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。 a<k x95
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一、基础 ~gNa<tg"1
1、说明:创建数据库 DBWe>Ef(
CREATE DATABASE database-name /[#<@o
2、说明:删除数据库 n-be8p)-
drop database dbname ]E .+)>
3、说明:备份sql server uLD%M av
--- 创建 备份数据的 device +H,/W_/g
USE master 4GH?$p|LX
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' vrXUS9i.
--- 开始 备份 y
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BACKUP DATABASE pubs TO testBack ycg5S rg
4、说明:创建新表 Vahfz8~w/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) x{`>Il
根据已有的表创建新表: 2>80Qp!xO
A:create table tab_new like tab_old (使用旧表创建新表) %>_ZUu3M
B:create table tab_new as select col1,col2... from tab_old definition only 8%S5Fc#am
5、说明:删除新表 3Kc
drop table tabname 9XImgeAs
6、说明:增加一个列 nsQx\Tnhx
Alter table tabname add column col type R#eY@N}\
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Sc_#BD.
7、说明:添加主键: Alter table tabname add primary key(col) v_3r8My-
说明:删除主键: Alter table tabname drop primary key(col) 7dhip
8、说明:创建索引:create [unique] index idxname on tabname(col....) wWB-P6
删除索引:drop index idxname |_@ '_
注:索引是不可更改的,想更改必须删除重新建。 ;N6Euiz
9、说明:创建视图:create view viewname as select statement '!>LF1W=
删除视图:drop view viewname ~:~-AXaMT
10、说明:几个简单的基本的sql语句 o(Yj[:+m
选择:select * from table1 where 范围 8Ux3,X=
插入:insert into table1(field1,field2) values(value1,value2) >0z(+}]3z
删除:delete from table1 where 范围 )F
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更新:update table1 set field1=value1 where 范围 ^vPM\qP#g
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Ea#wtow|-
排序:select * from table1 order by field1,field2 [desc] MA0}BJoW
总数:select count as totalcount from table1 #!(OTe L
求和:select sum(field1) as sumvalue from table1 sDA&U9;
平均:select avg(field1) as avgvalue from table1 gM~dPM|
最大:select max(field1) as maxvalue from table1 `./$hh
最小:select min(field1) as minvalue from table1 c@!%.# |y
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11、说明:几个高级查询运算词 jI:5[. Y
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A: UNION 运算符 "l0z?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。 's#"~<L^e
B: EXCEPT 运算符 Qz6Ry\u
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。 g*t(%;_m
C: INTERSECT 运算符 1Z-f@PoM
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。 !@j5 yYf
注:使用运算词的几个查询结果行必须是一致的。 xaiA2
12、说明:使用外连接 Hq=5/N
A、left outer join: e
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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。 uXD?s3Wv
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 $}kT)+K
B:right outer join: Fv_rDTo
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 zq\YZ:JC
C:full outer join: "\0&1C(G
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 t0t" =(d
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二、提升 -UD^O*U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 8JYF0r7
法一:select * into b from a where 1<>1 Wl!|+-
法二:select top 0 * into b from a c~j")o
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) x%<oeM3U
insert into b(a, b, c) select d,e,f from b; nSUQ Eho<
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) s'/b&Idf8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 zg)-RCG
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. gzdR|IBa
4、说明:子查询(表名1:a 表名2:b) :mOHR&2xR%
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) FwD"Pc2
5、说明:显示文章、提交人和最后回复时间 T.m*LM
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \jlem <&
6、说明:外连接查询(表名1:a 表名2:b) YXeL7W
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^eu={0k
7、说明:在线视图查询(表名1:a ) Qv~KGd9
select * from (SELECT a,b,c FROM a) T where t.a > 1; )L^GGy8w
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 oUXi4lsSc
select * from table1 where time between time1 and time2 Hrz#S o\#
select a,b,c, from table1 where a not between 数值1 and 数值2 8#?jYhT7
9、说明:in 的使用方法 rK^Sn7 U
select * from table1 where a [not] in ('值1','值2','值4','值6') |Dz$OZP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 sw:o3cC]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) PWU8 9YXp
11、说明:四表联查问题: k{M4.a[(
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 ..... j^ y9+W_b
12、说明:日程安排提前五分钟提醒 RZKdh}B?\
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 vR;?~^{*s
13、说明:一条sql 语句搞定数据库分页 g>g]qQ
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 os<YfMM<:/
14、说明:前10条记录 ="yN4+0-p
select top 10 * form table1 where 范围 2@&|/O6_\h
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.) Q7<_>)e^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (f Gmjx
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 4$HU=]b6Tf
(select a from tableA ) except (select a from tableB) except (select a from tableC) Nd5G-eYI
17、说明:随机取出10条数据 *OoM[wEY
select top 10 * from tablename order by newid() 4<P=wK=a8X
18、说明:随机选择记录 G{wIY" ~4
select newid() R8Kj3wp
19、说明:删除重复记录 S!\4,6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =IbDGw(
20、说明:列出数据库里所有的表名 {xW HKsI>,
select name from sysobjects where type='U' zk#NM"C+
21、说明:列出表里的所有的 %Y0,ww2
select name from syscolumns where id=object_id('TableName') 0[/GEY@
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 G[;GP0\N
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >v
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显示结果: c/K:`XP~
type vender pcs tWT,U[
电脑 A 1 ?W6qwm,?L
电脑 A 1 !xqy6%p
光盘 B 2 E ISgc {s
光盘 A 2 u
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手机 B 3 Z$a5vu*pg
手机 C 3 RB,`I#z1f
23、说明:初始化表table1 +-s$Htx
TRUNCATE TABLE table1 G)(vd0X1
24、说明:选择从10到15的记录 0.MD_s0)>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ( o(, ;
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三、技巧 [osIQ!u;:
1、1=1,1=2的使用,在SQL语句组合时用的较多 ZmXO3,sf)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, E~4d6~s
如: )U2cS\k'7n
if @strWhere !='' y}\d]*5
begin Q+i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 7I#<w[l>k
end 6h?v/\
else 80'!XKSP
begin >TKl`O
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r bfIH":
end Ro2Ab^rQ|
我们可以直接写成 XCN^>ToD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere {E 'go]
2、收缩数据库 =%i~HDiy
--重建索引 e>6NO
DBCC REINDEX VR'R7
DBCC INDEXDEFRAG -;1nv:7Z3
--收缩数据和日志 C6PlO
DBCC SHRINKDB 6T`F'Fk[
DBCC SHRINKFILE -ff@W m
3、压缩数据库 ]ChGi[B~9
dbcc shrinkdatabase(dbname) +46m~" ]
4、转移数据库给新用户以已存在用户权限 \>G :mMk/
exec sp_change_users_login 'update_one','newname','oldname' \nzaF4+$
go ii)DOq#2
5、检查备份集 qr<+@Q
RESTORE VERIFYONLY from disk='E:\dvbbs.bak'
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6、修复数据库 bTd94
ALTER DATABASE [dvbbs] SET SINGLE_USER VoGyjGt&
GO j,Vir"-)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &{R]v/{p]
GO x%`.L6rj
ALTER DATABASE [dvbbs] SET MULTI_USER W3gBLotdg
GO 1y{@fg~..
7、日志清除 32S5Ai@Cd"
SET NOCOUNT ON GV"X) tGo
DECLARE @LogicalFileName sysname, 5*#3v:l/9
@MaxMinutes INT, &OXWD]5$6
@NewSize INT h!!7LPxt
USE tablename -- 要操作的数据库名 4k]DktY}.
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !iHJ!
@MaxMinutes = 10, -- Limit on time allowed to wrap log. .S6u{B
@NewSize = 1 -- 你想设定的日志文件的大小(M) xULcS :Q
-- Setup / initialize r;"uk+{i
DECLARE @OriginalSize int 9^zA(
SELECT @OriginalSize = size I7-6|J@#^
FROM sysfiles FWb`F&
WHERE name = @LogicalFileName T!ik"YZ@i
SELECT 'Original Size of ' + db_name() + ' LOG is ' + TNj WZ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 7,!$lT#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' LvcGh
FROM sysfiles `9vCl@"IV
WHERE name = @LogicalFileName }|-Yd"$
CREATE TABLE DummyTrans ][[\!og
(DummyColumn char (8000) not null) pN-c9n4#j
DECLARE @Counter INT, 0,M1Q~u%.
@StartTime DATETIME, 3x6@::s~
@TruncLog VARCHAR(255) )2Dm{T
SELECT @StartTime = GETDATE(), &`}8Jz=S
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' IPxK$nI^
DBCC SHRINKFILE (@LogicalFileName, @NewSize) K."h}f95
EXEC (@TruncLog) e"u89acp
-- Wrap the log if necessary. [+_0y[~,tB
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;R4qE$u2^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) W>2m%q
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AND (@OriginalSize * 8 /1024) > @NewSize c%O8h
BEGIN -- Outer loop. q*pWx]Y
SELECT @Counter = 0 r)/nx@x
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) w.9'TR
BEGIN -- update {T(z@0Xu
INSERT DummyTrans VALUES ('Fill Log') j%TcW!D-_
DELETE DummyTrans YgCSzW&(
SELECT @Counter = @Counter + 1 jC3)^E@:"
END &LM ^,xx}
EXEC (@TruncLog) laX67Vjv
END dZi?Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !3JYG
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + u^Ss8}d
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' MET"s.v
FROM sysfiles r!WXD9#
WHERE name = @LogicalFileName oHvVZ
DROP TABLE DummyTrans D8r=Vf
SET NOCOUNT OFF ztG!NZL
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' 48t_?2>
9、存储更改全部表 q7-.-k<dQ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch [pgld9To
@OldOwner as NVARCHAR(128), }3xZ`vX[T
@NewOwner as NVARCHAR(128) jn/
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AS Ljq!\D
DECLARE @Name as NVARCHAR(128) S-D=-{@
DECLARE @Owner as NVARCHAR(128) c=Y8R/G<
DECLARE @OwnerName as NVARCHAR(128) d%C:%d
DECLARE curObject CURSOR FOR mok%TK
select 'Name' = name, Or9`E(
'Owner' = user_name(uid) {%cm;o[7o
from sysobjects *M^t@ h l
where user_name(uid)=@OldOwner I[$SVPe#
order by name w\f>.N
OPEN curObject X1GpLy)p
FETCH NEXT FROM curObject INTO @Name, @Owner @*{sj`AS
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WHILE(@@FETCH_STATUS=0) 3.vQ~Fvl
BEGIN 2B<0|EGtzw
if @Owner=@OldOwner <xpHlLc
begin cy+EJq I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) irRe}
exec sp_changeobjectowner @OwnerName, @NewOwner M(+;AS?;
end C6P(86?
-- select @name,@NewOwner,@OldOwner _8;)J
FETCH NEXT FROM curObject INTO @Name, @Owner K,o@~fj
END O"Ua|8
close curObject WI+ 5x
deallocate curObject 3$hbb6N%6.
GO ! !9l@
10、SQL SERVER中直接循环写入数据 nL[zXl
declare @i int zC[lPABQ
set @i=1 tm[e?+Iq
while @i<30 u^{6U(%
begin Pa}B0XBWP
insert into test (userid) values(@i) x22:@Ot6
set @i=@i+1 }[%d=NY
end qp6*v&
小记存储过程中经常用到的本周,本月,本年函数 vKCgtk
Dateadd(wk,datediff(wk,0,getdate()),-1) q%Fc?d9
Dateadd(wk,datediff(wk,0,getdate()),6) !;1$1xWK
Dateadd(mm,datediff(mm,0,getdate()),0) z%pD3J?>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 9^5D28y
Dateadd(yy,datediff(yy,0,getdate()),0) QaMB=wVr
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :?}U Z#
上面的SQL代码只是一个时间段 <m|\#Jw_V
Dateadd(wk,datediff(wk,0,getdate()),-1) W18I"lHeh
Dateadd(wk,datediff(wk,0,getdate()),6) ,& ^vc_}
就是表示本周时间段. xQetAYP`
下面的SQL的条件部分,就是查询时间段在本周范围内的: |8s)kQ4$
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) OSsxO(;g
而在存储过程中 xn)eb#r
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 53w@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U.[?1:v