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。 E&9BeU
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一、基础 {%gMA?b|"
1、说明:创建数据库 zb.dVK`7N-
CREATE DATABASE database-name d#NG]V/
2、说明:删除数据库 G*^4+^Vz?
drop database dbname GUSEbIz):
3、说明:备份sql server )H8Rfn?
--- 创建 备份数据的 device Dn~c
USE master yH/m@#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' _TEjB:9eY
--- 开始 备份 MfQ 9d9
BACKUP DATABASE pubs TO testBack j`7q7}
4、说明:创建新表 Bq@_/*'*Y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) bi~1d"j
根据已有的表创建新表: }hRw{#*8
A:create table tab_new like tab_old (使用旧表创建新表) [_PZdIN
B:create table tab_new as select col1,col2... from tab_old definition only 05hjC
5、说明:删除新表 LD/NMb
drop table tabname lub_2Cb|j
6、说明:增加一个列 4h~CDy%_
Alter table tabname add column col type ip8%9fG\>
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。 fRh}n ^X
7、说明:添加主键: Alter table tabname add primary key(col) ZD ~ra7
说明:删除主键: Alter table tabname drop primary key(col) {9B"'65o
8、说明:创建索引:create [unique] index idxname on tabname(col....) =Z}$X:
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删除索引:drop index idxname j]P'xrWl]8
注:索引是不可更改的,想更改必须删除重新建。 z[|2od
9、说明:创建视图:create view viewname as select statement iC2``[m"
删除视图:drop view viewname -?z#
10、说明:几个简单的基本的sql语句 }JI@f14
选择:select * from table1 where 范围 [0MNq]gxf
插入:insert into table1(field1,field2) values(value1,value2) ?sD4S
删除:delete from table1 where 范围 JCO+_d#x
更新:update table1 set field1=value1 where 范围 Gu@n1/m@o
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! sBm)D=Kll
排序:select * from table1 order by field1,field2 [desc] LT[g
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总数:select count as totalcount from table1 c]}F$[>oN'
求和:select sum(field1) as sumvalue from table1 mUA!GzJ~u-
平均:select avg(field1) as avgvalue from table1 SR_<3WW
最大:select max(field1) as maxvalue from table1 v9*31Jx
最小:select min(field1) as minvalue from table1 ]"ou?ot }
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11、说明:几个高级查询运算词 *\gYs{,
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A: UNION 运算符 0#Ae<
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。 717S3knlv
B: EXCEPT 运算符 3LRBH+Tt
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。 ^m
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C: INTERSECT 运算符 6U9FvPJ
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。 1Be/(pSc
注:使用运算词的几个查询结果行必须是一致的。 m941 Y
12、说明:使用外连接 WF] |-)vw
A、left outer join: ghGpi U$
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。 g~p43sVV
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 BD,J4xH;
B:right outer join: g>E.Snj}
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。 tJ$gH;
C:full outer join: 2Y>#FEW/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 4ibOVBG:*,
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二、提升 []:&WA9N
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) (h"-#q8$
法一:select * into b from a where 1<>1 LIE5of
法二:select top 0 * into b from a d0V*[{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) w~4T.l#1
insert into b(a, b, c) select d,e,f from b; \&/V p`
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)
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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 l#IN)">1
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. YJGP8
4、说明:子查询(表名1:a 表名2:b) otA'+4\
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) Yz)+UF,
5、说明:显示文章、提交人和最后回复时间 #$X _,+<HZ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b uA4xxY
6、说明:外连接查询(表名1:a 表名2:b) muAgsH$/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =O%'qUj`q
7、说明:在线视图查询(表名1:a ) !LM9
select * from (SELECT a,b,c FROM a) T where t.a > 1; FQBE1h@k0u
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 ',Y`\X
select * from table1 where time between time1 and time2 nc3usq
select a,b,c, from table1 where a not between 数值1 and 数值2 8 qlQC.VA[
9、说明:in 的使用方法 I= 2jQ>$Q
select * from table1 where a [not] in ('值1','值2','值4','值6') J4%"38l
10、说明:两张关联表,删除主表中已经在副表中没有的信息 *b7evU *1
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) % oJH 6F
11、说明:四表联查问题: ]TVc 'G;
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 ..... _1G;!eO
12、说明:日程安排提前五分钟提醒 G5hf m-
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 f cnv[B..{
13、说明:一条sql 语句搞定数据库分页 jr(|-!RVMN
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 KwNOB _
14、说明:前10条记录 0SR[)ma
select top 10 * form table1 where 范围 & LhQr-g
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.) %mAwK<MY`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) bgeJVI
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 MFn\[J`Ra
(select a from tableA ) except (select a from tableB) except (select a from tableC) "[ieOFI
17、说明:随机取出10条数据 M1=eS@
select top 10 * from tablename order by newid() 3 S .2
18、说明:随机选择记录 vddl9"V)
select newid() C<#_1@^:8e
19、说明:删除重复记录 h t3P@;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =6a=`3r!I
20、说明:列出数据库里所有的表名 G/ H>M%M
select name from sysobjects where type='U' b,x$wP+
21、说明:列出表里的所有的 b#-=Dbe
select name from syscolumns where id=object_id('TableName') ?)g [Xc;K
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 <m/XGFc
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type iD.p KG
显示结果: cx[[K.
type vender pcs i0u`J
电脑 A 1 RdB,;Um9f
电脑 A 1 fI,2l
光盘 B 2 tn;Uaw
光盘 A 2 8=)9ZjfD
手机 B 3 _\<TjGtG
手机 C 3 =om<* \vsO
23、说明:初始化表table1 +&r=XJ5:`p
TRUNCATE TABLE table1 L|8&9F\
24、说明:选择从10到15的记录 %%9T-+T
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p7W9?b9
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三、技巧 Yyw9IYB;
1、1=1,1=2的使用,在SQL语句组合时用的较多 @"B{k%+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~x[(1
如: GL _hRu
if @strWhere !='' J|
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begin `YY07(%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere FE1'MUT_
end Y.q$"lm7k
else cqaq~
begin OepQ Z|2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Gzp*Vr
end v%kl*K`*
我们可以直接写成 }zIWagC6
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )Y`ybADd3
2、收缩数据库 Bjh8uW
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--重建索引 1)5/a5
DBCC REINDEX ;Fd1:"1pP
DBCC INDEXDEFRAG /8 yv8
--收缩数据和日志 *TrpW?]Y&
DBCC SHRINKDB J3XG?'
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DBCC SHRINKFILE ve\@u@K^
3、压缩数据库 (Vn3g ra
dbcc shrinkdatabase(dbname) |tC= j.
4、转移数据库给新用户以已存在用户权限 QRx9;!~b}
exec sp_change_users_login 'update_one','newname','oldname' 3vkzN
go "MD6 <H
5、检查备份集 A@;{#.O
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e:K'e2
6、修复数据库 0$i\/W+
ALTER DATABASE [dvbbs] SET SINGLE_USER xf?"Q#
GO ,&g-DCag
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `4e| I.`^r
GO Y5y7ONcn
ALTER DATABASE [dvbbs] SET MULTI_USER ;X:Bh8tEV
GO 8K@e8p( y
7、日志清除 Md0`/F:+2
SET NOCOUNT ON 3[@:I^q
DECLARE @LogicalFileName sysname, 2Sk hBb=d
@MaxMinutes INT, y4VO\N!
@NewSize INT VtMnLFMw
USE tablename -- 要操作的数据库名 $
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `<#O8,7`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N!Xn)J
@NewSize = 1 -- 你想设定的日志文件的大小(M) "([lkn
-- Setup / initialize 3m~,6mQ
DECLARE @OriginalSize int Q[FDk63;w
SELECT @OriginalSize = size I+`>e*:@W
FROM sysfiles r*ziO#[
WHERE name = @LogicalFileName [ {HTGz@(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;Aheeq746
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \mZB*k)+
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' lk`|u$KPz
FROM sysfiles )` S5>[6
WHERE name = @LogicalFileName 7q{yLcC"
CREATE TABLE DummyTrans dA<SVk*0Q
(DummyColumn char (8000) not null) .J=QWfqt
DECLARE @Counter INT, <tm=
@StartTime DATETIME, +jS<n13T
@TruncLog VARCHAR(255) '+GY6Ecg
SELECT @StartTime = GETDATE(), O_ vH w^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ItVVI"-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p<&>1}j=
EXEC (@TruncLog) Y/LS(b*
-- Wrap the log if necessary. / 8u}VYE
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired :H#D4O8UiH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >[~`rOU*|Y
AND (@OriginalSize * 8 /1024) > @NewSize ztAC3,r]
BEGIN -- Outer loop. BqpJvRJd
SELECT @Counter = 0 L=.@hs
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I}|E_U1Qj
BEGIN -- update 9ph>4u(R
INSERT DummyTrans VALUES ('Fill Log') (4IP&^j:\
DELETE DummyTrans ;kZJnN"y
SELECT @Counter = @Counter + 1 zn0%%x+!g
END oTr,zRL
EXEC (@TruncLog) e.Q'l/g
END ;iQw2XhT
SELECT 'Final Size of ' + db_name() + ' LOG is ' + y-S23B(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + \?|^w.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0g
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FROM sysfiles @i#=1)Ze
WHERE name = @LogicalFileName |+Z-'k~Q
DROP TABLE DummyTrans IsVR4t]
SET NOCOUNT OFF YS<KyTb"
8、说明:更改某个表 Q'Uv5p"X
exec sp_changeobjectowner 'tablename','dbo' 7UqDPEXU]`
9、存储更改全部表 4QYStDFe
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch vbtjPse
@OldOwner as NVARCHAR(128), 7mn&w$MS4:
@NewOwner as NVARCHAR(128) sQ&<cBs2
AS -
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DECLARE @Name as NVARCHAR(128) `Gx
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DECLARE @Owner as NVARCHAR(128) |oQhtk8.
DECLARE @OwnerName as NVARCHAR(128) m 0Uu2Z4
DECLARE curObject CURSOR FOR p^Z|$aZZ
select 'Name' = name, 9H53H"5q
'Owner' = user_name(uid) VMS3Q)Ul
from sysobjects A;e"_$yt8
where user_name(uid)=@OldOwner `=kiqF2P}
order by name d7uS[tKqg
OPEN curObject #Fgybokm
FETCH NEXT FROM curObject INTO @Name, @Owner 2Ky|+s[`[
WHILE(@@FETCH_STATUS=0) {bC(>k|CQ
BEGIN P,7R/-u 5D
if @Owner=@OldOwner jF(R;?,
begin ]vw%J ^7:a
set @OwnerName = @OldOwner + '.' + rtrim(@Name) p _2Y c]8
exec sp_changeobjectowner @OwnerName, @NewOwner 6KE64: \;
end 7f*b5$+r
-- select @name,@NewOwner,@OldOwner )%
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FETCH NEXT FROM curObject INTO @Name, @Owner :OqEkh"$#
END 1_8@yO
close curObject <p?oFD_e4
deallocate curObject 8|u8J0^
GO jN(c`Gb
10、SQL SERVER中直接循环写入数据 T t_QAIl
declare @i int 'b6qEU#
set @i=1 I9nm$,i]7
while @i<30 \K lY8\c[
begin +x?8\
insert into test (userid) values(@i) };'~@%U]/
set @i=@i+1 .R#<Q
end kt7Em b}
小记存储过程中经常用到的本周,本月,本年函数 2+K-I
Dateadd(wk,datediff(wk,0,getdate()),-1) Cd_H<8__
Dateadd(wk,datediff(wk,0,getdate()),6) %fXgV\xY
Dateadd(mm,datediff(mm,0,getdate()),0) {@'#|]4y.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) R <&U]%FD
Dateadd(yy,datediff(yy,0,getdate()),0) 67||wh.BU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) umpa!q};
上面的SQL代码只是一个时间段 n"vO?8Sx
Dateadd(wk,datediff(wk,0,getdate()),-1) YllW2g:
Dateadd(wk,datediff(wk,0,getdate()),6) !G<gp4Js+N
就是表示本周时间段. @lqI,Ce5
下面的SQL的条件部分,就是查询时间段在本周范围内的: `'9t^6mk
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 5!57<n
而在存储过程中 T?1e&H%USV
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) er@.<Dc
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) c'Q.2^w^