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。 k]^ya?O]p
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一、基础 pp@B]We
1、说明:创建数据库 Ni%@bU $
CREATE DATABASE database-name ?20R\
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2、说明:删除数据库 $7ix(WL<%
drop database dbname lD, ~%
3、说明:备份sql server "vT$?IoEV
--- 创建 备份数据的 device
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USE master i(OeE"YA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 6B%
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--- 开始 备份 G%,
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BACKUP DATABASE pubs TO testBack z[ 'G"yCi
4、说明:创建新表 $PI9vyS
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2wDDVUwy B
根据已有的表创建新表: + ~5P7dh6
A:create table tab_new like tab_old (使用旧表创建新表) YaL:6[6
B:create table tab_new as select col1,col2... from tab_old definition only OScqf]H
5、说明:删除新表 (Q @'fb9z
drop table tabname x$bUd 9
6、说明:增加一个列 aL`wz !
Alter table tabname add column col type .c:h!-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。 3kk^hvB+f
7、说明:添加主键: Alter table tabname add primary key(col) FUlhEH
说明:删除主键: Alter table tabname drop primary key(col) Ibu9AwPm
8、说明:创建索引:create [unique] index idxname on tabname(col....) {~uTi>U
删除索引:drop index idxname d=n{Wn{C
注:索引是不可更改的,想更改必须删除重新建。 b$%Kv(
9、说明:创建视图:create view viewname as select statement E4>}O;m0
删除视图:drop view viewname !_QT{H
10、说明:几个简单的基本的sql语句 77y+ik
选择:select * from table1 where 范围 N_S~&(I|
插入:insert into table1(field1,field2) values(value1,value2) _ziSH 3(
删除:delete from table1 where 范围 .c~z^6x
更新:update table1 set field1=value1 where 范围 D/~1?p
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! K!.t}s.t
排序:select * from table1 order by field1,field2 [desc] q*|Alrm
总数:select count as totalcount from table1 EFljUT?&
求和:select sum(field1) as sumvalue from table1 $B_%MfI
平均:select avg(field1) as avgvalue from table1 gua7<z6=eh
最大:select max(field1) as maxvalue from table1 (ie%zrhS
最小:select min(field1) as minvalue from table1 {wsJ1v8!
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11、说明:几个高级查询运算词 '"\'<>Be
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A: UNION 运算符 =JgR c7
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 R ZQH#+*t}
B: EXCEPT 运算符 80_w_i +
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 j6Sg~nRh
C: INTERSECT 运算符 <+-n
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 z<mN-1PM7&
注:使用运算词的几个查询结果行必须是一致的。 ]X77?Zz9
12、说明:使用外连接 Btm_S\1
A、left outer join: DKu$u ]Z
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。 'QxJU$
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 H@Ot77(*
B:right outer join: fn=A_
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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。 ,LN^Zx*
C:full outer join: w5{l-Z
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。 d+,!p8Q
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二、提升 "n`z`{<n
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <<CWN(hQWO
法一:select * into b from a where 1<>1 j&_>_*.y
法二:select top 0 * into b from a } `Ya;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7/51_=%kR
insert into b(a, b, c) select d,e,f from b; P1T{5u!T
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) $x+7.%1m)~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 NWvIwt{
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _<FUS'"
4、说明:子查询(表名1:a 表名2:b) h=gtuaR4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 8K-P]]
5、说明:显示文章、提交人和最后回复时间 k]5tU\;Yw
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ]6[+tpx
6、说明:外连接查询(表名1:a 表名2:b) sdg2^] |
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #gO[di0WhC
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; xh$yXP0/
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 wCg7JW#
select * from table1 where time between time1 and time2 W/xPVmnV
select a,b,c, from table1 where a not between 数值1 and 数值2 S-q"'5>
9、说明:in 的使用方法 69)"T{7
select * from table1 where a [not] in ('值1','值2','值4','值6') ZxSFElDD]E
10、说明:两张关联表,删除主表中已经在副表中没有的信息 <tFq^qB
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) (,#m+
11、说明:四表联查问题: a;Y:UwD9*
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 ..... &RARK8^
12、说明:日程安排提前五分钟提醒 1Ub=RyB
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 9QXsbd6
13、说明:一条sql 语句搞定数据库分页 T?m@`"L,
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 *>:phs~r{
14、说明:前10条记录 8Iw)]}T'
select top 10 * form table1 where 范围 {+hABusq
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.) .=J- !{z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ocW~I3
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 XV]xym~
(select a from tableA ) except (select a from tableB) except (select a from tableC) 8+}rm6Y+
17、说明:随机取出10条数据 <3BGW?=WP
select top 10 * from tablename order by newid() l3>e-kP
18、说明:随机选择记录 x0JW
select newid() # euG$(
19、说明:删除重复记录 `x/i1^/_@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) x>Q% hl
20、说明:列出数据库里所有的表名 'Xj^cX
select name from sysobjects where type='U' d=qVIpZ
21、说明:列出表里的所有的 PHqg~q;*
select name from syscolumns where id=object_id('TableName') J.R\h!
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 6384$mT,S
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 F +(S-Qk1
显示结果: .ZF%$H
type vender pcs \{:A&X~\!
电脑 A 1 jDb\4QyC
电脑 A 1 7WS$fUBi
光盘 B 2 v{t
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光盘 A 2 re[5lFQ~Z
手机 B 3 wrgB =o
手机 C 3 2}pZyS
23、说明:初始化表table1 BYEZ[cM
TRUNCATE TABLE table1 JS^DyBXc
24、说明:选择从10到15的记录 G`O*AQ}[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |YROxY"ML
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三、技巧 4jebx
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1、1=1,1=2的使用,在SQL语句组合时用的较多 k-=lt\?
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6R<+_e+v
如: wB0vpt5f
if @strWhere !='' \z.bORy
begin ~:7y!=8#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R)JH D7
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end ub~ t}
else ^.8~}TT-U
begin z~vcwiYAP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' GWuKDq
end G)I`
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我们可以直接写成 }6-olVg
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m8{8r>6*
2、收缩数据库 N s0,Z#Z+
--重建索引 "ymR8y'
DBCC REINDEX 5s3QN{h8
DBCC INDEXDEFRAG 4%~*}
--收缩数据和日志 >4luZnWMI
DBCC SHRINKDB XN Uw
DBCC SHRINKFILE
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3、压缩数据库 Itr4Pr
dbcc shrinkdatabase(dbname) =hvPq@C%
4、转移数据库给新用户以已存在用户权限 9n\>Yieu
exec sp_change_users_login 'update_one','newname','oldname' 2sIt~ Gn
go PY7H0\S)
5、检查备份集 \f^xlX3&`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &mVClq
6、修复数据库 <DR|r
ALTER DATABASE [dvbbs] SET SINGLE_USER MZQDFuvDxZ
GO W.[!Q`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK W..*!UGl
GO ^@* `vz^_
ALTER DATABASE [dvbbs] SET MULTI_USER mTtaqo_Bh
GO 46D`h!7L
7、日志清除 u~M$<|;
SET NOCOUNT ON H~s8M
DECLARE @LogicalFileName sysname, /A,w{09G
@MaxMinutes INT, .
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@NewSize INT rN|=cn
USE tablename -- 要操作的数据库名 p=nbsS~":
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5Z_C(5)/Y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zTB&Wlt
@NewSize = 1 -- 你想设定的日志文件的大小(M) u>9` ?O44
-- Setup / initialize Vu.=,G
DECLARE @OriginalSize int vq(#Ih2
SELECT @OriginalSize = size L#K`F8Wi=
FROM sysfiles <">epbV6
WHERE name = @LogicalFileName C3W4:kbau
SELECT 'Original Size of ' + db_name() + ' LOG is ' + kR97)}Y
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + dX/7n=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Oe\(=R
FROM sysfiles *z69ti/
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WHERE name = @LogicalFileName tE=09J%z
CREATE TABLE DummyTrans 2)\->$Q(H
(DummyColumn char (8000) not null) xAd@.^
DECLARE @Counter INT, J/e]
@StartTime DATETIME, Wx]Xa]-
@TruncLog VARCHAR(255) ]Pe>T&
SELECT @StartTime = GETDATE(), :po6%}hn
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;:
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) =U*D.p*%f
EXEC (@TruncLog) i#b /.oa
-- Wrap the log if necessary. a-|pSe*rx
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired k/{WlLN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) \7b, Mz!
AND (@OriginalSize * 8 /1024) > @NewSize [k%hl`}
BEGIN -- Outer loop. 3E;@.jD
SELECT @Counter = 0 KHZ[drb6$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) d]s^?=gM
BEGIN -- update asYk#;z\"
INSERT DummyTrans VALUES ('Fill Log') ~;CNWJtcf(
DELETE DummyTrans \ZADY.ha
SELECT @Counter = @Counter + 1 q&z'S
END oB5\^V$
EXEC (@TruncLog) Ph""[0n%o
END O>pX(DS
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3ArHaAv{y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _N|%i J5
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Ga02Zk
FROM sysfiles #<[&Lw
WHERE name = @LogicalFileName !0?o3,of-
DROP TABLE DummyTrans ^7+;XUyg
SET NOCOUNT OFF fdKE1,;
8、说明:更改某个表 +_fFRyu>
exec sp_changeobjectowner 'tablename','dbo' #d,)Qe[
9、存储更改全部表 ![K\)7 iKo
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch JS ^Cc
@OldOwner as NVARCHAR(128), n-8/CBEH(
@NewOwner as NVARCHAR(128) %z@ Z^Jv
AS b3-j2`#
DECLARE @Name as NVARCHAR(128) +7w5m
DECLARE @Owner as NVARCHAR(128) m0;j1-t
DECLARE @OwnerName as NVARCHAR(128) Lp:VU-S
DECLARE curObject CURSOR FOR xS_;p9{E
select 'Name' = name, ' F.^ 8/>
'Owner' = user_name(uid) ;=0mL,
from sysobjects W;I{4ed6
where user_name(uid)=@OldOwner gNP1UH4m
order by name Z(|$[GZP[
OPEN curObject 1+$F= M~
FETCH NEXT FROM curObject INTO @Name, @Owner WRu(F54Sk
WHILE(@@FETCH_STATUS=0) bgBvzV&'8
BEGIN QD!NV*
if @Owner=@OldOwner 9dA+#;?
begin <rgK}&q
set @OwnerName = @OldOwner + '.' + rtrim(@Name)
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exec sp_changeobjectowner @OwnerName, @NewOwner d)-ZL*o
end E{ c+`>CY
-- select @name,@NewOwner,@OldOwner HL"c yxe
FETCH NEXT FROM curObject INTO @Name, @Owner !Q|a R
END -&7?!<f
close curObject UAXp;W`
deallocate curObject *B!Ox}CI.L
GO w>f.@luO4
10、SQL SERVER中直接循环写入数据 C <:g"F:k
declare @i int lfM vNv
set @i=1 KDEyVYO:
while @i<30 n~yHt/T
begin cy,6^d
insert into test (userid) values(@i)
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set @i=@i+1 :1 qLRr
end
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小记存储过程中经常用到的本周,本月,本年函数 ?1\I/'E9
Dateadd(wk,datediff(wk,0,getdate()),-1) 3v_j*wy
Dateadd(wk,datediff(wk,0,getdate()),6) /Q@4HV
Dateadd(mm,datediff(mm,0,getdate()),0) (LTu=1
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 8m' f8.x
Dateadd(yy,datediff(yy,0,getdate()),0) qc,E azmU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9~Sa7P
上面的SQL代码只是一个时间段 agwbjkU/
Dateadd(wk,datediff(wk,0,getdate()),-1) 7WmLC
Dateadd(wk,datediff(wk,0,getdate()),6) H][TH2H1
就是表示本周时间段. wT!?.Y)aj
下面的SQL的条件部分,就是查询时间段在本周范围内的: `uPO+2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) xL_QTj
而在存储过程中 wry`2_c
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ."dT6u E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) OAq-(_H