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。 Fm j=
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一、基础 nJ3vi}`
1、说明:创建数据库 OKwOugi0
CREATE DATABASE database-name a5`eyL[f
2、说明:删除数据库 }WP-W
drop database dbname |LYKc.xo
3、说明:备份sql server I>w^2(y
--- 创建 备份数据的 device tGqCt9;<
USE master 7$b?m6fmK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' +p/1x'J
--- 开始 备份 Nh)[rx
BACKUP DATABASE pubs TO testBack ekzjF\!y
4、说明:创建新表 4u:0n>nJ1
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #7z|mVzH
根据已有的表创建新表: q/6UK =
A:create table tab_new like tab_old (使用旧表创建新表) K%,$ V,#
B:create table tab_new as select col1,col2... from tab_old definition only uzorLeu
5、说明:删除新表 dhR(_
drop table tabname = hX[
6、说明:增加一个列 Z6=~1'<X
Alter table tabname add column col type QdDtvJLf
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。 ,# "(Z
7、说明:添加主键: Alter table tabname add primary key(col) ^Qh-(u`
说明:删除主键: Alter table tabname drop primary key(col) K=kH%ZK
8、说明:创建索引:create [unique] index idxname on tabname(col....) A'eAu
删除索引:drop index idxname t;Wotfc[#0
注:索引是不可更改的,想更改必须删除重新建。 -gKpL\
9、说明:创建视图:create view viewname as select statement h-'wV${b
删除视图:drop view viewname kP,7Li\
10、说明:几个简单的基本的sql语句 :Z2tig nL
选择:select * from table1 where 范围 YQ,tt<CQ
插入:insert into table1(field1,field2) values(value1,value2) dm^H5D/A
删除:delete from table1 where 范围 U'3Fou}
更新:update table1 set field1=value1 where 范围 }bfn_ G
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *)PG-$6X&
排序:select * from table1 order by field1,field2 [desc] $N.`)S<
总数:select count as totalcount from table1 {$TZ}z"DA
求和:select sum(field1) as sumvalue from table1 E#h~V5Tf
平均:select avg(field1) as avgvalue from table1 <%,'$^'DS
最大:select max(field1) as maxvalue from table1 X!0kK8v
最小:select min(field1) as minvalue from table1 VJ1*|r,
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11、说明:几个高级查询运算词 ic~Z_?p
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A: UNION 运算符 1KJZWZy
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 c/$*%J<
B: EXCEPT 运算符 me'(lQ6^
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。 w#{l4{X|
C: INTERSECT 运算符 }GRMZh_8
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。 6D*chvNA;
注:使用运算词的几个查询结果行必须是一致的。 Zps&[;R$-
12、说明:使用外连接 Z t`j\^4n
A、left outer join: 91;HiILgT
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ?Leyz
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (@?eLJlT
B:right outer join: U?6yke
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 <$C<Ba?;?
C:full outer join: !1-&Y'+
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。 V
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二、提升 W8.j/K:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 2
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法一:select * into b from a where 1<>1 1#!@["
法二:select top 0 * into b from a &l!$Sw-u;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "z/V%ZK~f
insert into b(a, b, c) select d,e,f from b; 6<76O~hNZ
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 0o;~~\fq.
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9%TT>2#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. =5_y<0`4
4、说明:子查询(表名1:a 表名2:b) #O6
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) fIEw(k<*
5、说明:显示文章、提交人和最后回复时间 C
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b o>K &D$J;O
6、说明:外连接查询(表名1:a 表名2:b) fv5C!> t
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c T:n<db,Px
7、说明:在线视图查询(表名1:a ) WJcVQMs
select * from (SELECT a,b,c FROM a) T where t.a > 1; 4@~a<P#
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 afy/K'~
select * from table1 where time between time1 and time2 SEU\}Ni{
select a,b,c, from table1 where a not between 数值1 and 数值2 K!7q!%Ju
9、说明:in 的使用方法 O"QHb|j
select * from table1 where a [not] in ('值1','值2','值4','值6') SauHFl8?
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {tmKCG
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,]U[W
11、说明:四表联查问题: l qXc
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 ..... Ge~,[If+
12、说明:日程安排提前五分钟提醒 %ph"PR/t?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7%tR&F -u
13、说明:一条sql 语句搞定数据库分页 THr8o V5
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 c'~[!,[b<
14、说明:前10条记录 ]F_r6 *<
select top 10 * form table1 where 范围 :Fo4O'UC
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.) n\*JaY
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0k.v0a7%
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 aYBTrOd z
(select a from tableA ) except (select a from tableB) except (select a from tableC) w#<^RKk
17、说明:随机取出10条数据 R%W@~o\p]
select top 10 * from tablename order by newid() OT%V{hD
18、说明:随机选择记录 yI:r7=KO
select newid() 6mAB(X^+
19、说明:删除重复记录 [lOf|^9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) |I/,F;'
20、说明:列出数据库里所有的表名 ,N0uR@GN
select name from sysobjects where type='U' )8bFGX7|
21、说明:列出表里的所有的 @bY?$fj_u
select name from syscolumns where id=object_id('TableName') c G*(C
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 5Fr;
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type A ~XOK;sB
显示结果: iW;}%$lVX
type vender pcs dWjx"7^
电脑 A 1 "kU>~~y,
电脑 A 1 ~r PYJ
光盘 B 2 G#'Q~N
光盘 A 2 drs-mt8
手机 B 3 Vl4Z_viNH
手机 C 3 ?^Pq/VtZ
23、说明:初始化表table1 KZW'O
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TRUNCATE TABLE table1 j;G[%gi6{
24、说明:选择从10到15的记录 L2d:.&5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Y[h#hZ
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三、技巧 W?=$V>)
1、1=1,1=2的使用,在SQL语句组合时用的较多 7|K3WuLL
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 7}A5u,.,ht
如: =g >.X9lr
if @strWhere !='' 0 K/G&c?;=
begin ]L$4Py
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere "I@v&(Am;
end CJm.K
else z'T=]-
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begin keaj3#O
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' NWb}
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end p %L1uwLG
我们可以直接写成 /MhS=gVxM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere HLM;EZ
2、收缩数据库 _/ct=
--重建索引 5cgo)/3M@}
DBCC REINDEX )tScc*=8
DBCC INDEXDEFRAG ))p$vU3
--收缩数据和日志 -.^3;-[
DBCC SHRINKDB ](_{,P
DBCC SHRINKFILE
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3、压缩数据库 @W#fui<<}Y
dbcc shrinkdatabase(dbname) fEB195#@9
4、转移数据库给新用户以已存在用户权限 b~jIv:9T
exec sp_change_users_login 'update_one','newname','oldname' epn#qeX
go !O 4<I_EY{
5、检查备份集 n}0za#G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' is9}ePC7Xu
6、修复数据库 r)OO&. P@j
ALTER DATABASE [dvbbs] SET SINGLE_USER '7t|I6$ow
GO 6k:y$,w
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK IKGTsA;
GO :4%<Rp
ALTER DATABASE [dvbbs] SET MULTI_USER phr2X*Z/)Y
GO 6g}^Q?cpV#
7、日志清除 &{ DR6
SET NOCOUNT ON 1;aF5~&
DECLARE @LogicalFileName sysname, Hw\([j*
@MaxMinutes INT, *}>Bkq9h
@NewSize INT ~:T3|
USE tablename -- 要操作的数据库名 r }ZLf
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ax4*xxU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. O+p]3u
@NewSize = 1 -- 你想设定的日志文件的大小(M) MF&3e#mdB
-- Setup / initialize UOw~rK
DECLARE @OriginalSize int |3S'8OeCI
SELECT @OriginalSize = size IhUW=1&J
FROM sysfiles ,GP!fsK
WHERE name = @LogicalFileName K*HCFqrU"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4sb )^3T
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + xIM8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =Na/3\^WP
FROM sysfiles qx Wgt(Os
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans M8\G>0Hc6
(DummyColumn char (8000) not null) I<c@uXXV;!
DECLARE @Counter INT, >~h>#{&
@StartTime DATETIME, UHr{
@TruncLog VARCHAR(255) {cmo^~[L$
SELECT @StartTime = GETDATE(), ok%EqO
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' a_Z.J3
DBCC SHRINKFILE (@LogicalFileName, @NewSize) tvTWZ`
EXEC (@TruncLog) y*}AX%8`e~
-- Wrap the log if necessary. ]vRVo6@ k
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |^Y*~d<H
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 3aEt>x
AND (@OriginalSize * 8 /1024) > @NewSize U&,r4>V@h>
BEGIN -- Outer loop. 6
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SELECT @Counter = 0 'uPxEu4 >4
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Sc% aJ1
BEGIN -- update /z/hUa
INSERT DummyTrans VALUES ('Fill Log') |.y>[+Qb*
DELETE DummyTrans L& I`
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SELECT @Counter = @Counter + 1 4\&H?:c.
END :/>7$)+
EXEC (@TruncLog) >BJ2v=RA
END |)28=Z|Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }Vs~RJM)}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + \k|_&hG
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' yQ<6p3
FROM sysfiles _2]e1_=
WHERE name = @LogicalFileName Dm>T"4B`/
DROP TABLE DummyTrans Z"l`e0{
SET NOCOUNT OFF 6].yRNy"
8、说明:更改某个表 01&*`0?
exec sp_changeobjectowner 'tablename','dbo' iSOD&J_
9、存储更改全部表 ;n3uV`\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch sXSj OUI
@OldOwner as NVARCHAR(128), | \AbL!u
@NewOwner as NVARCHAR(128) 7J0 ^N7"o
AS Coga-: 2vu
DECLARE @Name as NVARCHAR(128) yonJd
DECLARE @Owner as NVARCHAR(128) dD[v=Z_
DECLARE @OwnerName as NVARCHAR(128) "CIpo/ebL
DECLARE curObject CURSOR FOR `DI{wqV9
select 'Name' = name, u86J.K1Q
'Owner' = user_name(uid) g ^D)x[
from sysobjects JOA%Y;`<#
where user_name(uid)=@OldOwner :X3rd|;kc
order by name \%w7D6dEZ
OPEN curObject ^ze@#Cp
FETCH NEXT FROM curObject INTO @Name, @Owner j'G"ZPw1
WHILE(@@FETCH_STATUS=0) r$b:1 C~
BEGIN !JT<(I2
if @Owner=@OldOwner gUksO!7^1
begin on]\J
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~Y1"k]J
exec sp_changeobjectowner @OwnerName, @NewOwner V->.|[J
end o%vIkXw
-- select @name,@NewOwner,@OldOwner RH<@c^ S
FETCH NEXT FROM curObject INTO @Name, @Owner j)6@q@P/
END /uy&2l
close curObject ^?H\*N4
deallocate curObject 9`ri
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GO sL!;hKK
10、SQL SERVER中直接循环写入数据
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declare @i int ODM>Z8@W/
set @i=1 9)G:::8u7
while @i<30 >g5T;NgH9
begin /AK*aRU^
insert into test (userid) values(@i) P Xyyyir{
set @i=@i+1 2N6Pa(6
end ?3]h~(=
小记存储过程中经常用到的本周,本月,本年函数 NUi{!<
Dateadd(wk,datediff(wk,0,getdate()),-1) *D,v>(
Dateadd(wk,datediff(wk,0,getdate()),6) ~@b9
Dateadd(mm,datediff(mm,0,getdate()),0) ==jkp
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) MuCQxzvkhf
Dateadd(yy,datediff(yy,0,getdate()),0) R*JOiVAC
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) S#dyRTmI
上面的SQL代码只是一个时间段 rnzsfr-|(2
Dateadd(wk,datediff(wk,0,getdate()),-1) |u?k-,uI9
Dateadd(wk,datediff(wk,0,getdate()),6) jD&}}:Dj
就是表示本周时间段. k#l'ko/X
下面的SQL的条件部分,就是查询时间段在本周范围内的: G:E+s(x
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) }0k"SwX
而在存储过程中 "uV0Oj9:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Hl%+F0^?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Wh#_9);