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。 EpS/"adI-!
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一、基础 &qx/ZT
1、说明:创建数据库 H8eEBMGo
CREATE DATABASE database-name WZ'<iI
2、说明:删除数据库 9<gW~
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drop database dbname w){B$X
3、说明:备份sql server LeCc`x,5
--- 创建 备份数据的 device .RroO_H
USE master evyjHc Cx
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Xh8U}w<k6
--- 开始 备份 WsHDIp
BACKUP DATABASE pubs TO testBack xm{?h,U,
4、说明:创建新表 9K$
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sl$6Zv-l%0
根据已有的表创建新表: Ae2N"%Ej
A:create table tab_new like tab_old (使用旧表创建新表) /4;mjE
B:create table tab_new as select col1,col2... from tab_old definition only $n<1D -0!r
5、说明:删除新表 O C&BJNOi
drop table tabname f&vMv.
6、说明:增加一个列 |b\a)1Po:
Alter table tabname add column col type 02,t
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ew\:&"@2]w
7、说明:添加主键: Alter table tabname add primary key(col) 0Z2XVq~T$
说明:删除主键: Alter table tabname drop primary key(col) X5o*8Bg4M
8、说明:创建索引:create [unique] index idxname on tabname(col....) w[GEm,ZC
删除索引:drop index idxname vAM1|,U
注:索引是不可更改的,想更改必须删除重新建。 /4+L2O[
9、说明:创建视图:create view viewname as select statement 8=D,`wog
删除视图:drop view viewname \`y:#N<c
10、说明:几个简单的基本的sql语句 g%J\YRo
选择:select * from table1 where 范围 eBa#Z1Z
插入:insert into table1(field1,field2) values(value1,value2) |M?s[}ll
删除:delete from table1 where 范围 Kb]}p
更新:update table1 set field1=value1 where 范围 ,|*Gr"Q=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Xm# +Z`|N
排序:select * from table1 order by field1,field2 [desc] 4V9BmVS|Th
总数:select count as totalcount from table1 9 m8KDB[N
求和:select sum(field1) as sumvalue from table1 Ko&4{}/
平均:select avg(field1) as avgvalue from table1 W$X/8K bn
最大:select max(field1) as maxvalue from table1 Fug4u?-n
最小:select min(field1) as minvalue from table1 X0L\Ewm
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11、说明:几个高级查询运算词 /,SVG1
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A: UNION 运算符 '`;=d<'
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Z'A 3\f
B: EXCEPT 运算符 qMEd
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 0to`=;JI
C: INTERSECT 运算符 nP[Z6h
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 KC"S06
注:使用运算词的几个查询结果行必须是一致的。 Rk5#5R n
12、说明:使用外连接 -0 xo6'mD
A、left outer join: Zb_A(mnzh
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 2c]751
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c RL&0?OT
B:right outer join: J<L\IP?%
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Y*#xo7#B
C:full outer join: P84YriLo
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 vJs6nVbK
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二、提升 `}`Q qv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0e&&k
法一:select * into b from a where 1<>1 5$!idfDr|m
法二:select top 0 * into b from a ?#a&eW
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) xyo~p,(~t
insert into b(a, b, c) select d,e,f from b; &~;M16XM,e
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) <r <{4\%}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &_]G0~e
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &*o4~6pQ#
4、说明:子查询(表名1:a 表名2:b) !4<D^eh
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) ie[X7$@
5、说明:显示文章、提交人和最后回复时间 =^p}JhQ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 3f$n8>mq
6、说明:外连接查询(表名1:a 表名2:b) X*MK(aV3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4<tbZP3/6)
7、说明:在线视图查询(表名1:a ) X2I_,k'fQ
select * from (SELECT a,b,c FROM a) T where t.a > 1; FO>!T@0G
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 /JRZ?/<1
select * from table1 where time between time1 and time2 vn*K\,
select a,b,c, from table1 where a not between 数值1 and 数值2 ELV~
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9、说明:in 的使用方法 ~-NSIV:f
select * from table1 where a [not] in ('值1','值2','值4','值6') x] `F#5j
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @C^x&Sjm
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oj.J;[-
11、说明:四表联查问题: ]#DCO8Vk
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 ..... y+Nw>\|S
12、说明:日程安排提前五分钟提醒 -rYb{<;ST
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %CYo,
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13、说明:一条sql 语句搞定数据库分页 o"0~
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 1P"{TMd?
14、说明:前10条记录 ";`jS&"=
select top 10 * form table1 where 范围 L'a+1O1q&i
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.) 9;I%Dv
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) a_/4 ^+
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 7xB]Z;:
(select a from tableA ) except (select a from tableB) except (select a from tableC) \>*.+?97
17、说明:随机取出10条数据 A@_>9;
select top 10 * from tablename order by newid() ~9APc{"A
18、说明:随机选择记录 ;X]B0KFe7
select newid() ;=IJHk1&
19、说明:删除重复记录 <sm"3qs"_
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 'hWA&Xx+
20、说明:列出数据库里所有的表名 ` ;mQ"lO
select name from sysobjects where type='U' #hn
21、说明:列出表里的所有的 "9^b1UH<
select name from syscolumns where id=object_id('TableName') d0}(d Gl
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。 K"t?
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 NAtDt=
显示结果: 6wu`;>
type vender pcs >`&2]Wc)
电脑 A 1 )N~ p4kp
电脑 A 1 j7:r8? G
光盘 B 2 \z2y?"\?
光盘 A 2 I+twI&GS
手机 B 3 LHx ")H?,
手机 C 3 2!}F+^8'P
23、说明:初始化表table1 ,6MJW#~]
TRUNCATE TABLE table1 Hmm0H6&u
24、说明:选择从10到15的记录 'MX|=K!C
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !%}n9vr!}\
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三、技巧 9XQE5^
1、1=1,1=2的使用,在SQL语句组合时用的较多 W+u,[_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, -0q|AB<
如: N2 3:+u<)E
if @strWhere !='' A{-S )Z3}
begin fnr8{sr.2Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere OESKLjFt
end
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else h#}w18l
begin x
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' />8A?+g9u
end "3]}V=L<5
我们可以直接写成 \ ;]{`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere toDi70o
2、收缩数据库 ( sl{Rgxe*
--重建索引 zOMxg00
DBCC REINDEX -,;woOG
DBCC INDEXDEFRAG gQSVPbzK
--收缩数据和日志 aB (pdW4
DBCC SHRINKDB ~a3u['B
DBCC SHRINKFILE (O(TFE5^
3、压缩数据库 ~.G$0IJY
dbcc shrinkdatabase(dbname) ^{IZpT3
4、转移数据库给新用户以已存在用户权限 ;u(*&vRqr^
exec sp_change_users_login 'update_one','newname','oldname' T?[;ej:
go vOCaru?~h
5、检查备份集 mX.mX70|J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Xl2g Hh
6、修复数据库 3'6 UvAXFH
ALTER DATABASE [dvbbs] SET SINGLE_USER w[l#0ZZ
GO rxMo7px@}I
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK =$bF[3D
GO NTZ3Np`
ALTER DATABASE [dvbbs] SET MULTI_USER kq(><T
GO F~E)w5?\O
7、日志清除 1Zp/EYWa{
SET NOCOUNT ON E <j=5|0t
DECLARE @LogicalFileName sysname, 6J JA"] `
@MaxMinutes INT, S}h
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@NewSize INT F[O147&C
USE tablename -- 要操作的数据库名 vvY?8/
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5CcX'*P
@MaxMinutes = 10, -- Limit on time allowed to wrap log. _hl| 3
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@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize `EMGrw_
DECLARE @OriginalSize int \fC;b"j
SELECT @OriginalSize = size bG"FN/vg
FROM sysfiles u=s,bt,"5
WHERE name = @LogicalFileName a""9%./B
SELECT 'Original Size of ' + db_name() + ' LOG is ' + DC> R
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + RJ0,7E<B
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Yz[Rl
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FROM sysfiles _8K8Ai-~.>
WHERE name = @LogicalFileName JBw2#ry
CREATE TABLE DummyTrans uA
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(DummyColumn char (8000) not null) Bx}"X?%S
DECLARE @Counter INT, [];wP'*
@StartTime DATETIME, IMdp"
@TruncLog VARCHAR(255) _(gkYJ+MK
SELECT @StartTime = GETDATE(), #
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &,PA+#
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Z>3~n
EXEC (@TruncLog) [ywF!#'){
-- Wrap the log if necessary. Hr}"g@ <
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired WhH60/`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p(I^Y{sGI
AND (@OriginalSize * 8 /1024) > @NewSize Glw|*{$
BEGIN -- Outer loop. MW+DqT.h
SELECT @Counter = 0 S=V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ufi#y<dP
BEGIN -- update @,Dnl v|?
INSERT DummyTrans VALUES ('Fill Log') Z|UVH
DELETE DummyTrans *wmkcifF;
SELECT @Counter = @Counter + 1 't8!.k
END k:~UBs\)(
EXEC (@TruncLog) /o6ido
END 3"0QW4A
SELECT 'Final Size of ' + db_name() + ' LOG is ' + b0h\l#6
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [X@{xF^vBQ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' U,yZ.1V^:
FROM sysfiles }0H<G0
WHERE name = @LogicalFileName S3U]AH)C
DROP TABLE DummyTrans _'V o3b
SET NOCOUNT OFF # Dgkl
8、说明:更改某个表 u w8g%
exec sp_changeobjectowner 'tablename','dbo' pcOi%D,o
9、存储更改全部表 AriV4 +
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1z2v[S&pk
@OldOwner as NVARCHAR(128), IN1n^f$:
@NewOwner as NVARCHAR(128) `hG`}G|^
AS rs>,p)
DECLARE @Name as NVARCHAR(128) T$r/XAs
DECLARE @Owner as NVARCHAR(128) BDPE.8s
DECLARE @OwnerName as NVARCHAR(128) o8E<_rei
DECLARE curObject CURSOR FOR hB\BFVUSn/
select 'Name' = name, d72
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'Owner' = user_name(uid) W6EEC<$JL
from sysobjects twldwuN
where user_name(uid)=@OldOwner !}U3{L-
order by name ^qC.bv]&
OPEN curObject 75R4[C6T
FETCH NEXT FROM curObject INTO @Name, @Owner 3kGg;z6
WHILE(@@FETCH_STATUS=0) }>y~P~`S:
BEGIN !(Y|Vm'
if @Owner=@OldOwner :u=y7[I
begin !7#*Wdt+P
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ]CS
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exec sp_changeobjectowner @OwnerName, @NewOwner =w _T{V
end qa~ju\jm.
-- select @name,@NewOwner,@OldOwner dXY}B=C
FETCH NEXT FROM curObject INTO @Name, @Owner P*?2+.
END r
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close curObject }/NjZ*u
deallocate curObject y<`:I|y
GO $ <[r3
10、SQL SERVER中直接循环写入数据 ;*Y+. ?>a
declare @i int t*BCpC}
set @i=1 *) \y52z
while @i<30 5$Kv%U
begin 3~WI3ZIR
insert into test (userid) values(@i) @*op5qVw
set @i=@i+1 q(s0dkrj
end {t0!N]'
小记存储过程中经常用到的本周,本月,本年函数 !m_y@~pV#u
Dateadd(wk,datediff(wk,0,getdate()),-1) '5T:*Yh
Dateadd(wk,datediff(wk,0,getdate()),6) >c:nr&yP
Dateadd(mm,datediff(mm,0,getdate()),0) F!C<^q~!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Op9+5]XF
Dateadd(yy,datediff(yy,0,getdate()),0) Td^62D;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) id`9,IJx
上面的SQL代码只是一个时间段 V~o'L#a
Dateadd(wk,datediff(wk,0,getdate()),-1) #gf0*:p
Dateadd(wk,datediff(wk,0,getdate()),6) oM#+Z
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就是表示本周时间段. u,YmCEd_V
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~$
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <Z~Nz>'r
而在存储过程中 #>5T,[{?j
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .bh7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) UY.o,I>s