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。 +VOb
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一、基础 h}6_ybmZ
1、说明:创建数据库 tgN92Q.i6T
CREATE DATABASE database-name "iek,Y}j7
2、说明:删除数据库 Z3;=w%W
drop database dbname > V%Q O>C
3、说明:备份sql server h6QWH
--- 创建 备份数据的 device Vyt
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USE master |5ONFde"0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' FdxsUDL
--- 开始 备份 [x_s/"Md;
BACKUP DATABASE pubs TO testBack otq,R6 ^
4、说明:创建新表 l9Pu&M?5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) $9H[3OZPVv
根据已有的表创建新表: jT^!J+?6K+
A:create table tab_new like tab_old (使用旧表创建新表) 0xP:9rm
B:create table tab_new as select col1,col2... from tab_old definition only fN[n>%)VO<
5、说明:删除新表 {j@+h%sF>+
drop table tabname -Enbcz(B
6、说明:增加一个列 jsm0kz
Alter table tabname add column col type P9yw&A
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 V/-MIH7SF
7、说明:添加主键: Alter table tabname add primary key(col) cjT[P"5$
说明:删除主键: Alter table tabname drop primary key(col) sp{j!NSL
8、说明:创建索引:create [unique] index idxname on tabname(col....) `o-*Tr
删除索引:drop index idxname 6\`DlUn'*
注:索引是不可更改的,想更改必须删除重新建。 .mt^m
9、说明:创建视图:create view viewname as select statement z93nYY$`Y
删除视图:drop view viewname ;&mxqY8`'
10、说明:几个简单的基本的sql语句 W-Of[X{<
选择:select * from table1 where 范围 ZNy9_a:dX
插入:insert into table1(field1,field2) values(value1,value2) I9/KM4&
删除:delete from table1 where 范围 jtLnj@,
更新:update table1 set field1=value1 where 范围 ^pw7o6}
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %EIUAG
排序:select * from table1 order by field1,field2 [desc] $rB!Ex{@ac
总数:select count as totalcount from table1 ?`i|"y#
求和:select sum(field1) as sumvalue from table1 j],&z^O$
平均:select avg(field1) as avgvalue from table1 8MQbLj'H
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 ,;3:pr
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11、说明:几个高级查询运算词 1.dX)^\
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A: UNION 运算符 d+1x*`U|
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。 [x$;XqA
B: EXCEPT 运算符 f?m5pax|
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 j4vB`Gr]
C: INTERSECT 运算符 S)Mby
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 .b~OMTHuvM
注:使用运算词的几个查询结果行必须是一致的。 *h])mqhB
12、说明:使用外连接 .h6Y<
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A、left outer join: wRi~Yb?
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 T>5wQYh$'
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 lb95!.av+I
B:right outer join: )<Ob
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。 5~yQ>h
C:full outer join: d'q&Lq
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。 (zEYpTp
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二、提升 2;}xN! 8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) fv/v|
法一:select * into b from a where 1<>1 -s33m]a;
法二:select top 0 * into b from a D:6N9POB
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) C\/b~HU
insert into b(a, b, c) select d,e,f from b; m&ZJqsZIL
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/rcXX7%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ]3 j[3'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. qw)Key
4、说明:子查询(表名1:a 表名2:b) %0 qc@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) x' ?.~
5、说明:显示文章、提交人和最后回复时间 8nf4Jk8r
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \`&xprqAw
6、说明:外连接查询(表名1:a 表名2:b) %cd]xQpCp
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ltl]j*yei
7、说明:在线视图查询(表名1:a ) _rG-#BKW8L
select * from (SELECT a,b,c FROM a) T where t.a > 1; 3U>S]#5}
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 $Uy#/MX
select * from table1 where time between time1 and time2 H!#5!m&
select a,b,c, from table1 where a not between 数值1 and 数值2 A` =]RJ
9、说明:in 的使用方法 %'kX"}N/
select * from table1 where a [not] in ('值1','值2','值4','值6') epYj+T
10、说明:两张关联表,删除主表中已经在副表中没有的信息 sI4QI\*4
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ho>p ^p
11、说明:四表联查问题: [e1\A&T
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 ..... #yX^?+Rc
12、说明:日程安排提前五分钟提醒 jigbeHRy
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 y]MWd#U
13、说明:一条sql 语句搞定数据库分页 [ns&Y0Y`t
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 _3I3AG0e
14、说明:前10条记录 @X|ok*v`
select top 10 * form table1 where 范围 <BQ%8}
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.) (+@faP
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Lq%[A*`^
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 65uZLsQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) -z&9DWH
17、说明:随机取出10条数据 EJv! tyJ\[
select top 10 * from tablename order by newid() ;+r0
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18、说明:随机选择记录 @H3|u`6V
select newid() s~/57S
19、说明:删除重复记录 ;g6 nHek
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) V02309Y
20、说明:列出数据库里所有的表名 &8zk3
select name from sysobjects where type='U' RlPjki"Mg
21、说明:列出表里的所有的 l(.7t'
select name from syscolumns where id=object_id('TableName') YdPlN];[
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。 vW9^hbdx
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 {~ ":;
显示结果: @f-0X1C."N
type vender pcs y B1W>s8&
电脑 A 1 Cx$9#3\
电脑 A 1 ST#PMb'izn
光盘 B 2 h=:*7>}
光盘 A 2 qmQFHC_
手机 B 3 Lax9
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手机 C 3 Qa>%[jx,@,
23、说明:初始化表table1 ozT._C
TRUNCATE TABLE table1 T..-)kL+p
24、说明:选择从10到15的记录 W5TqC
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >Zi|$@7t-
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三、技巧 TeOFAIU
1、1=1,1=2的使用,在SQL语句组合时用的较多 FW/6{tm
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1a \=0=[
如: \?J=mE@;1
if @strWhere !='' _CHKh*KHML
begin 6ch@Be5*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere VOD1xWrb
end qdKh6{
else 7'c8]/qh
begin )kFme=;
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]eY Qio!
end
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我们可以直接写成 :/ ~):tM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v\J!yz
2、收缩数据库 =#7s+ d-
--重建索引 D-;J;m
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DBCC REINDEX AviT+^7E
DBCC INDEXDEFRAG u!sSgx=
--收缩数据和日志 M|5^':Y
DBCC SHRINKDB ^w.k^U=B
DBCC SHRINKFILE SZNFE
3、压缩数据库 ER0TY,
dbcc shrinkdatabase(dbname) 4KN0i
4、转移数据库给新用户以已存在用户权限 A;K{ &x
exec sp_change_users_login 'update_one','newname','oldname' BF@m)w.v
go i(dXA(p
5、检查备份集 aMe%#cLI
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =iA"; x
6、修复数据库 J+-,^8)
ALTER DATABASE [dvbbs] SET SINGLE_USER K+(m'3`
GO c`Lpqs`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK vbW\~xf
GO **"zDY*?W
ALTER DATABASE [dvbbs] SET MULTI_USER 0tn7Rkiw
GO A0'tCq]?0
7、日志清除 cuJ/ Vc
SET NOCOUNT ON gEX:S(1QP
DECLARE @LogicalFileName sysname, qdg= Imx
@MaxMinutes INT, ":5~L9&G
@NewSize INT VKl~oFKXJ
USE tablename -- 要操作的数据库名 HJ2O@e
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 g;|
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. N9~'P-V
@NewSize = 1 -- 你想设定的日志文件的大小(M) +z{x 7
-- Setup / initialize ."$=
DECLARE @OriginalSize int h9@gs,'
SELECT @OriginalSize = size p8E;[
FROM sysfiles kW*W4{Fth
WHERE name = @LogicalFileName sIP6GWK$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + b@UF
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ?#');`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' oZ|{J
FROM sysfiles Xmw2$MCB
WHERE name = @LogicalFileName #)IdJ]
CREATE TABLE DummyTrans f?oI'5R41
(DummyColumn char (8000) not null) L>|A6S#y8/
DECLARE @Counter INT, fh/)di
@StartTime DATETIME, 74</6T]^
@TruncLog VARCHAR(255) |qFN~ !
SELECT @StartTime = GETDATE(), 476M` gA
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >-o?S O(M,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _A# x&<c
EXEC (@TruncLog) GLoL4el
-- Wrap the log if necessary. lBYS>4~
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)
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AND (@OriginalSize * 8 /1024) > @NewSize CVn;RF6
BEGIN -- Outer loop. EV;;N
SELECT @Counter = 0 3M5=@Fwkr
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^$^Vd@t>a
BEGIN -- update `pn-fk
INSERT DummyTrans VALUES ('Fill Log') ixUiXP
DELETE DummyTrans `K ~>!d_
SELECT @Counter = @Counter + 1 #EwRb<'Em
END @idp8J [td
EXEC (@TruncLog) 6r?cpJV{
END U7f#Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + OmQuAG
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + oD|+X/FK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' B@:XC&R^
FROM sysfiles `jl. f
WHERE name = @LogicalFileName jw&}N6^G
DROP TABLE DummyTrans *AJezhR
SET NOCOUNT OFF <{P^W;N7
8、说明:更改某个表 Wl^/=I4p#
exec sp_changeobjectowner 'tablename','dbo' uvAy#,
9、存储更改全部表 QyBK*uNdV
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 9=sMKc%!-
@OldOwner as NVARCHAR(128), lqwJ F &
@NewOwner as NVARCHAR(128) 3vEjf
AS _16&K}<
DECLARE @Name as NVARCHAR(128) ESXU,
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DECLARE @Owner as NVARCHAR(128) ui: >eYv
DECLARE @OwnerName as NVARCHAR(128) }tg:DG
DECLARE curObject CURSOR FOR kgib$t_7
select 'Name' = name, aF_ZV bS
'Owner' = user_name(uid) #6#BSZ E
from sysobjects #gr+%=S'6C
where user_name(uid)=@OldOwner _a:!U^4
order by name s`7
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OPEN curObject =Am*$wGI
FETCH NEXT FROM curObject INTO @Name, @Owner D6@4
WHILE(@@FETCH_STATUS=0) >H]|A<9u(
BEGIN g#bfY=C
if @Owner=@OldOwner 5<>R dLo
begin 5>^ W}0s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) jmwQc&
exec sp_changeobjectowner @OwnerName, @NewOwner ^Xz`hR
end ]((
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-- select @name,@NewOwner,@OldOwner &bRxy`ZH
FETCH NEXT FROM curObject INTO @Name, @Owner % /wP2O<
END uR[PKLh
close curObject GqF.T#|
deallocate curObject rSFXchD/
GO mU0r"\**c3
10、SQL SERVER中直接循环写入数据 4N^Qd3[d
declare @i int &B>uPZ]
set @i=1 I;fw]/M%!
while @i<30 4wEpyQ|L
begin TW;;OS[
insert into test (userid) values(@i) (Os
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set @i=@i+1 D-\'P31
end "YJ;-$rb
小记存储过程中经常用到的本周,本月,本年函数 Hi 0df3t
Dateadd(wk,datediff(wk,0,getdate()),-1) bm]dz;ljh
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) "Z1&z-
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >ehWjL`8
Dateadd(yy,datediff(yy,0,getdate()),0) s9Q)6=mE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %BP)m(S7
上面的SQL代码只是一个时间段 ^zs4tCW %
Dateadd(wk,datediff(wk,0,getdate()),-1) 2$/gg"g+
Dateadd(wk,datediff(wk,0,getdate()),6) dJ"xW;"
就是表示本周时间段.
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下面的SQL的条件部分,就是查询时间段在本周范围内的: 1*Fvx-U'
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) QR-R5XNT[
而在存储过程中 pkMON}"mj
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) I3y4O^?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Bjrv;)XH