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。 Cs2kbG_
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一、基础 eh}|Wd7J
1、说明:创建数据库 B*:W`}G]_c
CREATE DATABASE database-name ?-JW2 E"uT
2、说明:删除数据库 Q7-'5s
drop database dbname q\xsXM
3、说明:备份sql server Zs2;VW4RW
--- 创建 备份数据的 device ]z8Th5a?o
USE master pgBIYeY,
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' YRQ?:a{H
--- 开始 备份 z}F^HQ1
BACKUP DATABASE pubs TO testBack
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4、说明:创建新表 P"+R:O\!g
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) F},kfCFF
根据已有的表创建新表: j{YIVX
A:create table tab_new like tab_old (使用旧表创建新表) #J^ >7v
B:create table tab_new as select col1,col2... from tab_old definition only {t|Q9&
5、说明:删除新表 =!u]t&yv
drop table tabname gts09{"}Y
6、说明:增加一个列 l ;S_ J^S
Alter table tabname add column col type )j!%`g
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。 Cz6bD$5
7、说明:添加主键: Alter table tabname add primary key(col) e[6Me[b
说明:删除主键: Alter table tabname drop primary key(col) iy|;xBI,
8、说明:创建索引:create [unique] index idxname on tabname(col....) 39A|6>-?
删除索引:drop index idxname =R*IOJ
注:索引是不可更改的,想更改必须删除重新建。 ET(/h/r
9、说明:创建视图:create view viewname as select statement cZ3A~dTOR
删除视图:drop view viewname A3|2;4t
10、说明:几个简单的基本的sql语句 mbHMy[R
选择:select * from table1 where 范围 NfZC}
插入:insert into table1(field1,field2) values(value1,value2) +xQj-r)-
删除:delete from table1 where 范围 R)-~5"}~
更新:update table1 set field1=value1 where 范围 @(IA:6GN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4lI&y<F
排序:select * from table1 order by field1,field2 [desc] eoJ*?v
总数:select count as totalcount from table1 [8>#b_>
求和:select sum(field1) as sumvalue from table1 m[v%Qe|~
平均:select avg(field1) as avgvalue from table1 r`i.h ^2De
最大:select max(field1) as maxvalue from table1 8X/SNRk6p
最小:select min(field1) as minvalue from table1 H(kxRPH4@]
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11、说明:几个高级查询运算词 =3PZGdWD
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A: UNION 运算符 N'0nt]&a
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 \H
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B: EXCEPT 运算符 8 %p+:6kP5
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ),H1z`c&I
C: INTERSECT 运算符 <)
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 5=V 29
注:使用运算词的几个查询结果行必须是一致的。 SNf~%B?`L
12、说明:使用外连接 5"bg8hL
A、left outer join: [AYJ(H/
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 &~'i,v|E
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c VVfTFi<
B:right outer join: 9%2he)Yqc
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 92~$Qa\S!
C:full outer join: (a"/cH
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。 @2`nBtk
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二、提升 u+c2
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) z\YLO%Mm
法一:select * into b from a where 1<>1 Mm!;+bM%
法二:select top 0 * into b from a -s\R2_(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) uQKo2B0
insert into b(a, b, c) select d,e,f from b; QcX&q%*0
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) v1/Y0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /#SH`ZK
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1GPBqF
4、说明:子查询(表名1:a 表名2:b) 9A87vs4[
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) /S @iF
5、说明:显示文章、提交人和最后回复时间 R
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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 di7cCn
6、说明:外连接查询(表名1:a 表名2:b) x6ayFq=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5Q: %f
7、说明:在线视图查询(表名1:a ) &da:{
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7>F [7_
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 .3#Xjhebvu
select * from table1 where time between time1 and time2 `aA)n;{/2u
select a,b,c, from table1 where a not between 数值1 and 数值2 %'VzN3Q5V
9、说明:in 的使用方法 J&B5Ll
select * from table1 where a [not] in ('值1','值2','值4','值6') I9xkqj
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ?!.J0q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) bdEIvf7
11、说明:四表联查问题: lq a~ZF*
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 ..... !pHI`FeAV
12、说明:日程安排提前五分钟提醒 "sWsK
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 x$FcF8
13、说明:一条sql 语句搞定数据库分页 G-,0mo
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 OLV3.~T
14、说明:前10条记录 >CwI(vXn
select top 10 * form table1 where 范围 F+L%Ho;@P
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) .
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3Bcv"O,B!{
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 X$?0C{@.}
(select a from tableA ) except (select a from tableB) except (select a from tableC) d(9-T@J
17、说明:随机取出10条数据 AUES;2WL
select top 10 * from tablename order by newid() oE2VJKs<B
18、说明:随机选择记录 h8-uI.RZ
select newid() }a#=c*+_
19、说明:删除重复记录 4~8-^^
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) mHa~c(x
20、说明:列出数据库里所有的表名 =(~Zm B\
select name from sysobjects where type='U' K /%5\h
21、说明:列出表里的所有的 b$- g"F
select name from syscolumns where id=object_id('TableName') b5ul|p
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 4N=
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type JB=L{P J
显示结果: JIqg[Mao
type vender pcs L\!Oj5
电脑 A 1 `u_k?)lK
电脑 A 1 aOQT-C[
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光盘 B 2 keStK8
光盘 A 2 f1?%p)C
手机 B 3 8VuLL<\|
手机 C 3 0k4XVd+Nv
23、说明:初始化表table1 cl |}0Q5
TRUNCATE TABLE table1 IRTWmT
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24、说明:选择从10到15的记录 I3}]MAE
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 8iM:ok
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三、技巧 E,cQ9}/
1、1=1,1=2的使用,在SQL语句组合时用的较多 o 9(x\g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, j8]M}Q$
如: P>$+XrTE
if @strWhere !='' ;jO+<~YP!
begin |;^$IZSsz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere lR mVeq:
end U??OiKVZ+
else `:jF%3ks+0
begin THB[(3q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' zU!d(ge.E
end 7!)VOD8Z
我们可以直接写成 k~F,n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere e2g`T{6M
2、收缩数据库 [xQ.qZ[h&
--重建索引
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DBCC REINDEX ln":j?`
DBCC INDEXDEFRAG @ScC32X
--收缩数据和日志 73_-7'^mQ
DBCC SHRINKDB ;e9&WEG_\
DBCC SHRINKFILE 0-57_";%Q
3、压缩数据库 zQUNvPYM
dbcc shrinkdatabase(dbname) 25r3[gX9`
4、转移数据库给新用户以已存在用户权限 '@IReMl
exec sp_change_users_login 'update_one','newname','oldname' B__e*d:)!m
go .9Dncsnf,`
5、检查备份集 N9M",(WTt}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9xE_Awlc85
6、修复数据库 D9hq$?
ALTER DATABASE [dvbbs] SET SINGLE_USER TI0=nfj
GO 4Lz[bI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK H+@?K6{h
GO ~:|V,1
ALTER DATABASE [dvbbs] SET MULTI_USER /b/ 6*&
GO Og?GYe^_
7、日志清除 NRspi_&4J
SET NOCOUNT ON ^+gD;a|t
DECLARE @LogicalFileName sysname, : #so"O
@MaxMinutes INT, `-K[$V
@NewSize INT y{~tMpo<
USE tablename -- 要操作的数据库名 I|;C}lfp
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W7{^/s5r
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Rm6i[y&
@NewSize = 1 -- 你想设定的日志文件的大小(M) oZdY0n h4
-- Setup / initialize (E~6fb"c
DECLARE @OriginalSize int DJqJ6 z:'
SELECT @OriginalSize = size zsR5"Vi=
FROM sysfiles MmFtG-
WHERE name = @LogicalFileName #&?}h)Jr'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + LlVbY=EX7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {<#b@=G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' jE8}Ho_#)
FROM sysfiles |CQ0{1R1
WHERE name = @LogicalFileName ]86*k%A
CREATE TABLE DummyTrans 9E4^hkD&
(DummyColumn char (8000) not null) +At0V(
DECLARE @Counter INT, '+'h^
@StartTime DATETIME, ULs'oT)K;
@TruncLog VARCHAR(255) 2 OqEyXh
SELECT @StartTime = GETDATE(), OI3j!L2f
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' OKk"S_`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) zZey
EXEC (@TruncLog) d#W^S[[
-- Wrap the log if necessary. Lf%}\0:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired NgF"1E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) bQ&%6'ck
AND (@OriginalSize * 8 /1024) > @NewSize ml!c0<
BEGIN -- Outer loop. BxZ7Bk
SELECT @Counter = 0 kpNp}b8']
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'Z%1Ly^b
BEGIN -- update ->7zVAX
INSERT DummyTrans VALUES ('Fill Log') !XM*y
DELETE DummyTrans 1s(i\&B
SELECT @Counter = @Counter + 1 I7#JT?\}
END %|>D{q6C
EXEC (@TruncLog) Q
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END Vl>KeZ+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + rfzzMV
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6Tc!=lk
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' E}<i?;
FROM sysfiles ~&+ a.@T
WHERE name = @LogicalFileName eZ0-O /_i
DROP TABLE DummyTrans >p" U|
SET NOCOUNT OFF oq|`;k
8、说明:更改某个表 '/AX'U8Y
exec sp_changeobjectowner 'tablename','dbo' )_?h;wh 84
9、存储更改全部表 .MID)PY-
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7#7|+%W0
@OldOwner as NVARCHAR(128), rp2g./2
@NewOwner as NVARCHAR(128) !\O!Du
AS 5g$>J)Ry
DECLARE @Name as NVARCHAR(128) mAJ'>^`^
DECLARE @Owner as NVARCHAR(128) mgM"u94-]
DECLARE @OwnerName as NVARCHAR(128) xO,;4uE
DECLARE curObject CURSOR FOR ]KG.-o30
select 'Name' = name, |WfL'_?$
'Owner' = user_name(uid) e"*ho[
from sysobjects !4 lN[
where user_name(uid)=@OldOwner 4gWlSm)
order by name Lw1[)Vk}E
OPEN curObject ]1W]
FETCH NEXT FROM curObject INTO @Name, @Owner "<%J^Z9G
WHILE(@@FETCH_STATUS=0) 8#o2 qQ2+
BEGIN \w(0k^<7
if @Owner=@OldOwner ;qr?[{G
begin */K]sQZa
set @OwnerName = @OldOwner + '.' + rtrim(@Name) og&h$<uOZt
exec sp_changeobjectowner @OwnerName, @NewOwner LnsYtkbr
end Q&"oh
-- select @name,@NewOwner,@OldOwner y0/FyQs
FETCH NEXT FROM curObject INTO @Name, @Owner |sP0z !)b
END 6BM$u v4
close curObject *X}2
deallocate curObject s#")hMJQ
GO D(&WEmm\B
10、SQL SERVER中直接循环写入数据 |`V=hqe{
declare @i int !$!%era`
set @i=1 iM6(bmc.
while @i<30 b*{UO
begin gr{*wYL
insert into test (userid) values(@i) <HIM
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set @i=@i+1 uY/CiTWr
end {zLgLBM
小记存储过程中经常用到的本周,本月,本年函数 |YfJ#Agm+
Dateadd(wk,datediff(wk,0,getdate()),-1) ?[Ma" l>
Dateadd(wk,datediff(wk,0,getdate()),6) Q~P|=*
Dateadd(mm,datediff(mm,0,getdate()),0) GhjqStjS&l
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?32i1F!
Dateadd(yy,datediff(yy,0,getdate()),0) 'T3xZ?*q=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) eV}H
上面的SQL代码只是一个时间段 e$JATA:j
Dateadd(wk,datediff(wk,0,getdate()),-1) w*o2lg9
Dateadd(wk,datediff(wk,0,getdate()),6) _#{qDG=
就是表示本周时间段. XdOntP *a
下面的SQL的条件部分,就是查询时间段在本周范围内的: WW!-,d{{@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Mm9*$g!R
而在存储过程中 XV`8Vb
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;d]vAj
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) oJ/=&c