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。 vk.P| Y-;
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一、基础 #VynADPs`o
1、说明:创建数据库 /nB|Fo_&Q
CREATE DATABASE database-name _BHEK
2、说明:删除数据库 ^vha4<'-qG
drop database dbname e]-%P(}Z
3、说明:备份sql server oUx%ra{
--- 创建 备份数据的 device 0Ait7`
USE master M*2
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]'5 G/H5?;
--- 开始 备份 'ZAl7k .
BACKUP DATABASE pubs TO testBack ,v_NrX=f?
4、说明:创建新表 )>I-j$%=2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) W.Z`kH *B
根据已有的表创建新表: U6F1QLSLz
A:create table tab_new like tab_old (使用旧表创建新表) Cxra(!&
B:create table tab_new as select col1,col2... from tab_old definition only "? ON0u9
5、说明:删除新表 3{9d5p|\i
drop table tabname }va>jfy
6、说明:增加一个列 yoG*c%3V?
Alter table tabname add column col type 4}F~h
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 yZkS
7、说明:添加主键: Alter table tabname add primary key(col) {3!E8~
说明:删除主键: Alter table tabname drop primary key(col) t[o_!fmxZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) '^%k TNn
删除索引:drop index idxname ,)ZI&BL5
注:索引是不可更改的,想更改必须删除重新建。 r1/9BTPKdJ
9、说明:创建视图:create view viewname as select statement JsHD3
删除视图:drop view viewname hO; XJyv
10、说明:几个简单的基本的sql语句 &gsBbQ+qA
选择:select * from table1 where 范围 p> g[: ~
插入:insert into table1(field1,field2) values(value1,value2) v W4n>h}]
删除:delete from table1 where 范围 AL;4-(KH
更新:update table1 set field1=value1 where 范围 \gR%PN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! v"-K-AQjB
排序:select * from table1 order by field1,field2 [desc] <h%I-e6
总数:select count as totalcount from table1 0t7vg#v|
求和:select sum(field1) as sumvalue from table1 Z7p!YTA
平均:select avg(field1) as avgvalue from table1 8\Bb7*
最大:select max(field1) as maxvalue from table1 K/M2L&C
最小:select min(field1) as minvalue from table1 A\<W x/
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11、说明:几个高级查询运算词 Go(Td++HS
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A: UNION 运算符 GQ2/3kt
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ym_p49
B: EXCEPT 运算符 tmi)LRF
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 u(i=-PN_<
C: INTERSECT 运算符 i!EAs`$o`
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。 {r'+icvLX
注:使用运算词的几个查询结果行必须是一致的。 X}H?*'-
12、说明:使用外连接 U=PTn(2
A、left outer join: ^@^K
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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。 `T{'ufI4B
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 hlmeT9v{
B:right outer join: @MO/LvD
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。 ><I{R|bC
C:full outer join: lBGYZ--
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。 )6(|A$~C+
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二、提升 yxAy1P;dX
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) EB VG@
法一:select * into b from a where 1<>1 f+1@mGt
法二:select top 0 * into b from a ?AK`M #M
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q _Z+H4
insert into b(a, b, c) select d,e,f from b; </2 aQn
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) O L 9(~p
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 " =6kH,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. nJ h)iQu
4、说明:子查询(表名1:a 表名2:b) 3S"
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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) ,B'fOJ.2
5、说明:显示文章、提交人和最后回复时间 .y<u+)
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |}b~YHTs
6、说明:外连接查询(表名1:a 表名2:b) 7}vI/?r
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c kpXxg: c
7、说明:在线视图查询(表名1:a ) zd/kr
select * from (SELECT a,b,c FROM a) T where t.a > 1; me@)kQ8M
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 KD.|oo
select * from table1 where time between time1 and time2 qA"BoSw 4
select a,b,c, from table1 where a not between 数值1 and 数值2 Q-z `rW
9、说明:in 的使用方法 :W;eW%Y
select * from table1 where a [not] in ('值1','值2','值4','值6') ;Y0M]pC
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~r~YR=
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) iBI->xU[U
11、说明:四表联查问题: Cz
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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 ..... :$0yp`k
12、说明:日程安排提前五分钟提醒 -V-I&sO<
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zwz_K!229
13、说明:一条sql 语句搞定数据库分页 e;g7Ek3n
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 @S:T8
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14、说明:前10条记录 FbRGfHL[
select top 10 * form table1 where 范围 X9ZHYlr+Q
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) tQas_K5
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) KWojMPs
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 +P8CC fPu
(select a from tableA ) except (select a from tableB) except (select a from tableC) )ZI#F]
17、说明:随机取出10条数据 Em !%3C1r
select top 10 * from tablename order by newid() U.X`z3q
18、说明:随机选择记录 `][vaLd`Q
select newid() h,n}=g+?
19、说明:删除重复记录 .+kg1=s
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) S`$%C=a.
20、说明:列出数据库里所有的表名 4XAs^>N+
select name from sysobjects where type='U' V0BT./ B\<
21、说明:列出表里的所有的 D|ra ;d
select name from syscolumns where id=object_id('TableName') (cyvE}g
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。 KIp^|
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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 lX.-qCV"B
显示结果: ,J,Rup">h
type vender pcs NGJst_
电脑 A 1 (T%?@'\
电脑 A 1 eL~3CAV{
光盘 B 2 )[oP`Z
光盘 A 2 b.v +5=)B
手机 B 3 OF03]2j7<|
手机 C 3 }xBDyr63
23、说明:初始化表table1 bN7m[GRO.
TRUNCATE TABLE table1 6VVxpDAi:
24、说明:选择从10到15的记录 (Gw*xsn 1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6Ia HaV+P
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三、技巧 qS9<_if2
1、1=1,1=2的使用,在SQL语句组合时用的较多 D'vaK89\
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 7B=VH r
如: :;eQ*{ `\
if @strWhere !='' WMC\J(@.
begin T0Xm}i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;i\N!T{>
end /(*Ucv2i}T
else Wy}^5]R0E
begin 3E^qh03(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }79O[&
end T~k @Z
我们可以直接写成 Qrt\bz h/}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere DxwR&S{
2、收缩数据库 1ANFhl(l
--重建索引
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DBCC REINDEX :"MHmm=uU8
DBCC INDEXDEFRAG fgeh;cD
--收缩数据和日志
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DBCC SHRINKDB df$.gP
DBCC SHRINKFILE w%s];EE
3、压缩数据库 :L@n(buRN
dbcc shrinkdatabase(dbname) s .<.6t:G4
4、转移数据库给新用户以已存在用户权限 G;flj}z
exec sp_change_users_login 'update_one','newname','oldname' q&J5(9]O|L
go $y&W:
5、检查备份集 8["%e#%`$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^8_yJ=~V
6、修复数据库 n1{[CCee@
ALTER DATABASE [dvbbs] SET SINGLE_USER i@.Tv.NZ
GO 8toOdh
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK sv?Fx;d
GO HE-5e):
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ALTER DATABASE [dvbbs] SET MULTI_USER Ak,JPzT
GO a#"orc j
7、日志清除 '~Cn+xf4]
SET NOCOUNT ON rR :ZTfJs"
DECLARE @LogicalFileName sysname, tT>LOI_z
@MaxMinutes INT, %4),P(4N
@NewSize INT YI
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USE tablename -- 要操作的数据库名 :;.^r,QAI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 D\b$$z]q
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 51b%uz
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y|><Ls6Q
-- Setup / initialize hPSMPbI
DECLARE @OriginalSize int `_)H aF>/
SELECT @OriginalSize = size vQyY
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FROM sysfiles Vx2/^MiXy
WHERE name = @LogicalFileName JPAjOcmU/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + g i6s+2
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L7;~4_M9.V
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' oe] *Q
FROM sysfiles :`zO%h
WHERE name = @LogicalFileName P%lD9<jED
CREATE TABLE DummyTrans s{R,- \_
(DummyColumn char (8000) not null) vhbHt_!u&
DECLARE @Counter INT, 3 a.!9R>
@StartTime DATETIME, \?
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@TruncLog VARCHAR(255) erW2>^My
SELECT @StartTime = GETDATE(), V~[b`&F
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]sqLGmUL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4r7F8*z
EXEC (@TruncLog) rAfz?
-- Wrap the log if necessary. y;Cs#eo
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired F`m}RL]g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) babL.Ua8o
AND (@OriginalSize * 8 /1024) > @NewSize :\P@c(c{^C
BEGIN -- Outer loop. 8
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SELECT @Counter = 0 PVp>L*|BZ;
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) <+g77NL
BEGIN -- update _*6]4\;
INSERT DummyTrans VALUES ('Fill Log') tRJ5IX ##L
DELETE DummyTrans 6vsA8u(|V#
SELECT @Counter = @Counter + 1 eZAMV/]jH
END A~PR
EXEC (@TruncLog) TT/H"Ri}Jp
END tngB;9c+w
SELECT 'Final Size of ' + db_name() + ' LOG is ' + n}.e(z_"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Hs'~)T
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' nH?6o#]N
FROM sysfiles \hgd&H0UU
WHERE name = @LogicalFileName DOJydYds
DROP TABLE DummyTrans 9>w~B|/
SET NOCOUNT OFF 3\@2!:>
8、说明:更改某个表 &Y?t
exec sp_changeobjectowner 'tablename','dbo' 88v8lt;R
9、存储更改全部表 0>Snps3*Z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }+n|0xK
@OldOwner as NVARCHAR(128), h8asj0
@NewOwner as NVARCHAR(128) wpM2{NTP
AS wK-VA$;:
DECLARE @Name as NVARCHAR(128) } 7
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DECLARE @Owner as NVARCHAR(128) 4F|79U #
DECLARE @OwnerName as NVARCHAR(128) @d0f +9d
DECLARE curObject CURSOR FOR 7/IL"
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select 'Name' = name, Q}@t'
'Owner' = user_name(uid) xyL)'C
from sysobjects B#S8j18M
where user_name(uid)=@OldOwner h'-4nu;*
order by name NUYKMo1ze
OPEN curObject (Of6Ij?
FETCH NEXT FROM curObject INTO @Name, @Owner W+!UVUpW
WHILE(@@FETCH_STATUS=0) AE}cHBwZE
BEGIN l; _IH|A
if @Owner=@OldOwner 7j\^h2
begin HK/WO jr
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1v]%FC`
exec sp_changeobjectowner @OwnerName, @NewOwner 49Jnp>h
end H_$?b
-- select @name,@NewOwner,@OldOwner 8l5>t
FETCH NEXT FROM curObject INTO @Name, @Owner 9y*] {IY
END dYrgL3'
close curObject ud`-w
deallocate curObject z;>$["t]6
GO C*b[J
10、SQL SERVER中直接循环写入数据 *uyP+f2O
declare @i int #
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set @i=1 ^qR|lA@=\
while @i<30 4n1g4c-
begin _M`ZF*o=c
insert into test (userid) values(@i) :,0(aB
set @i=@i+1 ~r.R|f]IQ
end (L*GU 7m;
小记存储过程中经常用到的本周,本月,本年函数 ~gd#cL%
Dateadd(wk,datediff(wk,0,getdate()),-1) Y 3ApW vS
Dateadd(wk,datediff(wk,0,getdate()),6) !{.CGpS ]
Dateadd(mm,datediff(mm,0,getdate()),0) {1OxJn1hd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $o?U=
Dateadd(yy,datediff(yy,0,getdate()),0) ae sk.
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2/*u$~
上面的SQL代码只是一个时间段 ":udo VS!
Dateadd(wk,datediff(wk,0,getdate()),-1) `xBoNQai
Dateadd(wk,datediff(wk,0,getdate()),6) p3U)J&]c6
就是表示本周时间段. Rsfb?${0G
下面的SQL的条件部分,就是查询时间段在本周范围内的: M9W
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) r&E gP
而在存储过程中 VhkM{O
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) MT&aH~YB
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |X8?B=