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:<3d]L
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一、基础 t[ocp;Q
1、说明:创建数据库 T mE4p
CREATE DATABASE database-name !h(0b*FUJ
2、说明:删除数据库
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drop database dbname ~?+m=\
3、说明:备份sql server ~i#xjD5
--- 创建 备份数据的 device m;1e xa
USE master o*BI^4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' I<-"J^2
--- 开始 备份 u<2sb;a
BACKUP DATABASE pubs TO testBack gZSi\m>
4、说明:创建新表 OB@t(KNx*P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) D4-U[l+K>
根据已有的表创建新表: -iX!F~qS,
A:create table tab_new like tab_old (使用旧表创建新表) L, GtIZkE
B:create table tab_new as select col1,col2... from tab_old definition only
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5、说明:删除新表 y_r6T
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drop table tabname X*):N]
6、说明:增加一个列 }#^F'%zf
Alter table tabname add column col type a-5$GvG
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。 Db:WAjU
7、说明:添加主键: Alter table tabname add primary key(col) haK5Oe/cE
说明:删除主键: Alter table tabname drop primary key(col) IsL/p3|
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9xp
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删除索引:drop index idxname |?W
注:索引是不可更改的,想更改必须删除重新建。 O:R{4Q*5
9、说明:创建视图:create view viewname as select statement $QnfpM%+=
删除视图:drop view viewname 0P
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10、说明:几个简单的基本的sql语句 <p
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选择:select * from table1 where 范围 g5\B- 3{
插入:insert into table1(field1,field2) values(value1,value2) \H12~=p`B
删除:delete from table1 where 范围 )ISTb
更新:update table1 set field1=value1 where 范围 8R D)yRJ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! pU/.|Sh
排序:select * from table1 order by field1,field2 [desc] >GRuS\B
总数:select count as totalcount from table1 %c{)'X
求和:select sum(field1) as sumvalue from table1 K.zs;^
平均:select avg(field1) as avgvalue from table1 Z:Am\7 I
最大:select max(field1) as maxvalue from table1 KgSxF#
最小:select min(field1) as minvalue from table1 !!>G{
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11、说明:几个高级查询运算词 [ RuY'
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A: UNION 运算符 @SXgaWr
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。 gH.^NO5\'
B: EXCEPT 运算符 rP_)*)
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。 J6P
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C: INTERSECT 运算符 q;JQs:U!
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。 ;hDr+&J|
注:使用运算词的几个查询结果行必须是一致的。 C(hg"_W ou
12、说明:使用外连接 + k:?;ZG
A、left outer join: ?^p8]Va%
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。 D._r@~o
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 ks4
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B:right outer join: n4,J#h/
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。 1)ne-e
C:full outer join: #Xly5J
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。 `6su_8Hno
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二、提升 (H^o8J
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) LPF?\mf ^4
法一:select * into b from a where 1<>1
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法二:select top 0 * into b from a H;ib3?
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 6 H.Da]hk
insert into b(a, b, c) select d,e,f from b; :8
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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) Nx'j+>bz>y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Cv33?l-8%_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *^()el,d
4、说明:子查询(表名1:a 表名2:b) ]ghPbS@
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) ^lj>v}4fkW
5、说明:显示文章、提交人和最后回复时间 Y.J$f<[R
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~~mQ
6、说明:外连接查询(表名1:a 表名2:b) (z{xd
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *1Q?~
7、说明:在线视图查询(表名1:a ) GYO"1PM
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9:s!#FYFM
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 ;{RQ+ZX'[
select * from table1 where time between time1 and time2 db|$7]!w
select a,b,c, from table1 where a not between 数值1 and 数值2 AaVlNjB
9、说明:in 的使用方法 <LY+"
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select * from table1 where a [not] in ('值1','值2','值4','值6') /FY_LM
10、说明:两张关联表,删除主表中已经在副表中没有的信息 00+5a
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) k$c!J'qL&
11、说明:四表联查问题: 5B6:pH6e
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 ..... (B5G?cB9
12、说明:日程安排提前五分钟提醒 L\I/2aiE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ~MF. M8
13、说明:一条sql 语句搞定数据库分页 ]LjW,b"
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 Re_.<_$
14、说明:前10条记录 t|%ul6{gz
select top 10 * form table1 where 范围 PH.v3
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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.) Zlhr0itf
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) aoN[mV'
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 l]gfT&
(select a from tableA ) except (select a from tableB) except (select a from tableC) sXA=KD8
17、说明:随机取出10条数据 GU`2I/R
select top 10 * from tablename order by newid() lKcnM3n
18、说明:随机选择记录 XOMWqQr|
select newid() =
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19、说明:删除重复记录 -[z;y73]t
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wuCODz@~
20、说明:列出数据库里所有的表名 t [f]
select name from sysobjects where type='U' #"l=Lv
21、说明:列出表里的所有的 %|Vq"MW,I
select name from syscolumns where id=object_id('TableName') 1ARIZ;H
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。 ^Ue>T8
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 uP:'e8
显示结果: f|!zjX`
type vender pcs 7-)KTBFL
电脑 A 1 ~<-i7uM
电脑 A 1 Gwe9<
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光盘 B 2 zK v}J
光盘 A 2 }/|1"D
手机 B 3 <#sK~G
手机 C 3 x\WKsc
23、说明:初始化表table1 ``{xm1GK
TRUNCATE TABLE table1 "Z
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24、说明:选择从10到15的记录 V0>,Kxk
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >
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三、技巧 raCxHY
1、1=1,1=2的使用,在SQL语句组合时用的较多 B^Vb=* QRo
"where 1=1" 是表示选择全部 "where 1=2"全部不选, y7JJ[:~~
如: SyI#Q[f'_
if @strWhere !='' 74_ji!
begin e([}dz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ad[-YT
end xpae0vw
else "b qB@)
begin bTJ7RqL
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;TYkJH"
end ~ ~&M&Fe
我们可以直接写成 k2~j:&p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 0=NB[eG
2、收缩数据库 PM{kiz^
--重建索引 d4/ZOj+%
DBCC REINDEX #-{4F?DA]y
DBCC INDEXDEFRAG b$hQB090
--收缩数据和日志 tlE+G@|^
DBCC SHRINKDB wml`3$"cf
DBCC SHRINKFILE s<:J(gD
3、压缩数据库 k7? (IU
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 u?!p[y6
exec sp_change_users_login 'update_one','newname','oldname' cYK3>p
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go TWMD f
5、检查备份集 278
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' SKGYmleR
6、修复数据库 vq|W&
ALTER DATABASE [dvbbs] SET SINGLE_USER )l^w _;
GO 1r$q $\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO DF<_Ns!
ALTER DATABASE [dvbbs] SET MULTI_USER YkTEAI|i
GO _ 95V"h
7、日志清除 /IODRso/!
SET NOCOUNT ON ^XV$J-
DECLARE @LogicalFileName sysname, ^j@,N&W:lG
@MaxMinutes INT, <S<(wFE@4
@NewSize INT @#nB]qV:e
USE tablename -- 要操作的数据库名 h/d&P
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uCx\Bt"VI
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Pt E>08
@NewSize = 1 -- 你想设定的日志文件的大小(M) R ~#\gMs
-- Setup / initialize f5AK@]4G
DECLARE @OriginalSize int 7yK
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SELECT @OriginalSize = size 5E$)Ip
FROM sysfiles L0}"H
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WHERE name = @LogicalFileName #,Rmu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + w _n)*he)z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + z"|^Y|`m
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tJc9R2
FROM sysfiles 94Z~]C
WHERE name = @LogicalFileName C]82Mt
CREATE TABLE DummyTrans Jjv,
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(DummyColumn char (8000) not null) 9M<{@<]dm
DECLARE @Counter INT, d+$a5 [^9
@StartTime DATETIME, bX8Bn0#a+
@TruncLog VARCHAR(255) +`zM^'^$
SELECT @StartTime = GETDATE(), -3A#a_fu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &{99Owqg
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U)2\=%8
EXEC (@TruncLog) .Um.dXBYU
-- Wrap the log if necessary.
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired SBs_rhe
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) C,.$g>)MZK
AND (@OriginalSize * 8 /1024) > @NewSize t\X5B ]EZ
BEGIN -- Outer loop. C*=#=.~~{
SELECT @Counter = 0 p "u5wJ_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ?Yxk1Y4ig)
BEGIN -- update jT%k{"+>+?
INSERT DummyTrans VALUES ('Fill Log') i!9yN:m0
DELETE DummyTrans bmFnsqo
SELECT @Counter = @Counter + 1 >J+hu;I5
END )=#QTiJ
EXEC (@TruncLog) ~]3y667
END zGF_ c9X
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >zVj+
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + QOMh"wC3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {'T=&`&OF
FROM sysfiles UT%^!@u
WHERE name = @LogicalFileName 7*`cWT_X
DROP TABLE DummyTrans ki48]#p
SET NOCOUNT OFF 5^+>*z
8、说明:更改某个表 ;CD@RP{$n
exec sp_changeobjectowner 'tablename','dbo' gq!|0
9、存储更改全部表 1d,;e:=j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), > -OQk"o
@NewOwner as NVARCHAR(128) #}3$n/
AS ND77(I$3s
DECLARE @Name as NVARCHAR(128) se2ay_<F+
DECLARE @Owner as NVARCHAR(128) X2v|O3>/N
DECLARE @OwnerName as NVARCHAR(128) q,A; d^g
DECLARE curObject CURSOR FOR blEs!/A`
select 'Name' = name, "CX&2Xfe
'Owner' = user_name(uid) *%bQ p
from sysobjects jNBvy1
where user_name(uid)=@OldOwner EA8K*>'pv
order by name |p}qK
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OPEN curObject ^^1rjh1I
FETCH NEXT FROM curObject INTO @Name, @Owner QE1DTU
WHILE(@@FETCH_STATUS=0) eJlTCXeZ|
BEGIN 3!ZndWSHV
if @Owner=@OldOwner :=3Ty]e
begin }j;*7x8(
set @OwnerName = @OldOwner + '.' + rtrim(@Name) %#7Yr(&
exec sp_changeobjectowner @OwnerName, @NewOwner SjgjGJw
end (< gk<e*
-- select @name,@NewOwner,@OldOwner 6SJ
FETCH NEXT FROM curObject INTO @Name, @Owner H:TRJ.!w2
END ju~js
close curObject Sxa+"0d6
deallocate curObject W{B)c?G]
GO ~ (I'm[
10、SQL SERVER中直接循环写入数据 >,wm-4&E
declare @i int nO.RB#I$F
set @i=1 )2~Iqzc4
while @i<30 Ev+m+
begin Z:j6AF3;
insert into test (userid) values(@i) b=(?\
set @i=@i+1 QpbyC_:;$4
end '7Q5"M'
小记存储过程中经常用到的本周,本月,本年函数 z]:{ruvH
Dateadd(wk,datediff(wk,0,getdate()),-1) PZ06
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Dateadd(wk,datediff(wk,0,getdate()),6) .93B@u
Dateadd(mm,datediff(mm,0,getdate()),0) 2j*;1
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) d[eN#<
Dateadd(yy,datediff(yy,0,getdate()),0) 6HeZ<.d&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) oP vk ^H
上面的SQL代码只是一个时间段 '@t}8J
Dateadd(wk,datediff(wk,0,getdate()),-1) 2B Dz \
Dateadd(wk,datediff(wk,0,getdate()),6) 0Rgo#`7l
就是表示本周时间段. ='"DUQH|*
下面的SQL的条件部分,就是查询时间段在本周范围内的: HuzHXn)
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) `tZ m
而在存储过程中 csABfxib
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ay4E\=k
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9[31EiT