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。 xe/(
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一、基础 >}(CEzc8
1、说明:创建数据库 J,b&XD@m
CREATE DATABASE database-name xW92ch+t
2、说明:删除数据库 znJ'iVf
drop database dbname {d?$m*YR3`
3、说明:备份sql server 1bGopi/
--- 创建 备份数据的 device GguFo+YeZ
USE master 52o x`t|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^iQn'++Q
--- 开始 备份 t(="h6i
BACKUP DATABASE pubs TO testBack aF7nvu*N
4、说明:创建新表 ak:c rrkx
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 7'OtruJ
根据已有的表创建新表: ,m,)I
A:create table tab_new like tab_old (使用旧表创建新表) q 4V7
B:create table tab_new as select col1,col2... from tab_old definition only vf8\i-U=
5、说明:删除新表 6m6zA/
drop table tabname <8,cuX\
6、说明:增加一个列 I* VCpaA
Alter table tabname add column col type a')|1DnR
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 cV`E>w=D0
7、说明:添加主键: Alter table tabname add primary key(col) RQMEBsI}
说明:删除主键: Alter table tabname drop primary key(col) JMTvSXr
8、说明:创建索引:create [unique] index idxname on tabname(col....) n8.kE)?
删除索引:drop index idxname SXt{k<|
注:索引是不可更改的,想更改必须删除重新建。 KoS*0U<g6
9、说明:创建视图:create view viewname as select statement [d* ~@P
删除视图:drop view viewname _v*
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10、说明:几个简单的基本的sql语句 v!%5&: c3
选择:select * from table1 where 范围 %TsPyiYl
插入:insert into table1(field1,field2) values(value1,value2) s@fTj$h
删除:delete from table1 where 范围 Wa?; ^T
更新:update table1 set field1=value1 where 范围 Yq/.-4y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g(#f:"
排序:select * from table1 order by field1,field2 [desc] l&}y/t4%
总数:select count as totalcount from table1 z)uuxNv[R
求和:select sum(field1) as sumvalue from table1 uPniLx\t:
平均:select avg(field1) as avgvalue from table1 Y[ N^p#t{
最大:select max(field1) as maxvalue from table1 +S=Rn,
最小:select min(field1) as minvalue from table1 vVE7fq3
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11、说明:几个高级查询运算词 \w'*z&`W9
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A: UNION 运算符 gkHNRAL
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。 cCR+D.F
B: EXCEPT 运算符 m XXt'_"
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。 k#5}\w!
C: INTERSECT 运算符 c5mZG7-
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。 ~(]0k.\
注:使用运算词的几个查询结果行必须是一致的。 #Z5}2soA
12、说明:使用外连接 Iuh/I +[7
A、left outer join: C{d7J'Avk
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。 u!:z.RH8n
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 aj}(E+
B:right outer join: ek
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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。 |`jjHuQ;
C:full outer join: 5[Pr|AY
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。 l{D'uI[&
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二、提升 SvR7eC
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) uB7 V?A
法一:select * into b from a where 1<>1 bb
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法二:select top 0 * into b from a %sRUh0AL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) N;+[`l
insert into b(a, b, c) select d,e,f from b; [{X^c.8G)
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) ?:Bv
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )IJQeC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *FJZiPy
4、说明:子查询(表名1:a 表名2:b) YX*Qd$chZ
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) OaL\w
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5、说明:显示文章、提交人和最后回复时间 7h)iu9j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b K+6e?5t
6、说明:外连接查询(表名1:a 表名2:b) qL94SW;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )TmHhNo
7、说明:在线视图查询(表名1:a ) Ldn8
select * from (SELECT a,b,c FROM a) T where t.a > 1; CXCpqcC
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 5MSB dO
select * from table1 where time between time1 and time2 ce6__f5?
select a,b,c, from table1 where a not between 数值1 and 数值2 FW.$5*f='
9、说明:in 的使用方法 EJ`T$JD
select * from table1 where a [not] in ('值1','值2','值4','值6') x=#VX\5k:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 D?Ux[O zb
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l
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11、说明:四表联查问题: Xj*vh
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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 ..... #A8@CA^d
12、说明:日程安排提前五分钟提醒 P/`I.p ;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^#0U ?9
13、说明:一条sql 语句搞定数据库分页 7L^%x3-|&
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 Xo*DvD
14、说明:前10条记录 sp*Vqd
select top 10 * form table1 where 范围 03j]d&P%d
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.) w eQYQrN
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) MJ=)v]a
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 WlYs~(=9
(select a from tableA ) except (select a from tableB) except (select a from tableC) P<fnLQ9
17、说明:随机取出10条数据 Q%-di=
select top 10 * from tablename order by newid() R-:fd!3oQ
18、说明:随机选择记录 ,E.' o=Z
select newid() ]
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19、说明:删除重复记录 M,5"b+mX[~
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \qUKP"dr
20、说明:列出数据库里所有的表名 Q#IG;
select name from sysobjects where type='U' `~X!Ll
21、说明:列出表里的所有的 F V,4pi
select name from syscolumns where id=object_id('TableName') ,y%3mR_~
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。 _Ob@`
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 Iz[@^IUx=
显示结果: jM:Y'l]
type vender pcs =LTmr1?
电脑 A 1 *kIc9}
电脑 A 1 +,2Jzl'-
光盘 B 2 $TI5vhQ
光盘 A 2 RQFI'@Ks
手机 B 3 +<prgP`v
手机 C 3 ;us%/kOR
23、说明:初始化表table1 eX_D/25 $
TRUNCATE TABLE table1 jV8q)=}*)
24、说明:选择从10到15的记录 s#uJ
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "l >Igm
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三、技巧 4H+Ked&Oq
1、1=1,1=2的使用,在SQL语句组合时用的较多 s{w[b\rA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !p1qJ [
如: uw},`4`
if @strWhere !='' M4WiT<|]R
begin m E^o-9/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4tx|=;@0
end )(7&X45,k
else !pJeA)W;
begin *9p |HX=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?<*-j4v
end 9 fMau
我们可以直接写成 2!Bd2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere X";@T.ZGut
2、收缩数据库 w}{5#
--重建索引 zm,@]!wI
DBCC REINDEX "k Te2iS
DBCC INDEXDEFRAG -n0C4 kZ2o
--收缩数据和日志 f7I{WfZ\P
DBCC SHRINKDB 76vy5R(.
DBCC SHRINKFILE ~y$ !48o
3、压缩数据库 Jxqh)l
dbcc shrinkdatabase(dbname) F]mgmYD%
4、转移数据库给新用户以已存在用户权限 $x6$*K(F
exec sp_change_users_login 'update_one','newname','oldname' %AN/>\#p
go &P,^.'
5、检查备份集 ?X&6M;Zi
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' zX#%{#9
6、修复数据库 `HuCT6O
ALTER DATABASE [dvbbs] SET SINGLE_USER w{dIFvQ"$
GO |7KeR-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK rDdzxrKg{
GO )NR Q2
ALTER DATABASE [dvbbs] SET MULTI_USER .`CZUKG
GO R<x'l=,D(
7、日志清除 dCu'>G\bP
SET NOCOUNT ON _uc\ D
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DECLARE @LogicalFileName sysname, ip~$X2
@MaxMinutes INT, KgW:@X7wvM
@NewSize INT "KJ%|pg_C
USE tablename -- 要操作的数据库名 Z@gnsPN^r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =:SN1#G3n
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Bb{!Yh].:A
@NewSize = 1 -- 你想设定的日志文件的大小(M) >*$;
-- Setup / initialize GjB]KA^
DECLARE @OriginalSize int *z'yk*
SELECT @OriginalSize = size }CxvT`/
FROM sysfiles OMk5{-8B
WHERE name = @LogicalFileName 0[<~?`:)
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 5b/ojr7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8_K60eXz
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +wW@'X
FROM sysfiles U}$DhA"r"
WHERE name = @LogicalFileName "S&%w8V
CREATE TABLE DummyTrans >]=j'+]
(DummyColumn char (8000) not null) na^sBq?\
DECLARE @Counter INT, MuBx#M/
@StartTime DATETIME, "g+z !4b#
@TruncLog VARCHAR(255) @u._"/K
SELECT @StartTime = GETDATE(), t\v+ogbk)
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >5G>D~b
DBCC SHRINKFILE (@LogicalFileName, @NewSize) C!C|\$)-
EXEC (@TruncLog) MCh#="L2
-- Wrap the log if necessary. HMY@F_qY`u
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Dr;iQkGP
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) MlW 8t[
AND (@OriginalSize * 8 /1024) > @NewSize u
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BEGIN -- Outer loop. 1b9hE9a{j
SELECT @Counter = 0 6bBdIqGb}
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'lZ.j&
BEGIN -- update V\K<$?oUb
INSERT DummyTrans VALUES ('Fill Log') T#Z%y!6
DELETE DummyTrans LEEC W_:
SELECT @Counter = @Counter + 1 XR0O;JN
END S-+M;@'Rl
EXEC (@TruncLog) q8ImrC.'^
END AnZclqtb
SELECT 'Final Size of ' + db_name() + ' LOG is ' + B}d.#G+_$x
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + bAr` E
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' D5?phyC[Z
FROM sysfiles [@fz1{*
WHERE name = @LogicalFileName Lhh;2r/?78
DROP TABLE DummyTrans (Vg}Hh?p
SET NOCOUNT OFF Q)af|GW$
8、说明:更改某个表 }1-I[q6
exec sp_changeobjectowner 'tablename','dbo' z<]bv7V
9、存储更改全部表 s=Q(C[%I
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 9SMiJad<
@OldOwner as NVARCHAR(128), r.0oxH']
@NewOwner as NVARCHAR(128) <5@PWrU?[[
AS nW?R"@Zm
DECLARE @Name as NVARCHAR(128) S'B6jJK2x
DECLARE @Owner as NVARCHAR(128) xv7"WFb
DECLARE @OwnerName as NVARCHAR(128) ;3C:%!CdA]
DECLARE curObject CURSOR FOR ;7Oi! BC
select 'Name' = name, X5g[ :QKP7
'Owner' = user_name(uid) p4VSma_(
from sysobjects PNSMcakD
where user_name(uid)=@OldOwner VhEM k\
order by name ,)~E>[=+
OPEN curObject [&Hkn5yq
FETCH NEXT FROM curObject INTO @Name, @Owner f c6g
WHILE(@@FETCH_STATUS=0) >u J/TQU
BEGIN x O7IzqY
if @Owner=@OldOwner rsa&Oo
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begin )R{UXk3q}
set @OwnerName = @OldOwner + '.' + rtrim(@Name) jw6Tj;c
exec sp_changeobjectowner @OwnerName, @NewOwner O7aLlZdg~
end u1K\@jlw
-- select @name,@NewOwner,@OldOwner NE|[o0On
FETCH NEXT FROM curObject INTO @Name, @Owner 0=v{RQ;W4
END *Dr5O 9Y
close curObject ;LJ3c7$@lf
deallocate curObject M,:Bl}
GO d`Q7"}uZ
10、SQL SERVER中直接循环写入数据 wb"RB
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declare @i int > 7`&0?
set @i=1 f"&Xr!b.h
while @i<30 #k5#j4!b
begin }fhHXGK.
insert into test (userid) values(@i) 0'$p$K
set @i=@i+1 ?a/n<V '
end UEz i*"-v2
小记存储过程中经常用到的本周,本月,本年函数 !d9AG|
Dateadd(wk,datediff(wk,0,getdate()),-1) A~lIa$U$b
Dateadd(wk,datediff(wk,0,getdate()),6) >{Rb 3Z]
Dateadd(mm,datediff(mm,0,getdate()),0) @{Py %
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 3]E(mRX
Dateadd(yy,datediff(yy,0,getdate()),0) J7-^F)lu-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) o4=Yu7L
上面的SQL代码只是一个时间段 Gk~l,wV>
Dateadd(wk,datediff(wk,0,getdate()),-1) 1K|@h&@
Dateadd(wk,datediff(wk,0,getdate()),6) kReG:
就是表示本周时间段. "PpjoM
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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: nq`q[KV:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) bdc\
而在存储过程中 iRmQ5ezk
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [~Hg}-c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0o&}mKe