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。 AN:@fZ
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一、基础 -C7]qbT
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1、说明:创建数据库 zW |=2oX2
CREATE DATABASE database-name lG<hlYckv
2、说明:删除数据库 I,6/21kO
drop database dbname p4u5mM
3、说明:备份sql server "I-
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--- 创建 备份数据的 device ,38Eq`5&W
USE master Tsb{25`+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'fwU]Hm
--- 开始 备份 n_D8JF
BACKUP DATABASE pubs TO testBack VzS&`d.h
4、说明:创建新表 @gGRm
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L];y}]:F*
根据已有的表创建新表: 'WyTI^K9
A:create table tab_new like tab_old (使用旧表创建新表) ?wpB`
B:create table tab_new as select col1,col2... from tab_old definition only ^,Ydr~|T
5、说明:删除新表 0"k|H&
drop table tabname {4 >mc'dv
6、说明:增加一个列 bEuaOBc
Alter table tabname add column col type E9!N>0
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。 s=I'e/"7
7、说明:添加主键: Alter table tabname add primary key(col) \g)Xt?w0Wo
说明:删除主键: Alter table tabname drop primary key(col) RH;:9_*F
8、说明:创建索引:create [unique] index idxname on tabname(col....) 0pe3L
删除索引:drop index idxname +0z 7KO%^^
注:索引是不可更改的,想更改必须删除重新建。 d?,M/$h
9、说明:创建视图:create view viewname as select statement _+f+`]iM
删除视图:drop view viewname D]! aT+
10、说明:几个简单的基本的sql语句 6"j_iB
选择:select * from table1 where 范围 {.e=qQ%P5)
插入:insert into table1(field1,field2) values(value1,value2) :q##fG'm/
删除:delete from table1 where 范围 woH)0v
更新:update table1 set field1=value1 where 范围 =/Aj
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %T`U^Pnr
排序:select * from table1 order by field1,field2 [desc] s0UFym8
总数:select count as totalcount from table1 qd@&59zSh
求和:select sum(field1) as sumvalue from table1 )4Q?aMm
平均:select avg(field1) as avgvalue from table1 |w}w.%
最大:select max(field1) as maxvalue from table1 6`01EIk
最小:select min(field1) as minvalue from table1 /G{_7cb
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11、说明:几个高级查询运算词 [V#r7a
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A: UNION 运算符 Y o0FUj
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。 .~lKBkS`!
B: EXCEPT 运算符 jLg@FDb~
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。 u9-nt}hGYM
C: INTERSECT 运算符 6&v?)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。 }`_@'4:t
注:使用运算词的几个查询结果行必须是一致的。 -PB[-CX
12、说明:使用外连接 [^H"FA[
A、left outer join: w&&2H8
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。 ][PzgzG
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 ~o3Hdd_#}N
B:right outer join: C}g9'jY
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。 }7<5hn E
C:full outer join: Zwt; d5U
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。 D6D1S/:ij'
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二、提升 6Q|k7*,B
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >v;8~pgO
法一:select * into b from a where 1<>1 :y]Omp
法二:select top 0 * into b from a )+I.|5g
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ZBD;a;wx
insert into b(a, b, c) select d,e,f from b; R_P}~l
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) &Jc_Fc(M
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 -XoP ia2
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ytEC
4、说明:子查询(表名1:a 表名2:b) GDaN
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) ^[:9fs
5、说明:显示文章、提交人和最后回复时间 wl=61Mb
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b -OZ 5vH0
6、说明:外连接查询(表名1:a 表名2:b) ^:, l\Y
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c RH0>ZZR
7、说明:在线视图查询(表名1:a ) c2l_$p
select * from (SELECT a,b,c FROM a) T where t.a > 1; i yYJR
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 mbl]>JsQD
select * from table1 where time between time1 and time2 ,n,RFa
select a,b,c, from table1 where a not between 数值1 and 数值2 I 1d0iU
9、说明:in 的使用方法 yKagT$-
select * from table1 where a [not] in ('值1','值2','值4','值6') W3W'oo
10、说明:两张关联表,删除主表中已经在副表中没有的信息 }`VDD?M
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <c[U#KrvJ
11、说明:四表联查问题: wHjLd$ +o
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 ..... !#ri5{od
12、说明:日程安排提前五分钟提醒 =Yo1v=wxN
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 eS/B24;*
13、说明:一条sql 语句搞定数据库分页 {X]R-1>
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 9V uq,dv
14、说明:前10条记录 pC,o2~%{
select top 10 * form table1 where 范围 3{%LS"c
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.) 59uwB('|lH
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) RNVbcd
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 `D7C?M#j]
(select a from tableA ) except (select a from tableB) except (select a from tableC) ewNz%_2
17、说明:随机取出10条数据 :!&;p
select top 10 * from tablename order by newid() dth&?/MERL
18、说明:随机选择记录 zZ-wG
select newid() ;.sl*q1A
19、说明:删除重复记录 }0hL~i
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) N<|$h5isq
20、说明:列出数据库里所有的表名 ^(}585b
select name from sysobjects where type='U' @*N)i?>
21、说明:列出表里的所有的 ]Hj<IvG
select name from syscolumns where id=object_id('TableName') 9ch#}/7B
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。 %b.UPS@I
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 q}Z3?W
显示结果: 8{U-m0v
type vender pcs FxG7Pk+=
电脑 A 1 6Z?j AXGSq
电脑 A 1 Z!xVgM{
光盘 B 2 |xr%6 [Ff
光盘 A 2 n@C~ev@%S
手机 B 3 _;A $C(
手机 C 3 ~Aad9yyi
23、说明:初始化表table1 Nb2Qp
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TRUNCATE TABLE table1 9&%fq)gS
24、说明:选择从10到15的记录 fJ*:{48
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc hw_JDv+
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三、技巧 u.pxz8
1、1=1,1=2的使用,在SQL语句组合时用的较多 xynw8;Y,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0XwHP{XaO
如: :A46~UA!$
if @strWhere !='' 5pNY)>]t=
begin '+'CbWgY
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere jkAAqR R
end a>4uiFiv
else ( fD
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begin 'J*<iA*W
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' BIaDY<j90
end ln*icaDqf
我们可以直接写成 ~sQjl]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?zJpD8e
2、收缩数据库 fqz28aHh
--重建索引 C`rLj5E%
DBCC REINDEX Oh.ZPG=
DBCC INDEXDEFRAG *x~xWg9^
--收缩数据和日志 1RLY $M
DBCC SHRINKDB #yseiVm;
DBCC SHRINKFILE Hs"(@eDV&J
3、压缩数据库 6TWWlU^e
dbcc shrinkdatabase(dbname) 5 v^yQ<70
4、转移数据库给新用户以已存在用户权限 $!vxVs9n
exec sp_change_users_login 'update_one','newname','oldname' I|oT0y&
go 31^cz*V
5、检查备份集 <q)4la
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6Q4X6U:WB
6、修复数据库 T&Xl'=/
ALTER DATABASE [dvbbs] SET SINGLE_USER >>l`,+y
GO qpoV]#iW
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK %x;x_
GO |9xI_(+{kP
ALTER DATABASE [dvbbs] SET MULTI_USER z_;3H,z`
GO ";[iZ
7、日志清除 v4Zb?
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SET NOCOUNT ON }g+;y
DECLARE @LogicalFileName sysname, P47V:E%
@MaxMinutes INT, @ufo$?D
@NewSize INT [@<sFP;g
USE tablename -- 要操作的数据库名 >$67 7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 DVZdClAL
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >!e<}84b
@NewSize = 1 -- 你想设定的日志文件的大小(M) c97{Pu
-- Setup / initialize uaw~r2
DECLARE @OriginalSize int ?[TfpAtQ`
SELECT @OriginalSize = size dCYCHHHF
FROM sysfiles Zt
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WHERE name = @LogicalFileName dBsX*}C
SELECT 'Original Size of ' + db_name() + ' LOG is ' + h[KvhbD3
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 7T``-:`[
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' cxeghy:;U
FROM sysfiles 3:/'t{ ^B
WHERE name = @LogicalFileName xVB;s.'!
CREATE TABLE DummyTrans gC%G;-gm
(DummyColumn char (8000) not null) Agh`]XQ2
DECLARE @Counter INT, 4nfu6Dq
@StartTime DATETIME, h<<>3 A
@TruncLog VARCHAR(255) #mR4fst
SELECT @StartTime = GETDATE(), Mk<Vydds
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2N#$X'8
DBCC SHRINKFILE (@LogicalFileName, @NewSize) #T K~eHi
EXEC (@TruncLog) BC>=B@H0
-- Wrap the log if necessary. |!|^ v
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ! hd</_#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) s1Ok|31|
AND (@OriginalSize * 8 /1024) > @NewSize Bm$"WbOq*R
BEGIN -- Outer loop. A$0H
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SELECT @Counter = 0 j!~l,::$"X
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Kyt)2p
BEGIN -- update &K_)#v`|
INSERT DummyTrans VALUES ('Fill Log') Tl]e%A`|
DELETE DummyTrans vD/NgRBww
SELECT @Counter = @Counter + 1 nL@KX>
END M4LP$N
EXEC (@TruncLog) 0l*]L`]L#
END w1x"
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + '# NcZy
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + k-V,~c
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~9^)wCM+
FROM sysfiles rVvR!"//yH
WHERE name = @LogicalFileName 5hj
DROP TABLE DummyTrans VpfUm?Nq
SET NOCOUNT OFF U/ V
8、说明:更改某个表 {%)s.5Pfw
exec sp_changeobjectowner 'tablename','dbo' [%~
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9、存储更改全部表 I3 =#@2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch X5fmz%VK@
@OldOwner as NVARCHAR(128), HjvCujJ
@NewOwner as NVARCHAR(128) RpG+>"1]
AS mOpTzg@
DECLARE @Name as NVARCHAR(128) _iKq~\v2
DECLARE @Owner as NVARCHAR(128) HD,xY4q&N
DECLARE @OwnerName as NVARCHAR(128) .Ig+Dj{)
DECLARE curObject CURSOR FOR +h^jC9,m~{
select 'Name' = name, mE O\r|A
'Owner' = user_name(uid) wS+V]`b
from sysobjects <H3ezv1M
where user_name(uid)=@OldOwner q/3ziVd7p
order by name ,jA)wJ
OPEN curObject R2etB*k6[
FETCH NEXT FROM curObject INTO @Name, @Owner k 4/D8(OXw
WHILE(@@FETCH_STATUS=0) 0tISXu-
BEGIN d\MLOXnLq;
if @Owner=@OldOwner "xcX'F^
begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) m^' uipa\
exec sp_changeobjectowner @OwnerName, @NewOwner !g~1&Uw1
end 5Dp#u
-- select @name,@NewOwner,@OldOwner =4uSFK_L
FETCH NEXT FROM curObject INTO @Name, @Owner AIb2k
END 1XG!$4DW
close curObject OJT1d-5p
deallocate curObject YzosZ! L!<
GO 4p%A8%/q
10、SQL SERVER中直接循环写入数据 bn
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declare @i int J{ [n?/A{
set @i=1 QY/hI`
while @i<30 DU%w1+u
begin 1}hIW":3Sr
insert into test (userid) values(@i) 4v
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set @i=@i+1 ~/NKw:
end A,su;Qh
小记存储过程中经常用到的本周,本月,本年函数 i'd2[A.7I
Dateadd(wk,datediff(wk,0,getdate()),-1) KKA~#iCk
Dateadd(wk,datediff(wk,0,getdate()),6) f~E*Zz`;
Dateadd(mm,datediff(mm,0,getdate()),0) Vc^HVyAx@n
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $VAx:Y|
Dateadd(yy,datediff(yy,0,getdate()),0) $'W}aER
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) &aM7T_h8
上面的SQL代码只是一个时间段 GdB.4s^
Dateadd(wk,datediff(wk,0,getdate()),-1) _'4A|-9
Dateadd(wk,datediff(wk,0,getdate()),6) NmK8<9`u
就是表示本周时间段. 01!s"wjf
下面的SQL的条件部分,就是查询时间段在本周范围内的: V)Z70J<'
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d]9U^iy
而在存储过程中 Iff9'TE
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) '65LKD
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) I%|>2}-_U