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。 "Vh3hnS~
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一、基础 R !g'zS'
1、说明:创建数据库 `#HtVI
CREATE DATABASE database-name yq. <,b=87
2、说明:删除数据库 f~Y;ZvB
drop database dbname 4`yE'%6.}
3、说明:备份sql server mi[t1cN)=
--- 创建 备份数据的 device !Gob `# r
USE master ]1hyv m3
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' /pY-how%!
--- 开始 备份 GDF/0-/Z
BACKUP DATABASE pubs TO testBack 8;6j
4、说明:创建新表 ')N[)&&Q{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1WjNF i
根据已有的表创建新表: Zt_~Zxn3
A:create table tab_new like tab_old (使用旧表创建新表) (4o<U%3kGq
B:create table tab_new as select col1,col2... from tab_old definition only &!P' M
5、说明:删除新表 X*cDn.(I
drop table tabname &Va="HNKt
6、说明:增加一个列 E{;F4wT_@
Alter table tabname add column col type v[;R(pt?
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。 )
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7、说明:添加主键: Alter table tabname add primary key(col) e"oTlB
说明:删除主键: Alter table tabname drop primary key(col) /H4Z.|@
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;w/@_!~
删除索引:drop index idxname ~c,CngeL0
注:索引是不可更改的,想更改必须删除重新建。 i<0_sxfUD
9、说明:创建视图:create view viewname as select statement m)7Ql!l
删除视图:drop view viewname vB74r]'F
10、说明:几个简单的基本的sql语句 !3F3E8%
选择:select * from table1 where 范围 Su/8P[q_
插入:insert into table1(field1,field2) values(value1,value2) {W+IUvn
删除:delete from table1 where 范围 6VUs:iO1j5
更新:update table1 set field1=value1 where 范围 KH$|wv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! s&hJ[$i
排序:select * from table1 order by field1,field2 [desc] JBhM*-t(M1
总数:select count as totalcount from table1 k5M5bH',
求和:select sum(field1) as sumvalue from table1 IOA2/WQu
平均:select avg(field1) as avgvalue from table1 xU/7}='T
最大:select max(field1) as maxvalue from table1 |kY}G3/
最小:select min(field1) as minvalue from table1 M*!WXQlud
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11、说明:几个高级查询运算词 <%o9*)F
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A: UNION 运算符 44NMof8N
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。 Gv[s86AP,
B: EXCEPT 运算符 1=Z!ZY}}e
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。 3Ccy %;
C: INTERSECT 运算符 7}:+Yx
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。 1 |
注:使用运算词的几个查询结果行必须是一致的。 Brtsig,4
12、说明:使用外连接 WNY:HH
A、left outer join: NnH]c+
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。 NSa6\.W)
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 >?Duz+W)
B:right outer join: 1:JwqbZKJ
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。 [#=IKsO'R6
C:full outer join: {J1iheuS}
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。 %afN&T
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二、提升 G9^xv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?7>"ZGDe>
法一:select * into b from a where 1<>1 Ptz##o'{5
法二:select top 0 * into b from a FsO_|r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) y8_$YA/g
insert into b(a, b, c) select d,e,f from b; b)@D@K"5
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ?3lAogB
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ph}%Ay$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 2x>7>;>
4、说明:子查询(表名1:a 表名2:b) G6QD`ED
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) +h@.P B^`~
5、说明:显示文章、提交人和最后回复时间 ~-<MoCm!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2X<%BFsE
6、说明:外连接查询(表名1:a 表名2:b) %x.du9
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c HfZ ^ED"}
7、说明:在线视图查询(表名1:a ) 0 N"N$f
select * from (SELECT a,b,c FROM a) T where t.a > 1; 'W,*mfB
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 j7U&a}(
select * from table1 where time between time1 and time2
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select a,b,c, from table1 where a not between 数值1 and 数值2 PB
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9、说明:in 的使用方法 e|?eY)_
select * from table1 where a [not] in ('值1','值2','值4','值6') 2eHVl.C5
10、说明:两张关联表,删除主表中已经在副表中没有的信息 "fr{:'HX
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Uks%Mo9on
11、说明:四表联查问题: h%U}Y5Ps~
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 ..... /IN#1I!K
12、说明:日程安排提前五分钟提醒 5 w(nttYH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 HKr}"`I.
13、说明:一条sql 语句搞定数据库分页 s7afj 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 RC}m]!Uz
14、说明:前10条记录 w3ATsIw
select top 10 * form table1 where 范围 CuD}Uo+u
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.) O wuc9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &r.M~k
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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 C{,^4Eh3r
(select a from tableA ) except (select a from tableB) except (select a from tableC) 9dw*
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17、说明:随机取出10条数据 KF6C=,Yc%
select top 10 * from tablename order by newid() p^|6 /b
18、说明:随机选择记录 wZZ~!"O&
select newid() ~4pP(
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19、说明:删除重复记录 ,f{w@Er
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) pHuR_U5*?
20、说明:列出数据库里所有的表名 ^B0Qk:%P^N
select name from sysobjects where type='U' t7l{^d_L
21、说明:列出表里的所有的 }toe'6
select name from syscolumns where id=object_id('TableName') m~
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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。 cF4,dnI
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 aZ$5"
显示结果: Y0.'u{J*
type vender pcs S2DG=hi`GK
电脑 A 1 J$sBfOD
电脑 A 1 ;W+8X-B
光盘 B 2 0PqI^|!
光盘 A 2 #bBh. ^
手机 B 3 UOsK(mB
手机 C 3 #M{qMJHDo
23、说明:初始化表table1 ,#FP]$FK
TRUNCATE TABLE table1 /!2`pv
24、说明:选择从10到15的记录 H<[~V0=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc )l$}plT4
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三、技巧 "!D y[J
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^~I@]5Pq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +}N'Xa/Jt
如: (ix.
if @strWhere !='' l_/(J)|a
begin CvmIDRP*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Nf^<pT[*
end %s"&|32
else C+uW]]~I)
begin *2u~5Kc<
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' BGBHA"5fz
end mM72>1~L*
我们可以直接写成 EwX&Cj".
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |dqHpogh
2、收缩数据库 y/y~<-|<@
--重建索引 G~o!u8^;
DBCC REINDEX 5LB{b]w7m
DBCC INDEXDEFRAG Jn^b}bk t
--收缩数据和日志 Hc=QSP
DBCC SHRINKDB &n
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DBCC SHRINKFILE Bp_R"DS7A
3、压缩数据库 (z>t 4(%\
dbcc shrinkdatabase(dbname) uZtN,Un
4、转移数据库给新用户以已存在用户权限 +:uz=~mo`
exec sp_change_users_login 'update_one','newname','oldname' 6_4B!
go 7M~sol[*
5、检查备份集 {='Bd6_=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' eFG(2OVg}M
6、修复数据库 jtlRom}
ALTER DATABASE [dvbbs] SET SINGLE_USER *9"x0bth
GO s6@mXO:H^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o^vX\a?`u
GO l@Vv%w9H
ALTER DATABASE [dvbbs] SET MULTI_USER .dk<?BI#H
GO 7Vsp<s9bj
7、日志清除 A$3Rbn}"
SET NOCOUNT ON IO)#O<
DECLARE @LogicalFileName sysname, o(oOB
@MaxMinutes INT, a3<:F2=~\
@NewSize INT @2/|rq
USE tablename -- 要操作的数据库名 OIL8'xY.w
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uD>=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >4jE[$p]"
@NewSize = 1 -- 你想设定的日志文件的大小(M) W\k8f+Ke
-- Setup / initialize `,-mXxTNT
DECLARE @OriginalSize int ];LFv5"
SELECT @OriginalSize = size 0mujf
FROM sysfiles /@k#tdj
WHERE name = @LogicalFileName @wgd
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]~I+d/k
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ~_vSMX
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ztg_='n
FROM sysfiles \~ChbPnc
WHERE name = @LogicalFileName \"oZ\_
CREATE TABLE DummyTrans x{SlJ%V
(DummyColumn char (8000) not null) x_nwD"
DECLARE @Counter INT, WJOoDS!i
@StartTime DATETIME, (MI>7| ';
@TruncLog VARCHAR(255) )"pvF8JR%3
SELECT @StartTime = GETDATE(), R~4X?@ZB
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Q!;syJBb.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 1j$\ 48Z
EXEC (@TruncLog) O`9c!_lis
-- Wrap the log if necessary. gHLI>ew*QR
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9p qsr~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Bi:lC5d5?
AND (@OriginalSize * 8 /1024) > @NewSize din,yHu~
BEGIN -- Outer loop. Bzrnmz5S
SELECT @Counter = 0 3T)rJEN A
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Wr%ov6:
BEGIN -- update f\<r1
INSERT DummyTrans VALUES ('Fill Log') RJ{$`d
DELETE DummyTrans MqnUym
SELECT @Counter = @Counter + 1 0I)$!1~O)
END l~rj7f;
EXEC (@TruncLog) {h@\C|nF
END c4Zpt%:}h
SELECT 'Final Size of ' + db_name() + ' LOG is ' + K:a8}w>Up
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + sQa;l]O:NC
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [34N/;5
FROM sysfiles Cf=H~&`Z
WHERE name = @LogicalFileName [i`
DROP TABLE DummyTrans LpU}.
SET NOCOUNT OFF V:kRr cX
8、说明:更改某个表 .J)TIc__|A
exec sp_changeobjectowner 'tablename','dbo' T;/GHC`{Y
9、存储更改全部表 |#@7$#j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?8-!hU@QC
@OldOwner as NVARCHAR(128), 'q-q4QCB
@NewOwner as NVARCHAR(128) zl@^[km{
AS Y[6T7eZ0g
DECLARE @Name as NVARCHAR(128) J,yKO(}<C
DECLARE @Owner as NVARCHAR(128) (`.OS)&
DECLARE @OwnerName as NVARCHAR(128) (' 5?-
DECLARE curObject CURSOR FOR bQt:=>
select 'Name' = name, R+M =)Z
'Owner' = user_name(uid) 32[}@f2q
from sysobjects KdR4<qVV}
where user_name(uid)=@OldOwner h=7q;-@7
order by name 5l6/5
OPEN curObject qNQ54#
FETCH NEXT FROM curObject INTO @Name, @Owner ST*h{:u&A
WHILE(@@FETCH_STATUS=0) );gY8UL^
BEGIN Y<xqws
if @Owner=@OldOwner S/'0czDMW
begin a;HAuy`M x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !%G]~
exec sp_changeobjectowner @OwnerName, @NewOwner 7Jf~Bn
end j,M$l mR')
-- select @name,@NewOwner,@OldOwner %e E^Y<@g
FETCH NEXT FROM curObject INTO @Name, @Owner |h]V9=
END fg^25g'_
close curObject ZRagM'K
deallocate curObject
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GO pLB2! +
10、SQL SERVER中直接循环写入数据
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declare @i int d05xn7%!{
set @i=1 ,Xn2xOP
while @i<30 }%_|k^t
begin Zhq_ pus"a
insert into test (userid) values(@i) $D^\[^S
set @i=@i+1 P8d
end +~^S'6yB
小记存储过程中经常用到的本周,本月,本年函数 n[3z_QI
Dateadd(wk,datediff(wk,0,getdate()),-1) ,9P-<P
Dateadd(wk,datediff(wk,0,getdate()),6) U**8^:*y#:
Dateadd(mm,datediff(mm,0,getdate()),0) uY&1[(Pb
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /f3/}x!po
Dateadd(yy,datediff(yy,0,getdate()),0) 2LwJ%!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ]@&X*~c^Z
上面的SQL代码只是一个时间段 DK IH{:L7
Dateadd(wk,datediff(wk,0,getdate()),-1) Ei4^__g\'
Dateadd(wk,datediff(wk,0,getdate()),6) <7^|@L
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就是表示本周时间段. %Rk|B`ST
下面的SQL的条件部分,就是查询时间段在本周范围内的: $Ll9ak}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) =l`)b
而在存储过程中 NI V}hf YF
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Pd91<L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) z#tIa