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。 *=$[}!YG
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一、基础 CF3E]dt
1、说明:创建数据库 ~@[(N]=q
CREATE DATABASE database-name '?{0z!!
2、说明:删除数据库 /,1SE(
drop database dbname hi ;WFyJTu
3、说明:备份sql server <CNE>@-f
--- 创建 备份数据的 device 4NpHX+=P
USE master T>\nWancQM
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i(M(OR/4
--- 开始 备份 H_%d3 RI
BACKUP DATABASE pubs TO testBack [<D+pqh
4、说明:创建新表 $:f.Krj
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) tk`: CT
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根据已有的表创建新表: 84[|qB,ML
A:create table tab_new like tab_old (使用旧表创建新表) }iPo8Ra
B:create table tab_new as select col1,col2... from tab_old definition only PoYr:=S?
5、说明:删除新表 QO5OnYh
drop table tabname ; @7
6、说明:增加一个列 eZ!yPdgy|
Alter table tabname add column col type f![xn2T
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 V.K70)]
7、说明:添加主键: Alter table tabname add primary key(col) ZhGh{D[,
说明:删除主键: Alter table tabname drop primary key(col) Nl~Z,hT$*
8、说明:创建索引:create [unique] index idxname on tabname(col....) U/.w;DI
删除索引:drop index idxname !: m`9o8
注:索引是不可更改的,想更改必须删除重新建。 :0M'=~[
9、说明:创建视图:create view viewname as select statement " 2ZI oa!^
删除视图:drop view viewname u{g]gA8s
10、说明:几个简单的基本的sql语句 ?JuX~{{.L
选择:select * from table1 where 范围 ~8jThi
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插入:insert into table1(field1,field2) values(value1,value2) KH>Sc3p
删除:delete from table1 where 范围 `xISkW4 %
更新:update table1 set field1=value1 where 范围 =:4'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *4|9&PNLE
排序:select * from table1 order by field1,field2 [desc] hf_R\C(c
总数:select count as totalcount from table1 | f"-|6
求和:select sum(field1) as sumvalue from table1 q$MHCq;
平均:select avg(field1) as avgvalue from table1 |9+bSH9
最大:select max(field1) as maxvalue from table1 _n<
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最小:select min(field1) as minvalue from table1 96vj)ql
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11、说明:几个高级查询运算词 =RQ )$ %
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A: UNION 运算符 Q8 -3RgAw
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。 ZvUp#8x(3
B: EXCEPT 运算符 P-[fHCg~
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。 (YAI,Xnw
C: INTERSECT 运算符 jZa25Z00
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。 OF-E6b c
注:使用运算词的几个查询结果行必须是一致的。 !c\7
12、说明:使用外连接 X"kXNKV/n
A、left outer join: >ysriPnQ
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。 .KFA218h*x
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 l!\1,J:}Z
B:right outer join: IKvd!,0xf
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。 uPFRh~ (b
C:full outer join: G5!|y#T
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。 B`LD7]ew
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二、提升 ktN%!Mh\
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) kclp}
法一:select * into b from a where 1<>1 XlRw Z/Wc
法二:select top 0 * into b from a W7%p^;ZQ$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) zs4>/9O
insert into b(a, b, c) select d,e,f from b; P`}$-#D F
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Pg7>ce
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 xy2\'kS`G
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {V.Wk
4、说明:子查询(表名1:a 表名2:b) Z/xV\Ggx
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) <H<!ht%q3
5、说明:显示文章、提交人和最后回复时间 \.5F](:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b :}^Rs9 '
6、说明:外连接查询(表名1:a 表名2:b) ]t*33
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :b"=KQ
7、说明:在线视图查询(表名1:a ) M#ZT2~+CT
select * from (SELECT a,b,c FROM a) T where t.a > 1; M#`{>R|
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 <sa #|Y$
select * from table1 where time between time1 and time2 yU *u
select a,b,c, from table1 where a not between 数值1 and 数值2 %=y;L:S\p
9、说明:in 的使用方法 YFG-U-t3
select * from table1 where a [not] in ('值1','值2','值4','值6') T]^?l
10、说明:两张关联表,删除主表中已经在副表中没有的信息 N"S3N)wgd
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) J(4g4?
11、说明:四表联查问题: t5%TS:u
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 ..... 9`&?hi49nK
12、说明:日程安排提前五分钟提醒 S3ErH,XB.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `a-Bji?
13、说明:一条sql 语句搞定数据库分页 %z30=?VL
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 P%iP:16
14、说明:前10条记录 z3clUtC+
select top 10 * form table1 where 范围 64SW
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.) \e_IFISC
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {JXf*IJ
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 kl=xu3j
(select a from tableA ) except (select a from tableB) except (select a from tableC) b,9@P&=:2
17、说明:随机取出10条数据 2v4W6R
select top 10 * from tablename order by newid() N5yJ'i~,M
18、说明:随机选择记录 >A<Df
select newid() *E.LP1xP
19、说明:删除重复记录 cbfDB^_
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ;;M"hI3@
20、说明:列出数据库里所有的表名 ]7*kWc2
select name from sysobjects where type='U' ;3mL^
21、说明:列出表里的所有的 Is
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select name from syscolumns where id=object_id('TableName') iZC>)&ax
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。 KVg[#~3
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 ?gU }[]
显示结果: _wmI(+_
type vender pcs HV8I nodi
电脑 A 1 }*h47t}
电脑 A 1 V- /YNRV
光盘 B 2 kY=rz&?U
光盘 A 2 }4Zkf<#7$
手机 B 3 f`,-b
手机 C 3 5lGQ#r
23、说明:初始化表table1 axtb<5&
TRUNCATE TABLE table1 *-6?
24、说明:选择从10到15的记录 iM"asEU
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc v_.HGGS
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三、技巧 vf[&7n
1、1=1,1=2的使用,在SQL语句组合时用的较多 \Y+")
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dIvy!d2l
如: RJ@\W=aZ
if @strWhere !='' JwB"\&'1ZS
begin cu)U7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere @cPflb
end a#$N% =j
else qIz}$%!A
begin mf$Sa58
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' g
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end
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我们可以直接写成 i@XB&;*c\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere P<vo;96JT
2、收缩数据库 ##v`(#fu
--重建索引 7LfcF
DBCC REINDEX iKhH ^V%j
DBCC INDEXDEFRAG *Z; r
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--收缩数据和日志 V3Yd&HVWNQ
DBCC SHRINKDB IytDvz*|
DBCC SHRINKFILE g>yry}>04%
3、压缩数据库 /9Z!p
dbcc shrinkdatabase(dbname) V:OiW"/
4、转移数据库给新用户以已存在用户权限 Jr]gEBX
exec sp_change_users_login 'update_one','newname','oldname' *!w25t
go 68p R:
5、检查备份集 F_v-}bbcFQ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T{tn.sT
6、修复数据库 *,&S' ,S-
ALTER DATABASE [dvbbs] SET SINGLE_USER 9n"V\e_R
GO Kr]z]4.d@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK kutJd{68
GO /kRAt^4!
ALTER DATABASE [dvbbs] SET MULTI_USER +j.qZ8
GO Q ?^4 \_
7、日志清除 t3a#%'Dv
SET NOCOUNT ON r%|A$=[Q
DECLARE @LogicalFileName sysname, t!:)L+$3
@MaxMinutes INT, o0l74
@NewSize INT <aXoB*Y
USE tablename -- 要操作的数据库名 C `6S}f,
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Mb.4J2F ?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. H{%H^t>
@NewSize = 1 -- 你想设定的日志文件的大小(M) T
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-- Setup / initialize *{|$FQnR>(
DECLARE @OriginalSize int oqYt/4^Q
SELECT @OriginalSize = size `7\H41%\pp
FROM sysfiles A?r^V2+j
WHERE name = @LogicalFileName X$^JAZ09
SELECT 'Original Size of ' + db_name() + ' LOG is ' + VX!hv`E
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :BD>yOlG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' /tZ0
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FROM sysfiles -?z\5z
WHERE name = @LogicalFileName @$c!/
CREATE TABLE DummyTrans @Z q[e
(DummyColumn char (8000) not null) N2Ssf$
DECLARE @Counter INT, >Nh`rkR2[
@StartTime DATETIME, = ^s$
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@TruncLog VARCHAR(255) c0ZaFJ
SELECT @StartTime = GETDATE(), N&m_e)E5c
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5gshKmt_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) V&iS~V0.
EXEC (@TruncLog) wDKELQ(yH
-- Wrap the log if necessary. >vAN(3Idu
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0X>T+A[E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~b6GrY"vB
AND (@OriginalSize * 8 /1024) > @NewSize ?
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BEGIN -- Outer loop. TF2KZL#A|
SELECT @Counter = 0 ve fU'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) n"Z |e tZ4
BEGIN -- update Y{+3}drJE
INSERT DummyTrans VALUES ('Fill Log') *)D1!R<\,R
DELETE DummyTrans :j,}{)5=
SELECT @Counter = @Counter + 1 $DE&J4K
END Y[um|M315
EXEC (@TruncLog) fEwifSp.
END PIxjM>
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3AeH7g4<
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [0!{_E)<
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' :c:V%0Yji
FROM sysfiles bLlH//ZRH
WHERE name = @LogicalFileName (NaK3_
DROP TABLE DummyTrans "V}qf3qU
SET NOCOUNT OFF J@Yj\9U
8、说明:更改某个表 4K7{f+T
exec sp_changeobjectowner 'tablename','dbo' cz(G]{N
9、存储更改全部表 niz 'b]] +
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch wE6A
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@OldOwner as NVARCHAR(128), 328L)BmW
@NewOwner as NVARCHAR(128) V|: qow:F
AS Z&Pu8zG
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DECLARE @Name as NVARCHAR(128) hKN6 y%
DECLARE @Owner as NVARCHAR(128) z_n\5.
DECLARE @OwnerName as NVARCHAR(128) D/:3RZF
DECLARE curObject CURSOR FOR no&-YktP}
select 'Name' = name, YtYy zX5u7
'Owner' = user_name(uid) P=gJAE5
from sysobjects _ZyT3P&
where user_name(uid)=@OldOwner u"Y]P*[k
order by name 8,*3zVk-
OPEN curObject Q0>q:aj\
FETCH NEXT FROM curObject INTO @Name, @Owner 'RLOV
WHILE(@@FETCH_STATUS=0) CXAVGO'xw
BEGIN |}Ph"g2D,
if @Owner=@OldOwner &,MFB
begin m\-PU z&C
set @OwnerName = @OldOwner + '.' + rtrim(@Name) s)w9%
exec sp_changeobjectowner @OwnerName, @NewOwner moG~S]
end !\x?R6K
-- select @name,@NewOwner,@OldOwner "~\*If
FETCH NEXT FROM curObject INTO @Name, @Owner N RSU+D-z
END P
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close curObject p6[ (81
deallocate curObject -;Uj|^
GO 1`l;xw1W
10、SQL SERVER中直接循环写入数据 D#0O[F@l##
declare @i int h<NRE0-
set @i=1 <\aU"_D
while @i<30 ;?~
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begin '[0YIn
insert into test (userid) values(@i) Pa&4)OD
set @i=@i+1 u)~s4tP4
end 1<,/
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小记存储过程中经常用到的本周,本月,本年函数 lT,+bU
Dateadd(wk,datediff(wk,0,getdate()),-1) >r}Vf9 5[N
Dateadd(wk,datediff(wk,0,getdate()),6) ]sL45k2W
Dateadd(mm,datediff(mm,0,getdate()),0) nk/vGa4
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) iN)af5)[^
Dateadd(yy,datediff(yy,0,getdate()),0) {Hk/1KG>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Le@?
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上面的SQL代码只是一个时间段 sfI N)jh
Dateadd(wk,datediff(wk,0,getdate()),-1) BX3lPv
Dateadd(wk,datediff(wk,0,getdate()),6) i0ybJOa4
就是表示本周时间段. LNiS`o\
下面的SQL的条件部分,就是查询时间段在本周范围内的: a.,_4;'UE1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +)gB9DoK
而在存储过程中 [ {cC
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HJ@5B"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m
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