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。 8+a<#?;
xO<-<sRA
0nz@O^*g(
一、基础 [l%fL9
1、说明:创建数据库 /B@%pq
CREATE DATABASE database-name +wW
2、说明:删除数据库 _@pf1d$
drop database dbname kqigFcz!Y
3、说明:备份sql server &@utAuI
--- 创建 备份数据的 device X,EYa>RSy_
USE master a/<pf\O
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' csX*XiDWm
--- 开始 备份 gQd=0"MV
BACKUP DATABASE pubs TO testBack d<GG(
4、说明:创建新表 q\t>D
_lU
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) *DCNu{6
根据已有的表创建新表: FR,#s^kF
A:create table tab_new like tab_old (使用旧表创建新表) sx<+ *Trl
B:create table tab_new as select col1,col2... from tab_old definition only zg Y*|{4Sl
5、说明:删除新表 0rJ\e
drop table tabname Ya&\ly
/i
6、说明:增加一个列 <6b\i5j
Alter table tabname add column col type V@n(v\F
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。 <fsn2[V:B%
7、说明:添加主键: Alter table tabname add primary key(col) iC|6roO!jk
说明:删除主键: Alter table tabname drop primary key(col) QjjJtKz
8、说明:创建索引:create [unique] index idxname on tabname(col....) Na 9l#
删除索引:drop index idxname $
lsRg:J
注:索引是不可更改的,想更改必须删除重新建。 .V 3X#t
9、说明:创建视图:create view viewname as select statement PP[)h,ZL*
删除视图:drop view viewname q8xc70: R
10、说明:几个简单的基本的sql语句 yCkW2p]s,K
选择:select * from table1 where 范围 %{~mk[d3
插入:insert into table1(field1,field2) values(value1,value2) aU.0dsq
删除:delete from table1 where 范围 zNr_W[
更新:update table1 set field1=value1 where 范围 <aSLm=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _h=<_Z
排序:select * from table1 order by field1,field2 [desc] AV[P QI
总数:select count as totalcount from table1 JIbzh?$aD
求和:select sum(field1) as sumvalue from table1 XJlDiBs9=Q
平均:select avg(field1) as avgvalue from table1 YNgR1:l
最大:select max(field1) as maxvalue from table1 9 CK\tx&
最小:select min(field1) as minvalue from table1 E0)mI)RW.
gvc'
$9%
v>y8s&/
@t;O"q'|
11、说明:几个高级查询运算词 ?9zoQ[
~?`9i>3W~
W`/jz/
A: UNION 运算符 j&[3Be'pQ
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 J'&B:PZObB
B: EXCEPT 运算符 !/Bw,y ri<
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Avv
C: INTERSECT 运算符 =Mu'+,dT
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ~0[G/A$]
注:使用运算词的几个查询结果行必须是一致的。 \/'#=q1
12、说明:使用外连接 X\p`pw$
A、left outer join: 3
!> L?
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。 o.A}``
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 t=W$'*P0}
B:right outer join: Ca5Sc, no
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 kJ#[UCqzM
C:full outer join: fJn3"D'
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 7\0|`{|R@
;!0.Kk
4
PD}SPOA`U3
二、提升 cGpN4|*rQ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =Qj+Ug'
法一:select * into b from a where 1<>1 n$m]58w
法二:select top 0 * into b from a r>Qyc
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) fD\^M{5f
insert into b(a, b, c) select d,e,f from b; ^aD/ .
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) N}}PlGp$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =hugnX<9
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 3<jAp#bE
4、说明:子查询(表名1:a 表名2:b) 1fO2)$Y
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) fUp|3bBE
5、说明:显示文章、提交人和最后回复时间 }/7.+yD
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CFkW@\]
6、说明:外连接查询(表名1:a 表名2:b) fbHWBb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ]U#[\ Z
7、说明:在线视图查询(表名1:a ) "S B%02
select * from (SELECT a,b,c FROM a) T where t.a > 1; *fQ?A|l!x
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 @;m@Luk
select * from table1 where time between time1 and time2 &3 XFgHo
select a,b,c, from table1 where a not between 数值1 and 数值2 ^T}}4I_Y
9、说明:in 的使用方法 8tT&BmT
select * from table1 where a [not] in ('值1','值2','值4','值6') GLaZN4`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 c>u>Pi;Z
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) eHR&N.2
11、说明:四表联查问题: j h1 bn
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 ..... Y @XkqvX
12、说明:日程安排提前五分钟提醒 B{OW}D$P#
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 V`R)#G>IH%
13、说明:一条sql 语句搞定数据库分页 e}](6"t`5
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 i3M?D}(Bs
14、说明:前10条记录 ]uStn
select top 10 * form table1 where 范围 AT%*
~tr
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) As6)_8w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Yhc6P%{Z^
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 M!&_qj&N,
(select a from tableA ) except (select a from tableB) except (select a from tableC) H IPcZ!p
17、说明:随机取出10条数据 IFC%%It5,
select top 10 * from tablename order by newid() 0.J1!RIK/
18、说明:随机选择记录 {FV,j.D
select newid() vB{;N
19、说明:删除重复记录 VVI8)h8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) fW5"4,
20、说明:列出数据库里所有的表名 !7mvyc!'!
select name from sysobjects where type='U' k\+y4F8$x
21、说明:列出表里的所有的 u@=+#q~/P
select name from syscolumns where id=object_id('TableName') Q*09E
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。 _XY`UZ
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 <K DH
显示结果: Nl=m'4@`
type vender pcs ]=?X*,'
电脑 A 1 PS_3Oq)
电脑 A 1 gtaV6sD
光盘 B 2 Qm35{^p+
光盘 A 2 G|QUujl
手机 B 3 #L@} .Giz
手机 C 3 pW*{Mx
23、说明:初始化表table1 vi[#?;pkF
TRUNCATE TABLE table1 1R'u v4e
24、说明:选择从10到15的记录 3:]{(@J
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc PZ
)XmCy"xx
pgz:F#>
klK-,J
三、技巧 ot|N;=ZKo
1、1=1,1=2的使用,在SQL语句组合时用的较多 MO));M)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Lf,CxZL5
如: 'L>&ZgLy
if @strWhere !='' rQu
begin +Fc ET
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~
V@xu{
end N`,7 FI}
else HZQDe&
begin Hk<X
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Tm%$J
end fs2mN1
我们可以直接写成 XPHQAo[(s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere r.^0!(d
2、收缩数据库 PtQQZ"ept
--重建索引 1KeJd&e
DBCC REINDEX egZyng
pB
DBCC INDEXDEFRAG V;>9&'Z3
--收缩数据和日志 L
Yh@ u1p
DBCC SHRINKDB #d}0}7ue
DBCC SHRINKFILE 4o1Q7
3、压缩数据库 :0
W6uFNOU
dbcc shrinkdatabase(dbname) >:w?qEaE
4、转移数据库给新用户以已存在用户权限 jgk{'_ j
exec sp_change_users_login 'update_one','newname','oldname' `FZ(#GDF
go K)<Wm,tON
5、检查备份集 b\SXZN)Be
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' { c v;w
6、修复数据库 gIV3n#-{L
ALTER DATABASE [dvbbs] SET SINGLE_USER :`:xP
GO RpHpMtvNo/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <MPeh&_3#
GO f|-
m ^/y
ALTER DATABASE [dvbbs] SET MULTI_USER /HB+ami,
GO (\Rwf}gyR
7、日志清除 C/mg46
v2W
SET NOCOUNT ON @MNl*~'$.[
DECLARE @LogicalFileName sysname, [MV`pF)x
@MaxMinutes INT, ry$tK"v/
@NewSize INT *hv=~A
$q
USE tablename -- 要操作的数据库名 _oQtk^fp
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [GtcaX{Zz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. +\+Uz!YS
@NewSize = 1 -- 你想设定的日志文件的大小(M) th5,HO~
-- Setup / initialize <'r0r/0g?
DECLARE @OriginalSize int Iv'RLM
SELECT @OriginalSize = size NY4!TOp
FROM sysfiles j`>?"1e@x
WHERE name = @LogicalFileName fUb1/-}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,]0S4h67
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + JaH*
rDs-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' l_^T&xq8
FROM sysfiles Oamv9RyDvC
WHERE name = @LogicalFileName 4 hL`=[AB
CREATE TABLE DummyTrans oHxGbvQc
(DummyColumn char (8000) not null) hNH.G(l0
DECLARE @Counter INT, ~Y\QGuT
@StartTime DATETIME, ^{),+S
@TruncLog VARCHAR(255) [yO=S0 e
SELECT @StartTime = GETDATE(), 3CA|5A.Pa
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' RxlszyE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Zw2jezP@t
EXEC (@TruncLog) PPUEkvH
W
-- Wrap the log if necessary. q $t&|{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired mG0L !5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aML#Z |n
AND (@OriginalSize * 8 /1024) > @NewSize '
be P
BEGIN -- Outer loop. u8|@|t
SELECT @Counter = 0 C>AcK#-x,{
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5iP8D<;o5
BEGIN -- update K|`+C1!
INSERT DummyTrans VALUES ('Fill Log') VMaS;)0f@
DELETE DummyTrans (F/HU"C
SELECT @Counter = @Counter + 1 P;j&kuW|zL
END :lgHL3yl
EXEC (@TruncLog) EC<5M5Lc
END $kD7y5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + EY
So=
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + BTOA &Ag
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0Xp
nbB~~I
FROM sysfiles %_>Tcm=
WHERE name = @LogicalFileName 1#/6r :
DROP TABLE DummyTrans g+e:@@ug
SET NOCOUNT OFF +H41]W6
8、说明:更改某个表 @XeEpDn]
exec sp_changeobjectowner 'tablename','dbo' DNmb[
9、存储更改全部表 $"/UK3|d
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch DLU[<!C
@OldOwner as NVARCHAR(128), VK9Q?nu
@NewOwner as NVARCHAR(128) JRD8Lz]Q3
AS UMT\Q6p
DECLARE @Name as NVARCHAR(128) k}X[u8A
DECLARE @Owner as NVARCHAR(128) xM%
pvx.'L
DECLARE @OwnerName as NVARCHAR(128) 9H>BWjS
DECLARE curObject CURSOR FOR g8KY`MBnC&
select 'Name' = name, ,g%o
'Owner' = user_name(uid) w-r_H!-
from sysobjects Ft3I>=f{
where user_name(uid)=@OldOwner BlL|s=dlQV
order by name 8Bj4_!g
OPEN curObject HC?0Lj
FETCH NEXT FROM curObject INTO @Name, @Owner P= e4lF.
WHILE(@@FETCH_STATUS=0) 'c#IMlv
BEGIN ,E%1Uq"
if @Owner=@OldOwner 9e]'OKL+
begin o\&~CW~@~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) `(3SfQ-
exec sp_changeobjectowner @OwnerName, @NewOwner q1STRYb
end aQga3;S!
-- select @name,@NewOwner,@OldOwner %?Rs*-F.~1
FETCH NEXT FROM curObject INTO @Name, @Owner e]>/H8
END e$HQuA~Q;
close curObject kQy&I3
deallocate curObject CF\R<rF<VS
GO :"V ujvFX
10、SQL SERVER中直接循环写入数据 D@#0 dDT
declare @i int XjxPIdX_H
set @i=1 >jv\Qh
while @i<30 <8f(eP\*F
begin u %'y_C3
insert into test (userid) values(@i) QGXQ {
set @i=@i+1 vmvFBzLR
end `v~!H\q
小记存储过程中经常用到的本周,本月,本年函数 $Y6 3!*
Dateadd(wk,datediff(wk,0,getdate()),-1) V`by*s
Dateadd(wk,datediff(wk,0,getdate()),6) #XcU{5Qm5
Dateadd(mm,datediff(mm,0,getdate()),0) -/zp&*0gcx
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <>]1Y$^Y
Dateadd(yy,datediff(yy,0,getdate()),0) te)n{K",
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8`*`nQhWa
上面的SQL代码只是一个时间段 \2j|=S6
Dateadd(wk,datediff(wk,0,getdate()),-1) wrabyRjK
Dateadd(wk,datediff(wk,0,getdate()),6) ka#K
[qI
就是表示本周时间段. t}VwVf<K
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6%E~p0)i%
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) nx B32
而在存储过程中 Q{[@`bZB
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Lbsr_*4t
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9^au$KoU