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。 l|R<F;|
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一、基础 ain#_H
1、说明:创建数据库 @);!x41f
CREATE DATABASE database-name 73^T*
2、说明:删除数据库 imJ[:E
drop database dbname v&[X&Hu[
3、说明:备份sql server F#!@}K8
--- 创建 备份数据的 device
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USE master hJC
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L&!g33J&
--- 开始 备份 +q`rz
BACKUP DATABASE pubs TO testBack t+W=2w&
4、说明:创建新表 TQOg~lH
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) S:2u3th7
根据已有的表创建新表: `uM0,Z
A:create table tab_new like tab_old (使用旧表创建新表) 6)uPM"cO
B:create table tab_new as select col1,col2... from tab_old definition only KG4#BY&^
5、说明:删除新表 CN8@c!mB
drop table tabname 3$96+A^M *
6、说明:增加一个列 )JY_eG&2Dx
Alter table tabname add column col type ^hl]s?"3
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。 g|v1qfK
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) cKi^C
8、说明:创建索引:create [unique] index idxname on tabname(col....) p ,[XT`q^
删除索引:drop index idxname (^s &M
注:索引是不可更改的,想更改必须删除重新建。 m
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9、说明:创建视图:create view viewname as select statement epGX.
删除视图:drop view viewname zDvP7hl
10、说明:几个简单的基本的sql语句 HX /GLnY/X
选择:select * from table1 where 范围 N SxPN:
插入:insert into table1(field1,field2) values(value1,value2) $tt0D?$4
删除:delete from table1 where 范围 oqd
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更新:update table1 set field1=value1 where 范围 M3jv aI
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! E1{:z"
排序:select * from table1 order by field1,field2 [desc] H/p-YtY
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 xZ S\#{
平均:select avg(field1) as avgvalue from table1 iXG>j.w{79
最大:select max(field1) as maxvalue from table1 B:6sVJ
最小:select min(field1) as minvalue from table1 IQk#
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11、说明:几个高级查询运算词 v8U1uOR,%
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A: UNION 运算符 z[KN^2YS
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 +GYI2
B: EXCEPT 运算符 k8x&aH
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 d=4f`q0k
C: INTERSECT 运算符 8~[C'+r
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 uJ)=+Exii
注:使用运算词的几个查询结果行必须是一致的。 f9l<$l
12、说明:使用外连接 o
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A、left outer join: |peMr#
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。 VhH]n yi7D
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 aaf_3UH.B
B:right outer join: $cJN9|$6
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。 avxn }*:X.
C:full outer join: $ )TF,-#x
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。 ExOB P
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二、提升 Io4:$w
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?lET45'
法一:select * into b from a where 1<>1 G2yUuyAZ
法二:select top 0 * into b from a "{ry 9?z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rlO%%Qn`
insert into b(a, b, c) select d,e,f from b; Dt~}9HrU
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) QIMv9;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 WRcFE<
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \xO2WD
4、说明:子查询(表名1:a 表名2:b) X!+Mgh6
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) |B{$URu
5、说明:显示文章、提交人和最后回复时间 ,5A>:2 zs
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "{ QHWZ
6、说明:外连接查询(表名1:a 表名2:b) Nh\8+v*+{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c DKVt8/vq
7、说明:在线视图查询(表名1:a ) {DXZ}7w:v
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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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 "<.
select * from table1 where time between time1 and time2 5#9Wd9LP
select a,b,c, from table1 where a not between 数值1 and 数值2 &zh+:TRm
9、说明:in 的使用方法 M9 2~iM
select * from table1 where a [not] in ('值1','值2','值4','值6') J!
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10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ad$Qs3)6o
11、说明:四表联查问题: )[M<72
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... %oCjZ"ke
12、说明:日程安排提前五分钟提醒 0h@%q;g
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 dXo'#.
13、说明:一条sql 语句搞定数据库分页 W$t}3Ru
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 6:EH5IO
14、说明:前10条记录 u<y\iZ[
select top 10 * form table1 where 范围 b%!`fn-;
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.) 6P*)rye
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +|"n4iZ!)
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 DN8pJa
(select a from tableA ) except (select a from tableB) except (select a from tableC) &!YH"{b
17、说明:随机取出10条数据 qnfRN'
select top 10 * from tablename order by newid() A%m`LKV~@
18、说明:随机选择记录 J,=E5T}U^
select newid() hTtp-e`
19、说明:删除重复记录 ='bmjXu
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) k+R?JWC:
20、说明:列出数据库里所有的表名 yxP ?O@(
select name from sysobjects where type='U' \lbiz4^>
21、说明:列出表里的所有的 \IZ4( Z
select name from syscolumns where id=object_id('TableName') Tvx8l
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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。 (&]15 FJ$1
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 &G,o guo
显示结果: 6% y)
type vender pcs vS t=Ax3]
电脑 A 1 wCTR-pL^
电脑 A 1 iBiA0 W
光盘 B 2 5B.??;xtaV
光盘 A 2 W7[S7kd
手机 B 3 $9_.Q/9>
手机 C 3 oJ@PJvmR&a
23、说明:初始化表table1 9]F&Fz/G
TRUNCATE TABLE table1 i+x6aQ24
24、说明:选择从10到15的记录 [ 6o:v8&3
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc q\HBAry
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三、技巧 -0r"#48(%
1、1=1,1=2的使用,在SQL语句组合时用的较多 E)_!Hi0<s
"where 1=1" 是表示选择全部 "where 1=2"全部不选, =+-.5M
如: P[P72WR
if @strWhere !='' So 6cm|{
begin [;#.DH]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %^%-h}1
end &CmkNm_B
else GN;XB b]w
begin =i5:*J
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' UuqnL{
end 8kc'|F\
我们可以直接写成 .x$T al
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /~rO2]rZ@
2、收缩数据库 [pWDhY
--重建索引 l/UG+7
DBCC REINDEX 0o=)&%G
DBCC INDEXDEFRAG y{?jr$js<
--收缩数据和日志 JHZo:Ad -&
DBCC SHRINKDB ft qW3VW
DBCC SHRINKFILE R:R@sU
3、压缩数据库 -*q2Y^A^l
dbcc shrinkdatabase(dbname) K ':pU1
4、转移数据库给新用户以已存在用户权限 xAz4ZXj=q
exec sp_change_users_login 'update_one','newname','oldname' J o(}#_y?
go l(#Y8
5、检查备份集 %y\7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' nJ#@W b@
6、修复数据库 E0Y/N?
ALTER DATABASE [dvbbs] SET SINGLE_USER h_G7T1;L
GO (dipKs?K
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,h`D(,?X
GO t RyGxqiG
ALTER DATABASE [dvbbs] SET MULTI_USER 6Vzc:8o>
GO 2,Dc]oj
7、日志清除 /"{ ,m!
SET NOCOUNT ON EF=D}"E6pO
DECLARE @LogicalFileName sysname, RR[TW;
@MaxMinutes INT, bNU^tL3QZ
@NewSize INT ,UZE;lXJ'Q
USE tablename -- 要操作的数据库名 KJC9^BAr
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _po 4(U&
@MaxMinutes = 10, -- Limit on time allowed to wrap log. L"IHyUW
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0fK|}mmZA
-- Setup / initialize KdpJ[[Ug/
DECLARE @OriginalSize int ZL@DD(S-/
SELECT @OriginalSize = size \ g(#)f
FROM sysfiles (*Q|;
WHERE name = @LogicalFileName YY<?w
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^k<$N
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + RWQW/Gwx
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 9k^=m)yS'
FROM sysfiles iC+H;s5<
WHERE name = @LogicalFileName "wC5hj]
CREATE TABLE DummyTrans f4I9H0d;!
(DummyColumn char (8000) not null) HbSx}bM_9
DECLARE @Counter INT, H
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@StartTime DATETIME, o5XUDDi
@TruncLog VARCHAR(255) uPv?Hq
SELECT @StartTime = GETDATE(), SfFR
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ZDmk<}A-U
DBCC SHRINKFILE (@LogicalFileName, @NewSize) R.`J"J0/~
EXEC (@TruncLog) H&IP>8Dk
-- Wrap the log if necessary. :Qp/3(g e
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired v~cW:I
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (4{9
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AND (@OriginalSize * 8 /1024) > @NewSize FN`kSTm*0!
BEGIN -- Outer loop. <sB45sNbU`
SELECT @Counter = 0 qAik$.
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) =F[,-B~
BEGIN -- update km^+
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INSERT DummyTrans VALUES ('Fill Log') =~m"TQv
DELETE DummyTrans #p`7gFl
SELECT @Counter = @Counter + 1 , tj7'c$0
END L^s;kkB
EXEC (@TruncLog) 8J1.(Mwb?
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + \bSHBTK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + IEf^.Z
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' =I}V PxhE7
FROM sysfiles h*Tiv^a
WHERE name = @LogicalFileName {/!Gh\i
DROP TABLE DummyTrans vkgL"([_
SET NOCOUNT OFF Q^w]Nj(e_
8、说明:更改某个表 ?R:Hj=.
exec sp_changeobjectowner 'tablename','dbo' ve^MqW&S
9、存储更改全部表 EC#10.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *~^^A9C8
@OldOwner as NVARCHAR(128), c6)zx
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@NewOwner as NVARCHAR(128) kxwm08/|f
AS 97dI4t<
DECLARE @Name as NVARCHAR(128) /k"P4\P`+Q
DECLARE @Owner as NVARCHAR(128) K!gFD
DECLARE @OwnerName as NVARCHAR(128) s7}
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DECLARE curObject CURSOR FOR Hv*O9!cC
select 'Name' = name, |YFlJ2w
'Owner' = user_name(uid) uhLmyK
from sysobjects bC-x`a@
where user_name(uid)=@OldOwner 2Hwf:S'
order by name a8aqcDs>O
OPEN curObject #8OqX*/
FETCH NEXT FROM curObject INTO @Name, @Owner UQPE )G
WHILE(@@FETCH_STATUS=0) Oh4WYDyT
BEGIN F[Sat;Sll
if @Owner=@OldOwner dtl<
begin ,jcp"-5#j
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ttVSgKAsm
exec sp_changeobjectowner @OwnerName, @NewOwner BIyG[y?qO
end o2jB~}VMl
-- select @name,@NewOwner,@OldOwner '=* 5C{
FETCH NEXT FROM curObject INTO @Name, @Owner Ft!~w#&-
END 59 Y=VS
close curObject 4]KceE
deallocate curObject H4Ek,m|c
GO L1i> %5:g
10、SQL SERVER中直接循环写入数据 )D*xOajo+l
declare @i int h--bN*}H2
set @i=1 HI 61rXNF
while @i<30 7HFO-r118
begin 0eP~F2<bC
insert into test (userid) values(@i) ev
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set @i=@i+1 B ;$8<
end &,7(Wab
小记存储过程中经常用到的本周,本月,本年函数 l}/UriZ0
Dateadd(wk,datediff(wk,0,getdate()),-1) /[5up
Dateadd(wk,datediff(wk,0,getdate()),6) ^umAfk5r?H
Dateadd(mm,datediff(mm,0,getdate()),0) rnE'gH(V'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Su #1yw>
Dateadd(yy,datediff(yy,0,getdate()),0) ek!N eu>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) E5Jk+6EcMa
上面的SQL代码只是一个时间段 Y))sk-
Dateadd(wk,datediff(wk,0,getdate()),-1) vq:j?7
Dateadd(wk,datediff(wk,0,getdate()),6) 6si-IJ
就是表示本周时间段. r
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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: r+u\jZ
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) h zE)>f
而在存储过程中 (5&"Y?#o,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +Ti@M1A&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WpZ^R;eK