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。 ( *U Mpdj
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一、基础 b&s"x?
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1、说明:创建数据库 fg^$F9@
CREATE DATABASE database-name ~Wf&$p<|
2、说明:删除数据库 VuPa'2
drop database dbname 34&n{ xv
3、说明:备份sql server +{4ziqYj
--- 创建 备份数据的 device $5s?m\!jZz
USE master pma'C\b>
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' LoqS45-)
--- 开始 备份 xW!2[.O5H
BACKUP DATABASE pubs TO testBack ,*wa#[
4、说明:创建新表 Ae;>
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) m fg{% .1
根据已有的表创建新表: o.*8$$
A:create table tab_new like tab_old (使用旧表创建新表) rAM{<
B:create table tab_new as select col1,col2... from tab_old definition only MCjf$pZN]
5、说明:删除新表 _cQTQ
drop table tabname @y2{LUJe
6、说明:增加一个列 >5'C<jc C
Alter table tabname add column col type O#sDZ.EL
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 x9p,j
7、说明:添加主键: Alter table tabname add primary key(col) >01&3-r
说明:删除主键: Alter table tabname drop primary key(col) 'UUIY$V[
8、说明:创建索引:create [unique] index idxname on tabname(col....) xOt%H\*k"
删除索引:drop index idxname AKzhal!
注:索引是不可更改的,想更改必须删除重新建。 :Fm;0R@/k
9、说明:创建视图:create view viewname as select statement D/5 ah_;
删除视图:drop view viewname .|G([O^H
10、说明:几个简单的基本的sql语句 294
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选择:select * from table1 where 范围 QcU&G*
插入:insert into table1(field1,field2) values(value1,value2) u|BD=4*
删除:delete from table1 where 范围 !Z3iu
更新:update table1 set field1=value1 where 范围 DwMq
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Q~MV0<{
排序:select * from table1 order by field1,field2 [desc] x4r\cL1!
总数:select count as totalcount from table1 [>U'P1@ql
求和:select sum(field1) as sumvalue from table1 pIXbr($
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 LK-2e$1
最小:select min(field1) as minvalue from table1 >WVos 4
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11、说明:几个高级查询运算词 )! Jo7SR
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A: UNION 运算符 ds}: t.3}6
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ]+u`E
B: EXCEPT 运算符 lZCTthr\
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ABuK`(f.
C: INTERSECT 运算符 U%.OH?;f
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 *UJ.cQ}
注:使用运算词的几个查询结果行必须是一致的。 7_xQa$U[
12、说明:使用外连接 :D|"hJ
A、left outer join: ^`XQ>-wWue
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。 3x@t7B
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 omisfu_~E
B:right outer join: qb'4x){
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。 h mC.5mY
C:full outer join: gY9HEfB
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。 G6]W'Kk
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二、提升 #;4<dDVy
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >rJ9^rS
法一:select * into b from a where 1<>1 l6]:Zcd0
法二:select top 0 * into b from a l.[S.@\ =.
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Gi]R8?M
insert into b(a, b, c) select d,e,f from b; W@Et
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) 0eP7efy
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 E}LYO:
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4HG;v|Cp
4、说明:子查询(表名1:a 表名2:b) XRARgWj
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) #X1iig+
5、说明:显示文章、提交人和最后回复时间 9f1,E98w_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .K%1{`.|
6、说明:外连接查询(表名1:a 表名2:b) ,/*L|M/&5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *i3\`;^=
7、说明:在线视图查询(表名1:a ) %P@V7n
select * from (SELECT a,b,c FROM a) T where t.a > 1; *|n-Hr
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 `>'%!E9G
select * from table1 where time between time1 and time2 :E`/z@I
select a,b,c, from table1 where a not between 数值1 and 数值2 4}-{sS}MP
9、说明:in 的使用方法 _-mSK/Z
select * from table1 where a [not] in ('值1','值2','值4','值6') <~s{&cL!%#
10、说明:两张关联表,删除主表中已经在副表中没有的信息 *f<+yF{=A
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) .S4c<pMap
11、说明:四表联查问题: r I)Y
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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 ..... .xG3`YH
12、说明:日程安排提前五分钟提醒 ~nLE?>x|Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 XLQt>y)
13、说明:一条sql 语句搞定数据库分页 ul@G{N{L
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 lqdil l\
14、说明:前10条记录 <Cv6wC=
select top 10 * form table1 where 范围 p8gm=
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.) g}\G@7Q
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B'[FnJ8~
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 5AFy6Ab
(select a from tableA ) except (select a from tableB) except (select a from tableC) 1j4tR#L
17、说明:随机取出10条数据 ^phgNzD
select top 10 * from tablename order by newid() qrdA4S
18、说明:随机选择记录 m^?a /
select newid() DD$YMM
19、说明:删除重复记录 F{,<6/ayRz
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) E^'f'\m
20、说明:列出数据库里所有的表名 y(81| c#
select name from sysobjects where type='U' b~oQhU??"
21、说明:列出表里的所有的 ZDn5d%
select name from syscolumns where id=object_id('TableName') 'LC-/_g
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 0o-.m
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type u_31Db<
显示结果: f%ThS42
type vender pcs y@GqAN'DK[
电脑 A 1 L?h'^*F H}
电脑 A 1 MuI>ZoNF
光盘 B 2 #^FDG1=
光盘 A 2
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手机 B 3 dC,a~`%O
手机 C 3 4zo^ b0v
23、说明:初始化表table1 t_ju[xL5B
TRUNCATE TABLE table1 kn5X:@{
24、说明:选择从10到15的记录 76 ]X
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc P6G&3yPt
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三、技巧 `|rF^~6(dR
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,ICn]Pdz@
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 2?c##Izn
如: E!Ljq 3iT`
if @strWhere !='' Q3h_4{w
begin l4O&*,}l##
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere U=ek_FO
end M0) q
else 3fBV
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begin h&|PHI
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :o"9x,
end O-uno{Fd*
我们可以直接写成 ;URvZ! {/Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #S4lRVt5
2、收缩数据库 sV']p#HK0
--重建索引 (8Ptuh6\\2
DBCC REINDEX IoAG !cS
DBCC INDEXDEFRAG /8Wfs5N
--收缩数据和日志 u2 a#qU5*
DBCC SHRINKDB `W=3_
DBCC SHRINKFILE 6<hE]B)
3、压缩数据库 %noByq,?
dbcc shrinkdatabase(dbname) 6,~Y(#
4、转移数据库给新用户以已存在用户权限 _-+xzdGvX
exec sp_change_users_login 'update_one','newname','oldname' 9'"
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go * a ?qV
5、检查备份集 w!kWG,{C
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' '73g~T%$^*
6、修复数据库 'X%5i2
ALTER DATABASE [dvbbs] SET SINGLE_USER ,%=SO 82W
GO rGDx9KR4K!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK T%Nm
GO y&&%%3
ALTER DATABASE [dvbbs] SET MULTI_USER d YliC
GO (/ qOY
7、日志清除 x$L(!ZDh
SET NOCOUNT ON (&osR|/Tq
DECLARE @LogicalFileName sysname, jL6ZHEi#d7
@MaxMinutes INT, 7{JIHY+
@NewSize INT >}7Ml
USE tablename -- 要操作的数据库名 'qy
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t@vVE{`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Kg;u.4.-M
@NewSize = 1 -- 你想设定的日志文件的大小(M) h<0&|s*a)
-- Setup / initialize l^k/Y
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DECLARE @OriginalSize int iwVsq_[]L
SELECT @OriginalSize = size FL|\D
FROM sysfiles ;Pw\p^wz
WHERE name = @LogicalFileName $p;<1+!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6"djX47j
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AY x*Ngn
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &l8eljg
FROM sysfiles }nx5
WHERE name = @LogicalFileName [:BD9V
CREATE TABLE DummyTrans \8<ZPqt9
(DummyColumn char (8000) not null) +Y!
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DECLARE @Counter INT, V] 0T P#
@StartTime DATETIME, UTS.o#d
@TruncLog VARCHAR(255) nl)l:A+q8
SELECT @StartTime = GETDATE(), "p@EY|Zv%I
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,j!%,!n o
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4 \Ig<C9
EXEC (@TruncLog) p6c&vEsNj
-- Wrap the log if necessary. X/BcS[a
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired wrhGZ=k{
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) dTrz7ayH
AND (@OriginalSize * 8 /1024) > @NewSize [,0[\NC
BEGIN -- Outer loop. xf4CM,Z7(
SELECT @Counter = 0 %y|L'C,ge"
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) MLT^7'y
BEGIN -- update UP .4# 1I
INSERT DummyTrans VALUES ('Fill Log') X#Sgf|$
DELETE DummyTrans `k.0d`3(
SELECT @Counter = @Counter + 1 )&{<gyS1
END ,_M
EXEC (@TruncLog) HD_ #-M
END : *8t,f~s^
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Y/<`C
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + XVfw0-O
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' l.Q.G<ol
FROM sysfiles
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WHERE name = @LogicalFileName IgyoBfj\d
DROP TABLE DummyTrans 5q,ZH6\
{
SET NOCOUNT OFF s9rKXY',:l
8、说明:更改某个表 #V$h?`qhwr
exec sp_changeobjectowner 'tablename','dbo' 7!g"q\s
9、存储更改全部表 @L ,4JPk
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1:;S6{oQ
@OldOwner as NVARCHAR(128), .%G>z"Xx
@NewOwner as NVARCHAR(128) S;K5JBX0#
AS rbl7-xhC7
DECLARE @Name as NVARCHAR(128) q}|_]R_y
DECLARE @Owner as NVARCHAR(128) O|AY2QH\
DECLARE @OwnerName as NVARCHAR(128) /T<))@$
DECLARE curObject CURSOR FOR f\vMdY
select 'Name' = name, b*)F7{/Z
'Owner' = user_name(uid) 8pXqgIbmb
from sysobjects 7h#*djef
where user_name(uid)=@OldOwner 2DNB?,uP,'
order by name A}4 ",
OPEN curObject p#0L@!,
FETCH NEXT FROM curObject INTO @Name, @Owner mFrDV,V
WHILE(@@FETCH_STATUS=0) `$t|O&z
BEGIN lx{ '
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if @Owner=@OldOwner 7e:eL5f>~
begin gvFs$X*^:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e'|IRhr
exec sp_changeobjectowner @OwnerName, @NewOwner zQ#2BOx1
end {|B
2$1':
-- select @name,@NewOwner,@OldOwner Y[0mTL4IO
FETCH NEXT FROM curObject INTO @Name, @Owner ,4HZ-|EOZ
END puAjAvIax
close curObject <nU8.?\?~
deallocate curObject H7
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GO *cP(3n3]R
10、SQL SERVER中直接循环写入数据 Yb\d(k$h
declare @i int :/R>0 n,
set @i=1 t{-*@8Ke
while @i<30 : G'a"%x
begin l:+$K s
insert into test (userid) values(@i) <Rfx`mn
set @i=@i+1 k&9[}a*
end Bn{i+8I
小记存储过程中经常用到的本周,本月,本年函数 wx8Qz,Z
Dateadd(wk,datediff(wk,0,getdate()),-1) }R!t/8K
Dateadd(wk,datediff(wk,0,getdate()),6) 4Opf[3]
Dateadd(mm,datediff(mm,0,getdate()),0) 4I8QM&7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) wvmcD%
Dateadd(yy,datediff(yy,0,getdate()),0) 7.kgQ"?&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) H X{K5 +
上面的SQL代码只是一个时间段 k=4C"
Dateadd(wk,datediff(wk,0,getdate()),-1) l5nm.i<M
Dateadd(wk,datediff(wk,0,getdate()),6) vA2>&YDFX
就是表示本周时间段. qVW3oj<2
下面的SQL的条件部分,就是查询时间段在本周范围内的: WK5B8u*<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) lhX4MB"
而在存储过程中 u'T?e+=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 4_-L1WH
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) LP'~7FG