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。 "m$##X\
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一、基础 =+-UJo5
1、说明:创建数据库 6dr%;Wp
CREATE DATABASE database-name V*;(kEqj
2、说明:删除数据库 hp50J
drop database dbname QD&`^(X1p
3、说明:备份sql server
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--- 创建 备份数据的 device |Pax =oJ\M
USE master vkV0On
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?3`UbN:
--- 开始 备份 CJx|?yK2
BACKUP DATABASE pubs TO testBack U[-o> W#
4、说明:创建新表 vzAax k%
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]L.O8
根据已有的表创建新表: 9!\B6=r y4
A:create table tab_new like tab_old (使用旧表创建新表) r.&Vw|*>
B:create table tab_new as select col1,col2... from tab_old definition only yjX9oxhtL
5、说明:删除新表 3,3N^nSD
drop table tabname ',@3>T**
6、说明:增加一个列 FIhk@TKa
Alter table tabname add column col type 13=AW
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ;?iW%:_,
7、说明:添加主键: Alter table tabname add primary key(col) N/2T[s_&
说明:删除主键: Alter table tabname drop primary key(col) !>&o01i
8、说明:创建索引:create [unique] index idxname on tabname(col....) ]y'>=a|T
删除索引:drop index idxname w+|L+h3L7
注:索引是不可更改的,想更改必须删除重新建。 %)W2H^
9、说明:创建视图:create view viewname as select statement s~g *@K >+
删除视图:drop view viewname UKvW Jnz
10、说明:几个简单的基本的sql语句 F^BS/Yag
选择:select * from table1 where 范围 J/aC}}5D
插入:insert into table1(field1,field2) values(value1,value2) 7(8;to6(
删除:delete from table1 where 范围 i$G@R%
更新:update table1 set field1=value1 where 范围 ?Ep [M:,q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *vxk@`K~
排序:select * from table1 order by field1,field2 [desc] =s2*H8]
总数:select count as totalcount from table1 J=I:CD%
求和:select sum(field1) as sumvalue from table1 #OD/$f_
平均:select avg(field1) as avgvalue from table1 u|TeE\0
最大:select max(field1) as maxvalue from table1 )9`qG:b'
最小:select min(field1) as minvalue from table1 $|@@Qk/T
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11、说明:几个高级查询运算词 Be2DN5)
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A: UNION 运算符 kfY}S
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 .jE{ 3^
B: EXCEPT 运算符 Fj3a.'
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 q ^N7I@Y
C: INTERSECT 运算符 SsDmoEeB[
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ~Otoqu|
注:使用运算词的几个查询结果行必须是一致的。 @9RM9zK.q
12、说明:使用外连接 Ai?*s%8v
A、left outer join: 051E6-
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 '$(^W@M#6
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 WO>nIo5Y
B:right outer join: A[{yCn`tM
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。 h]}wp;Z
C:full outer join: T_5H&;a
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。 '4Bm;&6M
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二、提升 G}raA%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) i3mcx)d@H
法一:select * into b from a where 1<>1 %pL''R9VF
法二:select top 0 * into b from a :J&oX
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) yq\K)g*=
insert into b(a, b, c) select d,e,f from b; 16( QR-
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) H40p86@M
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6 V=9M:
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 2eY_%Y0
4、说明:子查询(表名1:a 表名2:b)
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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) MKi0jwJM
5、说明:显示文章、提交人和最后回复时间 } (73Syl#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?1
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6、说明:外连接查询(表名1:a 表名2:b) K?1W!fY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =X:Y,?
7、说明:在线视图查询(表名1:a ) ;dgp+
select * from (SELECT a,b,c FROM a) T where t.a > 1; @K!T,U
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 jm/`iXnMf
select * from table1 where time between time1 and time2 9qzHS~l
select a,b,c, from table1 where a not between 数值1 and 数值2 HQhM'x
9、说明:in 的使用方法 h3
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select * from table1 where a [not] in ('值1','值2','值4','值6') {cVEmvE8
10、说明:两张关联表,删除主表中已经在副表中没有的信息 "@0]G<H
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) f6>b|k~
11、说明:四表联查问题: UySZbmP48
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 ..... +',S]Edx
12、说明:日程安排提前五分钟提醒 FWgpnI\X|{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8'io$6d=
13、说明:一条sql 语句搞定数据库分页 k,+0u/I
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 JP[K;/
14、说明:前10条记录 )1`0PJoHE
select top 10 * form table1 where 范围 tl^9WG
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) `Eo.v#<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6mxfLlZ
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ]jp6k<KF
(select a from tableA ) except (select a from tableB) except (select a from tableC) sS'm!7*(3
17、说明:随机取出10条数据 56kI
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select top 10 * from tablename order by newid() Ean5b>\
18、说明:随机选择记录 d|Lj~x|
select newid() sWnLEw
19、说明:删除重复记录 z5*'{t)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) H8}oIA"b
20、说明:列出数据库里所有的表名 s
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select name from sysobjects where type='U' Si;H0uP O
21、说明:列出表里的所有的 -k"/X8
select name from syscolumns where id=object_id('TableName') *#+An<iT ;
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 Ry6@VQ"NLb
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >e5qv(y]
显示结果: wgGl[_)
type vender pcs )R1<N
电脑 A 1 \d`h/tHk
电脑 A 1 t&e{_|i#+
光盘 B 2 ~6LN6}~|.
光盘 A 2 e^1Twz3z
手机 B 3 ,/|T-Ka
手机 C 3 lA8`l>I
23、说明:初始化表table1 f
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TRUNCATE TABLE table1 }`m/bgtFX
24、说明:选择从10到15的记录 oE]QF.n#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc r$s Qf&=
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三、技巧 sdw(R#GE
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?hy&
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ,.FxIl]
如: }b.%Im<3R
if @strWhere !='' WCixKYq
begin -m~#Bq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0oIe>r
end {&1/V
else T1=fNF
begin q^<?]8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .U]-j\
end P71Lqy)5}A
我们可以直接写成 Y`a3tO=Pd
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere '?(% Zxw%&
2、收缩数据库 /f;~X"!
--重建索引 kMN~Y
DBCC REINDEX ePo}y])2
DBCC INDEXDEFRAG f(MO_Sj]
--收缩数据和日志 JDT`C2-Q
DBCC SHRINKDB BLD gt~h#
DBCC SHRINKFILE h(EhkCf
3、压缩数据库 m!HJj>GEo
dbcc shrinkdatabase(dbname) +ksVtG,
4、转移数据库给新用户以已存在用户权限 iGB}Il)
exec sp_change_users_login 'update_one','newname','oldname' E hMNap}5"
go DN:EB@
5、检查备份集 [` 7ThHX
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' f._ua>v,f
6、修复数据库 1p=]hC
ALTER DATABASE [dvbbs] SET SINGLE_USER oXF.1f/h
GO {R6ZKB
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Btcy)LRk
GO (<C3Vts))
ALTER DATABASE [dvbbs] SET MULTI_USER h~zT ydnH
GO *J`O"a
7、日志清除 ?&1!vz
SET NOCOUNT ON ~Z'?LV<t
DECLARE @LogicalFileName sysname, {R`[kt
@MaxMinutes INT, <wD-qT W
@NewSize INT 3(80:@|
USE tablename -- 要操作的数据库名 |&i<bqLw:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 d/~9&wLSb
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }@d @3
@NewSize = 1 -- 你想设定的日志文件的大小(M) 13x p_j
-- Setup / initialize L~N460
DECLARE @OriginalSize int =@~Y12o?%
SELECT @OriginalSize = size ysY*k` 5
FROM sysfiles fe_5LC"
WHERE name = @LogicalFileName ;;/{xvQ.1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4BpZJ~(p
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AFwdJte9e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' K[zVa
FROM sysfiles >i?oC^QM
WHERE name = @LogicalFileName FfT`;j
CREATE TABLE DummyTrans ^} >w<'0
(DummyColumn char (8000) not null) pOoEI+t
DECLARE @Counter INT, U| R_OLWAg
@StartTime DATETIME, !R`{ TbN
@TruncLog VARCHAR(255) 7WzxA=*#
SELECT @StartTime = GETDATE(), I{=Qtnlb
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' FGBbO\</
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >Cq<@$I2EB
EXEC (@TruncLog) _7_Y={4=`
-- Wrap the log if necessary. Y(Hs #Kn{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired M/`lM$98:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j8:\%|
AND (@OriginalSize * 8 /1024) > @NewSize >uEzw4w
BEGIN -- Outer loop. R[]Mdt<
SELECT @Counter = 0 )MT}+ai
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `r 4fm`<
BEGIN -- update Q\sK"~@3
INSERT DummyTrans VALUES ('Fill Log') Xne1gms
DELETE DummyTrans "qy,*{~
SELECT @Counter = @Counter + 1 4 s9LB
END jT;;/Fd3/
EXEC (@TruncLog) l,aay-E
END R`-S/C
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $M:*T.3
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )NT*bLRPQ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles _Y m2/3!
WHERE name = @LogicalFileName P@~yx#G
DROP TABLE DummyTrans +:/%3}`
SET NOCOUNT OFF -m#)B~)
8、说明:更改某个表 P16~Qj
exec sp_changeobjectowner 'tablename','dbo' + Vdpy(
9、存储更改全部表 Qn2&nD%zi
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch \a3+rNdj
@OldOwner as NVARCHAR(128), <9b&<K:
@NewOwner as NVARCHAR(128) */S_Icf
AS XQw9~$
DECLARE @Name as NVARCHAR(128) 4s
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DECLARE @Owner as NVARCHAR(128) 3Tm+g2w2V8
DECLARE @OwnerName as NVARCHAR(128) ~pky@O#b
DECLARE curObject CURSOR FOR %A0/1{(
select 'Name' = name, %J-GKpo/S
'Owner' = user_name(uid) -$Ih@2"6
from sysobjects fI|$K)K
where user_name(uid)=@OldOwner dqcL]e
order by name "d}Gp9+$VY
OPEN curObject llDkJ)\
FETCH NEXT FROM curObject INTO @Name, @Owner 9;If&uM
WHILE(@@FETCH_STATUS=0) G^@5H/)
BEGIN 1k^oS$UT
if @Owner=@OldOwner F((4U"
begin b\,+f n
set @OwnerName = @OldOwner + '.' + rtrim(@Name) U
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exec sp_changeobjectowner @OwnerName, @NewOwner i"=\d
end K:WDl;8(d
-- select @name,@NewOwner,@OldOwner tO&^>&;5
FETCH NEXT FROM curObject INTO @Name, @Owner DVeE1Q
END o5)<$P43
close curObject f%8C!W]Dm
deallocate curObject
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GO HK%7g
10、SQL SERVER中直接循环写入数据 IAyp 2
declare @i int 1B\WA8
set @i=1 u$`a7Lp,n
while @i<30 Rk8P
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begin wdoR%b{M
insert into test (userid) values(@i) \}G^\p6?M
set @i=@i+1 5Ynd c)Z
end _','9|
小记存储过程中经常用到的本周,本月,本年函数 2>59q$|
Dateadd(wk,datediff(wk,0,getdate()),-1) -ze J#B)C
Dateadd(wk,datediff(wk,0,getdate()),6) !TcJ)0
Dateadd(mm,datediff(mm,0,getdate()),0) Kf-JcBsrT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) iJ|uvPCE
Dateadd(yy,datediff(yy,0,getdate()),0) VS|2|n1<6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) $NO&YLS@
上面的SQL代码只是一个时间段 T6kdS]4-
Dateadd(wk,datediff(wk,0,getdate()),-1) @KUWxFak
Dateadd(wk,datediff(wk,0,getdate()),6) L4l!96]a
就是表示本周时间段. #,v{Ihn
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4`=mu}Y2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) @[v~y"tE}
而在存储过程中 H%lVl8oQ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) i{qgn%#}Y