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。 c=33O,_
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一、基础 ko6[Ej:TBo
1、说明:创建数据库 {~ 1
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CREATE DATABASE database-name s,-}}6WO
2、说明:删除数据库 /}nq?Vf
drop database dbname 7E;`1lh7
3、说明:备份sql server vGchKN~_
--- 创建 备份数据的 device l f_q6y
USE master q>[}JtXK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' (Ji=fh+
--- 开始 备份 SyIi*dH
BACKUP DATABASE pubs TO testBack :Jo[bm
4、说明:创建新表 _^`TG]F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `:
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根据已有的表创建新表: F{laA YE
A:create table tab_new like tab_old (使用旧表创建新表) ;n.SRy6
B:create table tab_new as select col1,col2... from tab_old definition only X 1}U
5、说明:删除新表 aEdc8i?
drop table tabname LknV47vd
6、说明:增加一个列 eOJ_L]y-
Alter table tabname add column col type T2 /u7<D-
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。 /@0
7、说明:添加主键: Alter table tabname add primary key(col) <"nF`'olV
说明:删除主键: Alter table tabname drop primary key(col) (>`S{L
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8、说明:创建索引:create [unique] index idxname on tabname(col....) ]s`cn}d
删除索引:drop index idxname lhB;jE
注:索引是不可更改的,想更改必须删除重新建。 + De-U.
9、说明:创建视图:create view viewname as select statement 1aoKf F(
删除视图:drop view viewname x/IAc6H~_8
10、说明:几个简单的基本的sql语句 F **/T
选择:select * from table1 where 范围 P7*?E*
插入:insert into table1(field1,field2) values(value1,value2) c!] yT0v&s
删除:delete from table1 where 范围 M>u84|`
更新:update table1 set field1=value1 where 范围 1HUe8m[#3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i7\MVI8
排序:select * from table1 order by field1,field2 [desc] .5iXOS0
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总数:select count as totalcount from table1 yH]w(z5Z
求和:select sum(field1) as sumvalue from table1 8r48+_y3u
平均:select avg(field1) as avgvalue from table1 0r]-Ltvl?}
最大:select max(field1) as maxvalue from table1 0[Z wtfL1
最小:select min(field1) as minvalue from table1 U\dLq&=V
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11、说明:几个高级查询运算词 I|_U|H!`
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A: UNION 运算符 L<p.2[3
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。 >z k6{kC
B: EXCEPT 运算符 wPaMYxO/
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 :xC1Ka%~
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。 l|fb;Giq=D
注:使用运算词的几个查询结果行必须是一致的。 s(y=u >
12、说明:使用外连接 Gg6<4T1
A、left outer join: CW?R7A/
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。 -"}nm!j /5
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 2cko
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B:right outer join: x{1S!A^
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。 |] ]Rp
C:full outer join: 6{H@VF<QY!
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。
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二、提升 fn Pej?f:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5wbR}`8
法一:select * into b from a where 1<>1 q=;U(,Y
法二:select top 0 * into b from a `]5 t'Ps
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7kmd.<
insert into b(a, b, c) select d,e,f from b; T5>'q;jM
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) sDjbvC0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 n(j5dN>]
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \6vr)1~N>
4、说明:子查询(表名1:a 表名2:b) -8z@FLUK-
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) W.?EjEx
5、说明:显示文章、提交人和最后回复时间 ~Q+J1S]Fs
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 3Cg0^~?6-
6、说明:外连接查询(表名1:a 表名2:b) _o{w<b&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c rM)#}eZK!
7、说明:在线视图查询(表名1:a ) 1j+RXb\<
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6<{SbE|G{
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 =A<a9@N}N
select * from table1 where time between time1 and time2 -x+K#T0Z
select a,b,c, from table1 where a not between 数值1 and 数值2 =|IY[2^
9、说明:in 的使用方法 4Vv$bbu+
select * from table1 where a [not] in ('值1','值2','值4','值6') W4]jx]
10、说明:两张关联表,删除主表中已经在副表中没有的信息 g.COKA
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) b21@iW
11、说明:四表联查问题: .]ZMxDZ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... /v7o!D1G
12、说明:日程安排提前五分钟提醒 no7Q%O9
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 A<[BR*n
13、说明:一条sql 语句搞定数据库分页 5XinZ~
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 o| 9Mj71
14、说明:前10条记录 sYd)r%%AU
select top 10 * form table1 where 范围 d1u6*&@lf
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 7xCm"jgP
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) r^;1Sm
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ~D_Wqr
(select a from tableA ) except (select a from tableB) except (select a from tableC) |[MtUWEW
17、说明:随机取出10条数据 A8 j$c ~
select top 10 * from tablename order by newid() {3K`yDF
18、说明:随机选择记录 /N=M9i\;
select newid() SD]rYIu+
19、说明:删除重复记录 y#-~L-J_R
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) q uiX"lV(
20、说明:列出数据库里所有的表名 >"pHk@AW K
select name from sysobjects where type='U' e{}vT$-
21、说明:列出表里的所有的 P@8S|#LpZ
select name from syscolumns where id=object_id('TableName') <MgC7S2I
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。 LmjGU[L,@
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 $mut v=IO
显示结果: V~S(cO[vj
type vender pcs D9higsN
电脑 A 1 ejlau#8"
电脑 A 1 ~~{+?v6B]
光盘 B 2 AQgm]ex<
光盘 A 2 t`'5|
手机 B 3 mZ#h p}\.
手机 C 3 b$=c(@]
23、说明:初始化表table1 -02.n}u>
TRUNCATE TABLE table1 ,W5!=\Gg(
24、说明:选择从10到15的记录 z;Dc#SZnO(
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KvtJtql;
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三、技巧 }/M`G]wT#
1、1=1,1=2的使用,在SQL语句组合时用的较多 U&u~i
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, :KBy(}V
如: gi<%: [jT
if @strWhere !='' <Eh_
begin WU{9lL=
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mEq>{l:
end ~o8x3`CoF
else 3(=QY)
begin h:{^&d
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _TjRvILC
end G!g];7PG(
我们可以直接写成 RBV*e9P%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere I4MZJAYk
2、收缩数据库 !'8jy_<9
--重建索引 eD0|6P;Ei
DBCC REINDEX 8eD/9PD=F
DBCC INDEXDEFRAG P7
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--收缩数据和日志 Q=F^Y f
DBCC SHRINKDB Gw?ueui<
DBCC SHRINKFILE -[xbGSj{
3、压缩数据库 /gq\.+'{
dbcc shrinkdatabase(dbname) "hLmwz|a
4、转移数据库给新用户以已存在用户权限 ~otV'= /my
exec sp_change_users_login 'update_one','newname','oldname' /9SNXjfbt
go 0"DS>:Ntk
5、检查备份集 |!*abc\`(`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (n4Uc308
6、修复数据库 &f<Ltdw
ALTER DATABASE [dvbbs] SET SINGLE_USER \x=!'
GO >W^)1E,Qh
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK EL;OYW(
GO ]vZ}4Xno
ALTER DATABASE [dvbbs] SET MULTI_USER & hv@ &
GO %QFeQ(b/(
7、日志清除 !c=EB`<*
SET NOCOUNT ON ]`TX%Qni
DECLARE @LogicalFileName sysname, 0oo*F
@MaxMinutes INT, e/F+Tf
@NewSize INT 6yhRcvJ}
USE tablename -- 要操作的数据库名 `{'h+v`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *2r(!fJP=^
@MaxMinutes = 10, -- Limit on time allowed to wrap log. tS6r4d%~=
@NewSize = 1 -- 你想设定的日志文件的大小(M) aIklAj)=
-- Setup / initialize Rj~y#m
DECLARE @OriginalSize int [A#>G4a<
SELECT @OriginalSize = size 7WEoyd
FROM sysfiles t[X,m]SX
WHERE name = @LogicalFileName Sbjc8V ut
SELECT 'Original Size of ' + db_name() + ' LOG is ' + PAs.T4Av^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R6qC0@*
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' BaOPtBYA:
FROM sysfiles 1JF>0ijU@
WHERE name = @LogicalFileName %oiA'hz;*
CREATE TABLE DummyTrans vz`r
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(DummyColumn char (8000) not null) @S?D}myD
DECLARE @Counter INT, J9XV:)Yv#
@StartTime DATETIME, yvV]|B@sO
@TruncLog VARCHAR(255) ?D=t:=
SELECT @StartTime = GETDATE(), r lXMrn
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' xqzB=0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) trM)&aQto
EXEC (@TruncLog) }Fb966 $
-- Wrap the log if necessary. <*5` TE0J
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired yI8
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Tizjh&*^
AND (@OriginalSize * 8 /1024) > @NewSize 3Qu Ft~@@
BEGIN -- Outer loop. yrV]I(Xe
SELECT @Counter = 0 7:X@lmBz=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) bXK$H=S Bz
BEGIN -- update 2hE+Om^n
INSERT DummyTrans VALUES ('Fill Log') UszR. Z
DELETE DummyTrans XMm(D!6
SELECT @Counter = @Counter + 1
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END +*KDtqZjk
EXEC (@TruncLog) x*0mmlCb
END BnIZ+fg=
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 0j2M< W#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lv\^@9r
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]M/*Beh
FROM sysfiles 6|ENDd[
WHERE name = @LogicalFileName l&6+ykQ
DROP TABLE DummyTrans =pn(56
SET NOCOUNT OFF }d 16xp
8、说明:更改某个表 n^k Uu2g|
exec sp_changeobjectowner 'tablename','dbo' q=_tjg
9、存储更改全部表 bT c'E#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch L+TM3*a*
@OldOwner as NVARCHAR(128), zq4)Uab*
@NewOwner as NVARCHAR(128) [C( >e0r
AS r+;AE N48
DECLARE @Name as NVARCHAR(128) JsbH'l
DECLARE @Owner as NVARCHAR(128) t$5)6zG
DECLARE @OwnerName as NVARCHAR(128) D8wZC'7
DECLARE curObject CURSOR FOR I>45xVA
select 'Name' = name, LKI2R_|n
'Owner' = user_name(uid) M;1B}x@
from sysobjects aXyg`CDv
where user_name(uid)=@OldOwner 5'"l0EuD
order by name L_ 2R3w
OPEN curObject :y(HOUB
FETCH NEXT FROM curObject INTO @Name, @Owner i T&Y9
WHILE(@@FETCH_STATUS=0) P>;u S
BEGIN 4dUr8]BkG
if @Owner=@OldOwner J5*( PxDF
begin E>w|i
set @OwnerName = @OldOwner + '.' + rtrim(@Name) eVujur$P
exec sp_changeobjectowner @OwnerName, @NewOwner r`!S*zK
end cS#m\O
-- select @name,@NewOwner,@OldOwner lr&O@
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FETCH NEXT FROM curObject INTO @Name, @Owner `~ {0
END =@ "'aCU/
close curObject * 2s(TW
deallocate curObject 0vi\o`**Mj
GO 1[H1l;
10、SQL SERVER中直接循环写入数据 EPL"H:o5%<
declare @i int iV8O<en&i
set @i=1 <[<]+r&*
while @i<30 \z)` pno
begin ~h6aTN
insert into test (userid) values(@i) lO dwH"
set @i=@i+1 TH#5j.uUs
end C9}m-N
小记存储过程中经常用到的本周,本月,本年函数 N.qS;%*o{e
Dateadd(wk,datediff(wk,0,getdate()),-1) y/yg-\/XF
Dateadd(wk,datediff(wk,0,getdate()),6) e6igx
Dateadd(mm,datediff(mm,0,getdate()),0) "ba>.h,#'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) #J)83
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) R|O."&CAB
上面的SQL代码只是一个时间段 ;mLbgiqQ J
Dateadd(wk,datediff(wk,0,getdate()),-1) +5IC-=ZB
Dateadd(wk,datediff(wk,0,getdate()),6) _!C'oG6s?
就是表示本周时间段. Zlf)
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下面的SQL的条件部分,就是查询时间段在本周范围内的: LFV',1+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M8iI e:{ c
而在存储过程中 Aq"<#:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 30nR2mB
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) a gM I$