#rv.rJ{
6、说明:增加一个列 !be6}
Alter table tabname add column col type %?3\gFvBo
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。 $(6 .K-D
7、说明:添加主键: Alter table tabname add primary key(col) LA.xLU3
说明:删除主键: Alter table tabname drop primary key(col) 6%B5hv24v
8、说明:创建索引:create [unique] index idxname on tabname(col....) lll]FJ1
删除索引:drop index idxname H0YxPk)
注:索引是不可更改的,想更改必须删除重新建。 kgvB80$4
9、说明:创建视图:create view viewname as select statement I~$LIdzw
删除视图:drop view viewname ,/;mK_6
10、说明:几个简单的基本的sql语句 U8z$=Wo
选择:select * from table1 where 范围 I%NPc4p
插入:insert into table1(field1,field2) values(value1,value2) |6pNe T[
删除:delete from table1 where 范围 -m:i~^
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更新:update table1 set field1=value1 where 范围 d4#Q<!r
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! I9`R LSn
排序:select * from table1 order by field1,field2 [desc] btK| U
总数:select count as totalcount from table1 =x4:jas
求和:select sum(field1) as sumvalue from table1 bV#U&)|
平均:select avg(field1) as avgvalue from table1 PL#8~e;'
最大:select max(field1) as maxvalue from table1 \1[I(u
最小:select min(field1) as minvalue from table1 Xp=Y<`dX
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11、说明:几个高级查询运算词 T7AFL=
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A: UNION 运算符 QM1-w^
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 |yi3y `f
B: EXCEPT 运算符 Ok+zUA[Wu
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 '|b {
C: INTERSECT 运算符 q9RCXo>Y+1
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 d]OoJK9&&
注:使用运算词的几个查询结果行必须是一致的。 {g2cm'hD
12、说明:使用外连接 IPU'M*|Q
A、left outer join: _,i]ra{%
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 oVsj
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c FKd5]am
B:right outer join: Hut
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 zn T85#]\@
C:full outer join: U
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 HM])m>KeT
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二、提升 0KyujU?sF
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A/N$
法一:select * into b from a where 1<>1 I)E+
法二:select top 0 * into b from a /(w:XTO<
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {_1^ GIIS
insert into b(a, b, c) select d,e,f from b; Z1FO.[FV
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) zi23k=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M#J OX/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. SzR0Mu3uK
4、说明:子查询(表名1:a 表名2:b) [IVT0
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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) Sq&*K9:z
5、说明:显示文章、提交人和最后回复时间 H(ht{.sjI
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )EYsqj
6、说明:外连接查询(表名1:a 表名2:b) %Yg;s'F>#q
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c j=)Cyg3_%
7、说明:在线视图查询(表名1:a ) z0V d(QL
select * from (SELECT a,b,c FROM a) T where t.a > 1; ,9q=2V[GP
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 h'<}N
select * from table1 where time between time1 and time2 F_!6C-z
select a,b,c, from table1 where a not between 数值1 and 数值2 n37C"qJ/i
9、说明:in 的使用方法 ]<q{0.
select * from table1 where a [not] in ('值1','值2','值4','值6') $V~r*#$.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 GA{>=Q_~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $EbxV"b+
11、说明:四表联查问题: 2#LcL
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... J"8bRp=/|
12、说明:日程安排提前五分钟提醒 e|
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 yUQ;tTI
13、说明:一条sql 语句搞定数据库分页 GBvB0kC) c
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 VuwBnQ.2k
14、说明:前10条记录 j?1\E9&4-Q
select top 10 * form table1 where 范围 {nT !|S)$
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.) -[s*R%w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0k>NuIIP
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 J={$q1@lq
(select a from tableA ) except (select a from tableB) except (select a from tableC) -9/YS
17、说明:随机取出10条数据 9U6y<X
select top 10 * from tablename order by newid() ;h_"5/#
18、说明:随机选择记录 mSAuS)YD
select newid() 8Uvf9,I'
19、说明:删除重复记录 #6_?7 (X
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) MC/$:PV
20、说明:列出数据库里所有的表名 sMli! u
select name from sysobjects where type='U' #$%9XD3
21、说明:列出表里的所有的 .9> er
select name from syscolumns where id=object_id('TableName') YL&$cT]1
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。 it\{#rb=4
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 AqvRzi(Y
显示结果: ?V#%^ 57p
type vender pcs a=gTGG"9
电脑 A 1 zzuDI_,/
电脑 A 1 1j6ZSE/*|
光盘 B 2 ^LTLyt)/
光盘 A 2 4QK([q
手机 B 3 JiP]FJ;
手机 C 3 &6,GX7]Fo
23、说明:初始化表table1 *%'4.He7V
TRUNCATE TABLE table1 #O^H?3Q3
24、说明:选择从10到15的记录 [X)+(-J
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc a2UER1Yp"
@g[p>t> *
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三、技巧 2Y&z}4'j
1、1=1,1=2的使用,在SQL语句组合时用的较多 8 +xLi4Pw
"where 1=1" 是表示选择全部 "where 1=2"全部不选, WE4:Jy
如: {O#=%o[
if @strWhere !='' K8{j oh
begin OCo=h|qBp
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b=-<4Vu*\
end b^ly
else ?AyG!F
begin R+gh 2
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' zUXqTcj
end G=!Y ~q g
我们可以直接写成 q NU\XO`H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere wsP3hE' ]
2、收缩数据库 88d0`6K-9
--重建索引 y ']>J+b0
DBCC REINDEX wlC_rRj~
DBCC INDEXDEFRAG qDhz|a#
--收缩数据和日志 1;SW%\M
DBCC SHRINKDB *f.eyg#
DBCC SHRINKFILE M\,0<{
3、压缩数据库 &pK1S>t
dbcc shrinkdatabase(dbname) Pp:(PoH
4、转移数据库给新用户以已存在用户权限 W DY,?
exec sp_change_users_login 'update_one','newname','oldname' x+nrdW+
go Hm`9M.5b
5、检查备份集 @= 6}w_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3w
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6、修复数据库 ,y,NVF
ALTER DATABASE [dvbbs] SET SINGLE_USER i+Px &9o<9
GO h -+vM9j
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK B!!xu
GO ;Y
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ALTER DATABASE [dvbbs] SET MULTI_USER WUGPi'x
GO sBu=@8R]y
7、日志清除 mR[J Xh9s
SET NOCOUNT ON X82sw>Y
DECLARE @LogicalFileName sysname, DuZ51[3_L
@MaxMinutes INT, 0+;.T1?
@NewSize INT /81Ux@,(e
USE tablename -- 要操作的数据库名 `9s5 *;Z
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 B y6:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9HRYk13ae
@NewSize = 1 -- 你想设定的日志文件的大小(M) J@H9nw+Q
-- Setup / initialize W*u Yb|0
DECLARE @OriginalSize int 9X@y*;w<t
SELECT @OriginalSize = size :bW}*0b-
FROM sysfiles ]Tf.KUm
WHERE name = @LogicalFileName mDvZ1aj
SELECT 'Original Size of ' + db_name() + ' LOG is ' + d vkA-9
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + QT9(s\u
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' WHvN6
FROM sysfiles so8isDC'9
WHERE name = @LogicalFileName \UGs_5OT
CREATE TABLE DummyTrans ~ra2Xyl
(DummyColumn char (8000) not null) +~ :1H.
DECLARE @Counter INT, b,~4O~z
@StartTime DATETIME, BGodrb1
@TruncLog VARCHAR(255) wP6~HiC
SELECT @StartTime = GETDATE(), $oH?oD1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' bh6Mh<+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g/mVd;#o
EXEC (@TruncLog) =JOupw
-- Wrap the log if necessary. q3VE\&*^F
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired OlRBvfoh8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7cr+a4 T33
AND (@OriginalSize * 8 /1024) > @NewSize T}$1<^NK
BEGIN -- Outer loop. x7t<F4
SELECT @Counter = 0 @GBS-iT3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C"<l}
BEGIN -- update }7g\1l\
INSERT DummyTrans VALUES ('Fill Log') P@lExF*D1:
DELETE DummyTrans d&(GIH E&d
SELECT @Counter = @Counter + 1 6*S|$lo9B
END }v;@1[.B
EXEC (@TruncLog) Dvo.yn|kB
END -G(z!ed
SELECT 'Final Size of ' + db_name() + ' LOG is ' + oS/<)>\Gv
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + V Z}^1e
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T#|Qexz6 @
FROM sysfiles 8QE0J$d5
WHERE name = @LogicalFileName sn+i[
DROP TABLE DummyTrans H-nk\ K<|
SET NOCOUNT OFF <)uUAh
8、说明:更改某个表 7cK#fh"hvg
exec sp_changeobjectowner 'tablename','dbo' ]N:SB
9、存储更改全部表 /$! /F@^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 37v!:xF!
@OldOwner as NVARCHAR(128), gJ+MoAM"
@NewOwner as NVARCHAR(128) p=coOWOQ
AS Ii?<Lz
DECLARE @Name as NVARCHAR(128) & *B@qQ
DECLARE @Owner as NVARCHAR(128) AGx]srl
DECLARE @OwnerName as NVARCHAR(128) 8,a&i:C
DECLARE curObject CURSOR FOR 9<.FwV>
select 'Name' = name, F6}Pwz[c
'Owner' = user_name(uid) }C}~)qaZv+
from sysobjects ,1Suq\
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where user_name(uid)=@OldOwner c;&m}ImLe.
order by name q<@f3[A
OPEN curObject \"V7O'S)&
FETCH NEXT FROM curObject INTO @Name, @Owner G+=euK2]
WHILE(@@FETCH_STATUS=0) go|/I&
BEGIN ?#<Fxme
if @Owner=@OldOwner y"]?TEd
begin I+!w9o2nZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e/6WhFN#
exec sp_changeobjectowner @OwnerName, @NewOwner @rRBo:0%
end ]sd|u[:k
-- select @name,@NewOwner,@OldOwner d?oupW}uu
FETCH NEXT FROM curObject INTO @Name, @Owner 1C{n!l
END ivb&J4?y
close curObject !qV{OXdrB
deallocate curObject gLsl/G
GO m[LIM}Gu
10、SQL SERVER中直接循环写入数据 !<h*\%;
declare @i int (Vf&,b@U_
set @i=1 T8Gx oNm
while @i<30 c;xL.
begin d}EGI
insert into test (userid) values(@i) x4CrWm
set @i=@i+1 sw[1T_S>
end L
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小记存储过程中经常用到的本周,本月,本年函数 o*_[3{FU
Dateadd(wk,datediff(wk,0,getdate()),-1) (8?t0}#t
Dateadd(wk,datediff(wk,0,getdate()),6) W|NzdxCY
Dateadd(mm,datediff(mm,0,getdate()),0) X)e6Y{vO
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) f+}?$'
Dateadd(yy,datediff(yy,0,getdate()),0) B0?E$8a
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |+~CdA
上面的SQL代码只是一个时间段 Pg{Dy>&2`I
Dateadd(wk,datediff(wk,0,getdate()),-1) pZ/x,b#.
Dateadd(wk,datediff(wk,0,getdate()),6) 7
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就是表示本周时间段. C;0H _
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4rO07)~l
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) b*',(J94
而在存储过程中 RgHPYf{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 9.m_3"s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~%qHJ4C