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。 >t u3m2
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一、基础 r4jW=?|
1、说明:创建数据库 =PyU9C-@
CREATE DATABASE database-name ?3Wh.%n
2、说明:删除数据库 -yOrNir}W
drop database dbname =35^k-VS
3、说明:备份sql server VB*$lxX
--- 创建 备份数据的 device zl46E~"]x
USE master 2}1(j
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~.mnxn
--- 开始 备份 5)o-$1s A
BACKUP DATABASE pubs TO testBack :h?"0,
4、说明:创建新表 {AqN@i
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) B[ooT3V
根据已有的表创建新表: A\lnH5A
A:create table tab_new like tab_old (使用旧表创建新表) GDP@M)~6*
B:create table tab_new as select col1,col2... from tab_old definition only 1=OXi!G
5、说明:删除新表 ;PI=jp
drop table tabname /iNCb&[
6、说明:增加一个列 z?_c:]D
Alter table tabname add column col type ;JA2n\iP,
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 I-4csw<Qy
7、说明:添加主键: Alter table tabname add primary key(col) gIep6nq1`|
说明:删除主键: Alter table tabname drop primary key(col) BqK|4-Pf
8、说明:创建索引:create [unique] index idxname on tabname(col....) k}l5v)m
删除索引:drop index idxname J@(=#z8xS
注:索引是不可更改的,想更改必须删除重新建。 A/%K= H?
9、说明:创建视图:create view viewname as select statement c[?S}u|['
删除视图:drop view viewname Nqp%Z7G
10、说明:几个简单的基本的sql语句 p0? XR
选择:select * from table1 where 范围 z}yntY]n
插入:insert into table1(field1,field2) values(value1,value2) c*K-?n9YMz
删除:delete from table1 where 范围 -ZH]i}$
更新:update table1 set field1=value1 where 范围 3zY"9KUN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ?s #DD,
排序:select * from table1 order by field1,field2 [desc] "P.7FD
总数:select count as totalcount from table1 VR2BdfKU,
求和:select sum(field1) as sumvalue from table1 ,\4@Ao
平均:select avg(field1) as avgvalue from table1 \TkBV?W
最大:select max(field1) as maxvalue from table1 8(q4D K\5u
最小:select min(field1) as minvalue from table1 zm\=4^X
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11、说明:几个高级查询运算词 [oKc<o7)~"
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A: UNION 运算符 /!oi`8D
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。 ${ad[hs
B: EXCEPT 运算符 J %jfuj
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 AnG/A!G
C: INTERSECT 运算符 _sbZyL
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ~<Uwumv
注:使用运算词的几个查询结果行必须是一致的。 tx Lo=
12、说明:使用外连接 KnbT2
A、left outer join: _;W}_p}q{
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 m*|3
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {l.) *#O
B:right outer join: 'y}l9alF
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 xKEHNgen
C:full outer join: tn+i5Eso
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 A5z`_b4f
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二、提升 .<^dv?@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l~AmHw
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法一:select * into b from a where 1<>1 7&/iuP$.
法二:select top 0 * into b from a 7=u\D
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) LR]P?
insert into b(a, b, c) select d,e,f from b; /@lXQM9T
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) z(iB$;M
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 v)!Rir5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 'h%)@q)J)
4、说明:子查询(表名1:a 表名2:b) &!2
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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) M/:kh,3
5、说明:显示文章、提交人和最后回复时间 pq#Hca[
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b > YKvwbCf8
6、说明:外连接查询(表名1:a 表名2:b) ?%i|].<-'
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Cd#[b)d ?^
7、说明:在线视图查询(表名1:a ) FGG Fi(
select * from (SELECT a,b,c FROM a) T where t.a > 1; PbJn8o
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 *J=`"^BO
select * from table1 where time between time1 and time2 66fvS}x
select a,b,c, from table1 where a not between 数值1 and 数值2 s[nXr
9、说明:in 的使用方法 BC%t[H} >R
select * from table1 where a [not] in ('值1','值2','值4','值6') _OZrH(8
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ' ]l,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~A}"s-Kq5
11、说明:四表联查问题: .d^8w97
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 ..... &sh
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12、说明:日程安排提前五分钟提醒 0SwWLq
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 FcdbL,}=<
13、说明:一条sql 语句搞定数据库分页 yDWzsA/X
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 zK(9k0+s
14、说明:前10条记录 R#1h.8
select top 10 * form table1 where 范围 ~ULuX"n
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.) =<y$5"|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =S4_^UY;
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 j5|PQOK
(select a from tableA ) except (select a from tableB) except (select a from tableC) D0v!fF~
17、说明:随机取出10条数据 0rxlN
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select top 10 * from tablename order by newid() pjvChl5
18、说明:随机选择记录 P7&a~N$T6W
select newid() `8\_ ]w0
19、说明:删除重复记录 /P<RYA~
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %L=roqz
20、说明:列出数据库里所有的表名 _' Xt
select name from sysobjects where type='U' A?ma5h
21、说明:列出表里的所有的 u^s{r`/
select name from syscolumns where id=object_id('TableName') y;keOI!
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。 ':R)i.TS
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 iSUn}%YFz!
显示结果: "uDLty?*k
type vender pcs ;}#tm9S;
电脑 A 1 J~V`"uo
电脑 A 1 2.p7fu
光盘 B 2 =Jg5J5
光盘 A 2 h2`W~g_
手机 B 3 yP :>vFd7
手机 C 3 ~!E%GCyFy
23、说明:初始化表table1 6c^2Nl8e
TRUNCATE TABLE table1 4pJOJ!?
24、说明:选择从10到15的记录 z
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc dz5a! e
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三、技巧 cVV @MC
1、1=1,1=2的使用,在SQL语句组合时用的较多 wo#,c(
"where 1=1" 是表示选择全部 "where 1=2"全部不选, v[7iWBqJ
如: s'7PHP)LOJ
if @strWhere !='' xM+_rU
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begin 24g\xNnt
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $a@T:zfe
end v3*y43
else ZXJ]==
begin |>Ld'\i8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Mzg zOM
end KD<smwXjG
我们可以直接写成 4 ZUTF3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2\4ammwT
2、收缩数据库 04j]W]8#
--重建索引 =8o$
DBCC REINDEX ]\JLlQ}#H
DBCC INDEXDEFRAG hR4\:s+[
--收缩数据和日志 .S_7R/2(?
DBCC SHRINKDB aAbK{=/y_!
DBCC SHRINKFILE &g.do?
3、压缩数据库 cko^_V&x
dbcc shrinkdatabase(dbname) wB(X(nr
4、转移数据库给新用户以已存在用户权限 !&eKq?P{j
exec sp_change_users_login 'update_one','newname','oldname' 7Mj:bm&9
go M1mx {<]A
5、检查备份集 {py"Ob_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' {`ghX%M(l
6、修复数据库 v 1.8]||^
ALTER DATABASE [dvbbs] SET SINGLE_USER /g`!Zn8a
GO JhU"akoK
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK XsEotW
GO GXnrVI
ALTER DATABASE [dvbbs] SET MULTI_USER De-hHY{>
GO gX%"Ki7.
7、日志清除 6(1S_b=a
SET NOCOUNT ON ?Tlt(%f
DECLARE @LogicalFileName sysname, u\AL`'v
@MaxMinutes INT, 7WMF8(j5
@NewSize INT nb~592u
USE tablename -- 要操作的数据库名 U [R[VY7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 f=EWr8mno
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ql1J?9W
@NewSize = 1 -- 你想设定的日志文件的大小(M) kf:Nub+h t
-- Setup / initialize si,)!%b
DECLARE @OriginalSize int ?onEqH>
SELECT @OriginalSize = size zl3GWj|?\7
FROM sysfiles RxYC]R^78
WHERE name = @LogicalFileName ;Tec)Fl
SELECT 'Original Size of ' + db_name() + ' LOG is ' + e~ZxDAd
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + t?(fDWd|-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' W; zzc1v
FROM sysfiles )Tl]1^
WHERE name = @LogicalFileName 9*2Q'z}_
CREATE TABLE DummyTrans =T- jG_.H
(DummyColumn char (8000) not null) Y-s6Z\
DECLARE @Counter INT, Yh["IhjR
@StartTime DATETIME, jX;$g>P
@TruncLog VARCHAR(255) 4c]=kb GW
SELECT @StartTime = GETDATE(), 96d&vm~m1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1wg#4h43l
DBCC SHRINKFILE (@LogicalFileName, @NewSize) u- }@^Y$M
EXEC (@TruncLog) Bfu/w
-- Wrap the log if necessary. i*)BFV_-
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tc|PN+v;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 4J{W8jX
AND (@OriginalSize * 8 /1024) > @NewSize `uof\D<']
BEGIN -- Outer loop. ^4~?]5Y\
SELECT @Counter = 0 ]^0mh["
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3De(:c)@
BEGIN -- update 9 >"}||))
INSERT DummyTrans VALUES ('Fill Log') )eVn1U2*z.
DELETE DummyTrans M#.dF{%%
SELECT @Counter = @Counter + 1 v[\Z^pccgj
END XE$;Z'Qhjm
EXEC (@TruncLog) %%T?LRv
END C*stj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + M%#F"^8v
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + +[`
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' GOUO
FROM sysfiles "
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WHERE name = @LogicalFileName N5b^
DROP TABLE DummyTrans 'x,6t66*"l
SET NOCOUNT OFF hiEosI
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8、说明:更改某个表 5p>rQq0
exec sp_changeobjectowner 'tablename','dbo' ;--p/h*.
9、存储更改全部表 *pYawT
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0O?\0k;o
@OldOwner as NVARCHAR(128), #('GGzL6c
@NewOwner as NVARCHAR(128) C'6c,
AS e8 c.&j3m
DECLARE @Name as NVARCHAR(128) bHg 0,N
DECLARE @Owner as NVARCHAR(128) %F87"v~
DECLARE @OwnerName as NVARCHAR(128) xQ!
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DECLARE curObject CURSOR FOR ZfibHivz
select 'Name' = name, pN{XGkX.
'Owner' = user_name(uid) k{
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from sysobjects 6~O;t'd
where user_name(uid)=@OldOwner f{-,"6Y1
order by name u/apnAW@M
OPEN curObject #G\Ae:O
FETCH NEXT FROM curObject INTO @Name, @Owner a/n~#5-
WHILE(@@FETCH_STATUS=0) (\%J0kR3[
BEGIN }vd72PB
if @Owner=@OldOwner pQoZDD@B$
begin RREl($$p
set @OwnerName = @OldOwner + '.' + rtrim(@Name) E
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exec sp_changeobjectowner @OwnerName, @NewOwner ]Na; b
end cv_t2m
-- select @name,@NewOwner,@OldOwner : cPV08i
FETCH NEXT FROM curObject INTO @Name, @Owner fS3%
END XCT3:db
close curObject %3yrX>Js
deallocate curObject m A('MS2
GO blUS6"kV}
10、SQL SERVER中直接循环写入数据 3uL$+F
declare @i int o QR?H
set @i=1 t!59upbN}3
while @i<30 rAk;8)O$
begin Rl'xEtaN
insert into test (userid) values(@i) O&Y22mu
set @i=@i+1 b_)SMAsO7
end ir5eR}H
小记存储过程中经常用到的本周,本月,本年函数 ]/|DCxQ
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) 0x#
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Dateadd(mm,datediff(mm,0,getdate()),0) s
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1ZXRH;J40
Dateadd(yy,datediff(yy,0,getdate()),0) zVis"g`
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) P]7s1kgaS
上面的SQL代码只是一个时间段 ZU`HaL$
Dateadd(wk,datediff(wk,0,getdate()),-1) AD>/#Ul
Dateadd(wk,datediff(wk,0,getdate()),6) 9hgIQl
就是表示本周时间段. s>=$E~qq
下面的SQL的条件部分,就是查询时间段在本周范围内的: f[q_eY
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (`<B#D;
而在存储过程中 nv3TxG
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?4t~z 1.f
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Ch]q:o4