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。 Zz!XH8sH
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一、基础 fFMGpibkM
1、说明:创建数据库 p^3]Q
CREATE DATABASE database-name ='`z
2、说明:删除数据库 Y4_/G4C
drop database dbname F@1~aeX-
3、说明:备份sql server .__XOd}K
--- 创建 备份数据的 device @i'RIL}
USE master Q})x4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Ynl^Z
--- 开始 备份 A5S9F8Q/]
BACKUP DATABASE pubs TO testBack 1p[C5j3
4、说明:创建新表 64%P}On
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ` .|JTm[
根据已有的表创建新表: [a:yKJ[
A:create table tab_new like tab_old (使用旧表创建新表) ,|D_? D)U
B:create table tab_new as select col1,col2... from tab_old definition only 5Ev9u),D+v
5、说明:删除新表 ] JVs/
drop table tabname 4/;hA
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6、说明:增加一个列 k@L},Td
Alter table tabname add column col type /BjM&v(5/
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。 12`q9Io"
7、说明:添加主键: Alter table tabname add primary key(col) "1FPe63\*O
说明:删除主键: Alter table tabname drop primary key(col) DzydS=`w
8、说明:创建索引:create [unique] index idxname on tabname(col....) V7[6jWgH
删除索引:drop index idxname E
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注:索引是不可更改的,想更改必须删除重新建。 X;lL$
9、说明:创建视图:create view viewname as select statement 9UsA>m.
删除视图:drop view viewname )_k"_VVcC
10、说明:几个简单的基本的sql语句 IppzQ0'=y1
选择:select * from table1 where 范围 Ls< ";QJc
插入:insert into table1(field1,field2) values(value1,value2) @<=x fs
删除:delete from table1 where 范围 Uy2NZ%rnt
更新:update table1 set field1=value1 where 范围 "(zvI>A
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #tg,%*.s
排序:select * from table1 order by field1,field2 [desc] DDxbIkt
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 YT'G#U1x~
平均:select avg(field1) as avgvalue from table1 4[m})X2(
最大:select max(field1) as maxvalue from table1 /j/,@,lw7z
最小:select min(field1) as minvalue from table1 F0:|uC4
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11、说明:几个高级查询运算词 Ir&rTGFN
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A: UNION 运算符 hsG~xRA\
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。 O#LG$Y
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B: EXCEPT 运算符 =r"-Pm{
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 &|yQwNA*a"
C: INTERSECT 运算符 ~QgyhJM_h=
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 TRP#b 7nC
注:使用运算词的几个查询结果行必须是一致的。 q.0Evr:
12、说明:使用外连接 +`tl<rg;
A、left outer join: i[_(0P+Da
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 yMaU`z
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5.m&93P
B:right outer join: p)6!GdT
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 R=
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C:full outer join: 1P4cBw%
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 JjA3G`m=
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二、提升 jz,Mm,Gi
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [.J&@96,b
法一:select * into b from a where 1<>1 wpgO09
法二:select top 0 * into b from a MDV<[${
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ?YE'J~0A6
insert into b(a, b, c) select d,e,f from b; -#<6
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) W>f q 9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 .5L|(B=H
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. s?Lx\?T
4、说明:子查询(表名1:a 表名2:b) >QyJRMY
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) tfB}U.
5、说明:显示文章、提交人和最后回复时间 H<_BnT#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b dbn9t7'{
6、说明:外连接查询(表名1:a 表名2:b) L\0;)eJ#M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c N>ncv
7、说明:在线视图查询(表名1:a ) w>#{Nl7gz
select * from (SELECT a,b,c FROM a) T where t.a > 1; ot\ FZ
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 ;f;A"
select * from table1 where time between time1 and time2 F1_s%&
select a,b,c, from table1 where a not between 数值1 and 数值2 m=Mb'<
9、说明:in 的使用方法 (V&5EO8)
select * from table1 where a [not] in ('值1','值2','值4','值6') o>|&k]W/
10、说明:两张关联表,删除主表中已经在副表中没有的信息 AWaptw_p*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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11、说明:四表联查问题: A]0A,A0
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 ..... &10l80vj
12、说明:日程安排提前五分钟提醒 hcn$uyP
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ?^Gi;d5
13、说明:一条sql 语句搞定数据库分页 ,+w9_Gy2H
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 w8=&rzr8
14、说明:前10条记录 Vn&{yCm3
select top 10 * form table1 where 范围 r]q;>\T'
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) f^JiaU4 [
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5(wmy-x\
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 r ^=rs!f@
(select a from tableA ) except (select a from tableB) except (select a from tableC) EPEWyGw
17、说明:随机取出10条数据 8y:/!rRN
select top 10 * from tablename order by newid() { 6
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18、说明:随机选择记录 -VZn`6%s
select newid() DWv(|gO
19、说明:删除重复记录 Wd`*<+t]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) cNbH:r"Ay
20、说明:列出数据库里所有的表名 oW}nr<G{<
select name from sysobjects where type='U' } 6 ,m2u
21、说明:列出表里的所有的 )Ehi8
select name from syscolumns where id=object_id('TableName') LN z
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ./]xn
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type .7K)'
显示结果: &9Y ^/W
type vender pcs <`$svM
电脑 A 1 mpr_AL!ZO~
电脑 A 1 dU}Cb?]7s
光盘 B 2 m+UWvUB)
光盘 A 2 Sp7VH+
手机 B 3 R$XHjb)
手机 C 3 WC Tmf8f
23、说明:初始化表table1 e{Q;,jsh
TRUNCATE TABLE table1 ai7R@~O:_k
24、说明:选择从10到15的记录 qt(+X
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Hs:0j$
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三、技巧 (k^%j
1、1=1,1=2的使用,在SQL语句组合时用的较多 &Fiesi!tET
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W
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如: 4,,DA2^!
if @strWhere !='' %p48=|+
begin H(hE;|q/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere bO i-QD
end 6i+<0b}!/
else ~dO+kD
begin gt(^9t;
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' vp32}zeD
end (ZPl~ZO
我们可以直接写成 !>:SPt l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere _<E.?K$gbU
2、收缩数据库 T_)g/,5>
--重建索引 {|d28!8w
DBCC REINDEX M(^_/1Z
DBCC INDEXDEFRAG kYhV1I
--收缩数据和日志 )[S#:PP
DBCC SHRINKDB F?z:[1(:
DBCC SHRINKFILE (*M*muk
3、压缩数据库 .5" s[(S
dbcc shrinkdatabase(dbname) .FN;3HU
4、转移数据库给新用户以已存在用户权限 TU6(Q,Yi|
exec sp_change_users_login 'update_one','newname','oldname' mtg=v@~
go $@D*/@
5、检查备份集 L6?~<#-m\M
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 7|HIl=
6、修复数据库 vbD""
ALTER DATABASE [dvbbs] SET SINGLE_USER "S]G+/I|iw
GO kwXUjnp
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK {/FdrS
GO D6dliU?k
ALTER DATABASE [dvbbs] SET MULTI_USER Kv9$c(~#
GO 3PjX;U|
7、日志清除 S:K$fFcJ
SET NOCOUNT ON BTzBT%mP
DECLARE @LogicalFileName sysname, 1{ H=The
@MaxMinutes INT, X"jL
@NewSize INT s{Og3qUy
USE tablename -- 要操作的数据库名 /F$E)qN7n
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 P BVF'~f@j
@MaxMinutes = 10, -- Limit on time allowed to wrap log. vM@8&,;
@NewSize = 1 -- 你想设定的日志文件的大小(M) vX7U|zy
-- Setup / initialize fN1b+d~*6
DECLARE @OriginalSize int Vx}e,(i
SELECT @OriginalSize = size ddS3;Rk2
FROM sysfiles soRYM
WHERE name = @LogicalFileName n$lVmQ6
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?KB]
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + VbDk44X.W
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~?4BP%g-y
FROM sysfiles >~0~h:M+
WHERE name = @LogicalFileName 'yosDT2{#
CREATE TABLE DummyTrans m-6&-G#
(DummyColumn char (8000) not null) EKD#s,(V*X
DECLARE @Counter INT, l^XOW- ;u
@StartTime DATETIME, r#A*{4wz
@TruncLog VARCHAR(255) (wFoI}s
SELECT @StartTime = GETDATE(), ^AShy`o^X
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' oiIl\#C
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [dR#!"6t
EXEC (@TruncLog) ny%$BQM=
-- Wrap the log if necessary. (j~T7og
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;"2VU"
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) VP~(;H5%
AND (@OriginalSize * 8 /1024) > @NewSize !7f,g vk
BEGIN -- Outer loop. mrq,kwM
SELECT @Counter = 0 33SCHQ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cV"Ov@_.k
BEGIN -- update 3GNcnb
INSERT DummyTrans VALUES ('Fill Log') z9:yt5ar
DELETE DummyTrans jXVvVv
SELECT @Counter = @Counter + 1 L|Xg4Z
END hH9~.4+*`g
EXEC (@TruncLog) JljCI@
END 2">de/jS
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8f<y~L_(`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1 +s;a]-C
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !MrQ-B (
FROM sysfiles bEB2q\|Je
WHERE name = @LogicalFileName ie11syhV"
DROP TABLE DummyTrans c5| sda{
SET NOCOUNT OFF |g>Q3E
8、说明:更改某个表 )+"5($~
exec sp_changeobjectowner 'tablename','dbo' n=PfV3B
9、存储更改全部表 u(fZ^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch lu6iU
@OldOwner as NVARCHAR(128), C(9"59>{]y
@NewOwner as NVARCHAR(128) LXWI'nxV
AS qcouZO
DECLARE @Name as NVARCHAR(128) %Oo
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DECLARE @Owner as NVARCHAR(128) D)bL;h
DECLARE @OwnerName as NVARCHAR(128) xFekSH7[F
DECLARE curObject CURSOR FOR 6O/c%1VHA3
select 'Name' = name, )Fp$
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'Owner' = user_name(uid) S8B?uU
from sysobjects ?E_;[(Mcr
where user_name(uid)=@OldOwner nbB*d@"
order by name "G-h8IN^O
OPEN curObject kxN
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FETCH NEXT FROM curObject INTO @Name, @Owner 7AS_Aw1L
WHILE(@@FETCH_STATUS=0) 98)C
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BEGIN MRw4?HqB
if @Owner=@OldOwner ?:M4GY"gV
begin :h |]j[2p
set @OwnerName = @OldOwner + '.' + rtrim(@Name) |V4<eF-0S
exec sp_changeobjectowner @OwnerName, @NewOwner $.t>* Bq
end p!~1~q6
-- select @name,@NewOwner,@OldOwner D)pTE?@W'
FETCH NEXT FROM curObject INTO @Name, @Owner ).IyjHY
END vBJxhK-
close curObject Mo<q(_ZeRP
deallocate curObject c_CVZR?
GO g~b$WV%
10、SQL SERVER中直接循环写入数据 @ZjO#%Ep/
declare @i int O@
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set @i=1 $+f=l~/s
while @i<30 "OA{[)fw"
begin !zm;C@}ln
insert into test (userid) values(@i) 4;W{#jk
set @i=@i+1 M|j=J{r
end k0O5c[j
小记存储过程中经常用到的本周,本月,本年函数 %LzARTX
Dateadd(wk,datediff(wk,0,getdate()),-1) w~'}uh
Dateadd(wk,datediff(wk,0,getdate()),6) }3 _b%{
Dateadd(mm,datediff(mm,0,getdate()),0) -ycdg'v
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <YtjE!2
Dateadd(yy,datediff(yy,0,getdate()),0) %k32:qe
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4Ngp -
上面的SQL代码只是一个时间段 j}B86oX
Dateadd(wk,datediff(wk,0,getdate()),-1) yci} #,nb
Dateadd(wk,datediff(wk,0,getdate()),6) VH~YwO!x
就是表示本周时间段. hd i0YL
下面的SQL的条件部分,就是查询时间段在本周范围内的: lZ7
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) x{8h3.ZQ,
而在存储过程中 0MroHFh9`
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) uoOUgNwGg
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^e <E/j{~