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。 : H;S"D
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一、基础 i4i9EvWp
1、说明:创建数据库 U&])ow):
CREATE DATABASE database-name _";w*lg}
2、说明:删除数据库 PVlCj
drop database dbname o5&b'WUJ=
3、说明:备份sql server :
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--- 创建 备份数据的 device .tG3g:
USE master ,hI$nF0}p
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [q!]Ds"
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--- 开始 备份 Gn^lF7yE
BACKUP DATABASE pubs TO testBack @br)m](@
4、说明:创建新表 vb>F)po1}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sS
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根据已有的表创建新表: d)!'5ZrM
A:create table tab_new like tab_old (使用旧表创建新表) p1d%&e
B:create table tab_new as select col1,col2... from tab_old definition only SJP3mq/^K
5、说明:删除新表 }hg=#*
drop table tabname myX&Z F_9
6、说明:增加一个列 Q >[>{N&\
Alter table tabname add column col type KO8{eT9d
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 co8R-AB
7、说明:添加主键: Alter table tabname add primary key(col) l VD{Y`)
说明:删除主键: Alter table tabname drop primary key(col) P-2DBNB7
8、说明:创建索引:create [unique] index idxname on tabname(col....) 'J} ?'{.
删除索引:drop index idxname 0`7yPq*
注:索引是不可更改的,想更改必须删除重新建。 AA^K/y
9、说明:创建视图:create view viewname as select statement 9;6)b0=$
删除视图:drop view viewname 0M;El2
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10、说明:几个简单的基本的sql语句 QnS^ G{
选择:select * from table1 where 范围 ._tEDY/1m
插入:insert into table1(field1,field2) values(value1,value2) 5`fUR/|[
删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 vv,<#4d
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! QAxy?m,'
排序:select * from table1 order by field1,field2 [desc] %XukiA+
总数:select count as totalcount from table1 }(u:K}8
求和:select sum(field1) as sumvalue from table1 PRiE2Di2S
平均:select avg(field1) as avgvalue from table1 kZ@UQ{>`
最大:select max(field1) as maxvalue from table1 wg0_J<y]
最小:select min(field1) as minvalue from table1 4_VgJ9@
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11、说明:几个高级查询运算词 9F3,
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A: UNION 运算符 >e/>@ J*
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。 vd#)+
B: EXCEPT 运算符 0/ 33Z Oc
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。 ~
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C: INTERSECT 运算符 w=_^n]`R
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。
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注:使用运算词的几个查询结果行必须是一致的。 ,^e2ma|z
12、说明:使用外连接 b(|&e
A、left outer join: :F"IOPfU5[
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。 <& PU%^Ha
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 sS{Co8EJn
B:right outer join: ^wZx=kas
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。 TC<Rg?&yb
C:full outer join: 6c^?DLy9B
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。 e)?}2
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二、提升 ]'%
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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) ;Ngk"5
法一:select * into b from a where 1<>1 OHAU@*[lM
法二:select top 0 * into b from a }X8P5c!\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #J/RI[a
insert into b(a, b, c) select d,e,f from b; Ig!0A}f
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) EMe1!)
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 a_+3, fP
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. G|nBja8vm
4、说明:子查询(表名1:a 表名2:b) ]}'bRq*]
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) /PSXuVtu5
5、说明:显示文章、提交人和最后回复时间 -?#iPvk6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b o9|
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6、说明:外连接查询(表名1:a 表名2:b) |(W04Wp"@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c egA*x*8
7、说明:在线视图查询(表名1:a ) l*hWws[
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2>X yrG
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 mgH~GKf^
select * from table1 where time between time1 and time2 T$0)un
select a,b,c, from table1 where a not between 数值1 and 数值2 ;|XX^
9、说明:in 的使用方法 0#'MR.,
select * from table1 where a [not] in ('值1','值2','值4','值6') g"'BsoJ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 zx8@4?bK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 9C?SEbC
11、说明:四表联查问题: RrBG=V
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 5!'1;GLs
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {ly <%Q7j
13、说明:一条sql 语句搞定数据库分页 ]m`:T
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ]pB5cq7o
14、说明:前10条记录 q,7W,<-
select top 10 * form table1 where 范围 whw+
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) m.ka%h$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) r$4d4xtK
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 E7R%G OH
(select a from tableA ) except (select a from tableB) except (select a from tableC) O{c#&/ .K
17、说明:随机取出10条数据 Pw]+6
select top 10 * from tablename order by newid() _oa*E2VN
18、说明:随机选择记录 a.UYBRP/l
select newid() Pm^FSw"
19、说明:删除重复记录 9 9:.j=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #w5%^HwO
20、说明:列出数据库里所有的表名 tR9iFv_
select name from sysobjects where type='U' ?m5"|f\
21、说明:列出表里的所有的 'z}9BGR!
select name from syscolumns where id=object_id('TableName')
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 4w9=z,
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type d5L BL'/o
显示结果: 6v scu2
type vender pcs X6B,Mply
电脑 A 1 Qh8pOUD0l}
电脑 A 1 p3-~cr.LD
光盘 B 2 "h1ek*(?<
光盘 A 2 %$b}o7U"s
手机 B 3 UzSDXhzObf
手机 C 3 /#{~aCOi)
23、说明:初始化表table1 qB@N|Bb
TRUNCATE TABLE table1 $;=^|I4E
24、说明:选择从10到15的记录 ktfxb<%
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc J3 oUtu
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三、技巧 5G'2 Wby'#
1、1=1,1=2的使用,在SQL语句组合时用的较多 a(fiW%eFb
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }+`,AC`RM
如: Q:
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if @strWhere !='' 46
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begin gGCr~.5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere P5G0fq7
end DsxNg
else h*<`ct xL
begin .#tA .%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !a V:T&6
end N@Ap|`Ei
我们可以直接写成 T:%0i8p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere D` cy.},L
2、收缩数据库 5IzCQqOPgX
--重建索引 8f~*T
DBCC REINDEX !W&|kvT^
DBCC INDEXDEFRAG U74L:&yLI
--收缩数据和日志 9_svtO ]P
DBCC SHRINKDB @S~n^v,)
DBCC SHRINKFILE \cX9!lHl
3、压缩数据库 vnbY^ASdw
dbcc shrinkdatabase(dbname) t6e6v=.Pg
4、转移数据库给新用户以已存在用户权限 Y/m-EL
exec sp_change_users_login 'update_one','newname','oldname' )iIsnM
go t vW0 W
5、检查备份集 \jZmu
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' B&KIM{j\
6、修复数据库 BUi,+NdIk
ALTER DATABASE [dvbbs] SET SINGLE_USER Cv>~%<
GO h0 %M+g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK D=D.s)ns*
GO }YC=q
ALTER DATABASE [dvbbs] SET MULTI_USER w0yzC0yBk
GO Xe`$SNM
7、日志清除 ^f(El(w
SET NOCOUNT ON 4R01QSbd
DECLARE @LogicalFileName sysname, &,Rye Q
@MaxMinutes INT, k&K'FaM!
@NewSize INT {<Y!'WL{
USE tablename -- 要操作的数据库名 1 Cz}|#U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 eUu<q/FUMj
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~(c<M>Q8
@NewSize = 1 -- 你想设定的日志文件的大小(M) :SMf
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-- Setup / initialize 1z,P"?Q
DECLARE @OriginalSize int 3h o'\Ysu/
SELECT @OriginalSize = size +Swl$ab
FROM sysfiles F2(^OFh
WHERE name = @LogicalFileName cF9ZnT.
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4},Y0 QXw
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + eA(FWO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' )`|`PB
FROM sysfiles 8c%N+E]
WHERE name = @LogicalFileName j{tr''yN
CREATE TABLE DummyTrans w9x5 IRW k
(DummyColumn char (8000) not null) E6Uj8]P`
DECLARE @Counter INT, ?u{Mz9:?HT
@StartTime DATETIME, !qH)ttW
@TruncLog VARCHAR(255) ^{8CShUCv
SELECT @StartTime = GETDATE(), X`E}2|q'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {~\:4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ]E.FBGT
EXEC (@TruncLog) Ka)aBU9
-- Wrap the log if necessary. 1csbuR?
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired o {q8An)
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) WwKpZ67$R
AND (@OriginalSize * 8 /1024) > @NewSize 3-0jxx(
BEGIN -- Outer loop. b9b`%9/L
SELECT @Counter = 0 #~|esr/wf
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) w17{2']
BEGIN -- update "yU<X\ni
INSERT DummyTrans VALUES ('Fill Log') )iPU
DELETE DummyTrans U~zy;MT
SELECT @Counter = @Counter + 1 CX{M@x3m
END t08[3Q&
EXEC (@TruncLog) g+&wgyq5
END "KC3+:tm
SELECT 'Final Size of ' + db_name() + ' LOG is ' + B.b sU
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 0!axAvBV
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles ay{]Vqi9
WHERE name = @LogicalFileName *`bES V
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DROP TABLE DummyTrans 6l"4F6
SET NOCOUNT OFF @'J~(#}
8、说明:更改某个表 tg%Sn+:
exec sp_changeobjectowner 'tablename','dbo' O15~\8#'
9、存储更改全部表 3Dh{#"88
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1iM(13jW
@OldOwner as NVARCHAR(128), d-8g
@NewOwner as NVARCHAR(128) $iH
AS 4;IZ}9|G
DECLARE @Name as NVARCHAR(128) >;xkiO>Y
DECLARE @Owner as NVARCHAR(128) !0X"^VB
DECLARE @OwnerName as NVARCHAR(128) K_X(j$2Xc
DECLARE curObject CURSOR FOR jfa<32`0E
select 'Name' = name, 94rx4"AN8;
'Owner' = user_name(uid) N45@)s!F9j
from sysobjects BSEP*#s
where user_name(uid)=@OldOwner Bq,Pk5b
order by name pqbKPpG
OPEN curObject D/2;b;-
FETCH NEXT FROM curObject INTO @Name, @Owner u<+RA
WHILE(@@FETCH_STATUS=0) MLDAr dvK
BEGIN Zc9S[ivq
if @Owner=@OldOwner +sd':vE
begin U!lWP#m
set @OwnerName = @OldOwner + '.' + rtrim(@Name) R~dWblv
exec sp_changeobjectowner @OwnerName, @NewOwner EiA_9%<
end ar`}+2Qh0
-- select @name,@NewOwner,@OldOwner 2m&?t_W
FETCH NEXT FROM curObject INTO @Name, @Owner 0+rBGk
END @]],H0
close curObject M!PK3
deallocate curObject t |:XSJ9
GO Fow{-cs_p
10、SQL SERVER中直接循环写入数据 E3_ 5~>
declare @i int !-B|x0fs
set @i=1 }OgZZ8-_M
while @i<30 ab_EH}j1\q
begin vb\R~%@T,
insert into test (userid) values(@i) f(-3d*g
set @i=@i+1 d\ Xijy
end O;#0Yg
小记存储过程中经常用到的本周,本月,本年函数 "[ >ql1t{b
Dateadd(wk,datediff(wk,0,getdate()),-1) Op iVQr:
Dateadd(wk,datediff(wk,0,getdate()),6) `~qVo4V6Z
Dateadd(mm,datediff(mm,0,getdate()),0) Q>/[*(.Wd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %BkPkQA
Dateadd(yy,datediff(yy,0,getdate()),0) Hg[AulNna
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~</H>Jd
上面的SQL代码只是一个时间段 <QK2Wc_}-"
Dateadd(wk,datediff(wk,0,getdate()),-1) ? ,!C0t s
Dateadd(wk,datediff(wk,0,getdate()),6) ~0{F,R.$
就是表示本周时间段. vqwSOh|P9
下面的SQL的条件部分,就是查询时间段在本周范围内的: #X<s_.7DJ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )-LSn
而在存储过程中 ZV:0:k.x
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) g\?7M1~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) kQtnT7