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。 ACc tyGd
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一、基础 :Ugf3%sQ
1、说明:创建数据库 kZ>_m&g
CREATE DATABASE database-name ))66_bech
2、说明:删除数据库
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drop database dbname ,K
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3、说明:备份sql server 2Jo|]>nl}u
--- 创建 备份数据的 device kNR -eG
USE master F2QFQX(j
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' g]vo."}5E
--- 开始 备份 _Dr9 w&;<
BACKUP DATABASE pubs TO testBack 8BE] A_X
4、说明:创建新表 %|AebxB'o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) jmPnUn
根据已有的表创建新表: ^CO{86V
A:create table tab_new like tab_old (使用旧表创建新表) c#(Hh{0
B:create table tab_new as select col1,col2... from tab_old definition only -Aaim`06bv
5、说明:删除新表 vhIZkz!9
drop table tabname m Q4(<,F
6、说明:增加一个列 ~t^
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Alter table tabname add column col type FUzN}"\1
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。 t-B5,,`
7、说明:添加主键: Alter table tabname add primary key(col) \2)D
说明:删除主键: Alter table tabname drop primary key(col) n+MWny
8、说明:创建索引:create [unique] index idxname on tabname(col....) jVi>9[rz
删除索引:drop index idxname oq${}n <
注:索引是不可更改的,想更改必须删除重新建。 3>M%?d
9、说明:创建视图:create view viewname as select statement 4P jC[A*
删除视图:drop view viewname lonV_Xx
10、说明:几个简单的基本的sql语句 |W_;L6)
选择:select * from table1 where 范围 V^Y'!w\LGI
插入:insert into table1(field1,field2) values(value1,value2) 2[j(C
删除:delete from table1 where 范围 UE8j8U'L
更新:update table1 set field1=value1 where 范围 ~I6N6T Z
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! j 5}'*
排序:select * from table1 order by field1,field2 [desc] 4Hy/K^Ci
总数:select count as totalcount from table1 `OFW^Esc
求和:select sum(field1) as sumvalue from table1 17$'r^t,S
平均:select avg(field1) as avgvalue from table1 jaw&[f
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最大:select max(field1) as maxvalue from table1 M8nfbc^
最小:select min(field1) as minvalue from table1 VKV
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11、说明:几个高级查询运算词 B6=?Qp/f
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A: UNION 运算符 ZtyDip'x
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。 J0V`sK
B: EXCEPT 运算符 k/P.[5
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。 *4/FN TC
C: INTERSECT 运算符 L4,b ThSG
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。 HS[($
注:使用运算词的几个查询结果行必须是一致的。 Q2/65$nW
12、说明:使用外连接 !iO2yp
A、left outer join: $Nd,6w*`
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c sSd/\Ap
B:right outer join: w4(L@1
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 FA%_jM
C:full outer join: E\|nP~;~F9
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 _j+!Fd
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二、提升 {{jV!8wK
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^M{,{bG
法一:select * into b from a where 1<>1 j$K*R."
法二:select top 0 * into b from a AbxhNNK
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) gk6UV2nE?
insert into b(a, b, c) select d,e,f from b; v3#,Z!
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) 8Qo'[+4;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6<EGH*GQ$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. q`,%L1c4
4、说明:子查询(表名1:a 表名2:b) ;$WHTO(
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) nl
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5、说明:显示文章、提交人和最后回复时间 x-"8V(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b g5
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6、说明:外连接查询(表名1:a 表名2:b) 0z'GN#mT5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S=(<m%f
7、说明:在线视图查询(表名1:a ) ia7<AwV
select * from (SELECT a,b,c FROM a) T where t.a > 1; m8ts!6C
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 DmpT<SI+!
select * from table1 where time between time1 and time2 H1I^Vij
select a,b,c, from table1 where a not between 数值1 and 数值2 -8xf}v~u
9、说明:in 的使用方法 Wl |5EY
select * from table1 where a [not] in ('值1','值2','值4','值6') As< B8e]
10、说明:两张关联表,删除主表中已经在副表中没有的信息 d2V X\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) V\o7KF
11、说明:四表联查问题: V:$+$"|
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... RN[I%^$"
12、说明:日程安排提前五分钟提醒 =e4 r=I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |~r-VV(=
13、说明:一条sql 语句搞定数据库分页 T5
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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 tLBtE!J$[
14、说明:前10条记录 #obRr#8
select top 10 * form table1 where 范围 z%OKv[/N
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.) @^xtxtjzux
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1>"-!ADm
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 !bP%\)5
(select a from tableA ) except (select a from tableB) except (select a from tableC) " !~o
17、说明:随机取出10条数据 &E_a0*)e
select top 10 * from tablename order by newid() )P$|9<_q7x
18、说明:随机选择记录 tO&ffZP8$
select newid() v8)"skVnFG
19、说明:删除重复记录 h:nybLw?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) fC[za,PXaE
20、说明:列出数据库里所有的表名 EHk\Q\
select name from sysobjects where type='U' Gq^vto
21、说明:列出表里的所有的 N ~{N Nf Y
select name from syscolumns where id=object_id('TableName') H_X^)\oJ
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。 B1V{3
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 -}#HaL#'K
显示结果: hbJ>GSoZ,
type vender pcs z5kAf~A
电脑 A 1 }5-w,m{8/
电脑 A 1 >#w;67he2
光盘 B 2 /]_ t->
光盘 A 2 <7M-?g:vj
手机 B 3 Y !?'[t
手机 C 3 W6&vyOc
23、说明:初始化表table1 _!nsEG
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TRUNCATE TABLE table1 [ QiG0D_'=
24、说明:选择从10到15的记录 H"#ITL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc f#\YX
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三、技巧 7uF|Z(
1、1=1,1=2的使用,在SQL语句组合时用的较多 <h/%jM>9/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, {~3QBMx6
如: -QrC>3xZR
if @strWhere !='' V)j[`,M:
begin -L1785pB85
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T3X'73M
end Rff F:,b
else wDJ`#"5p{
begin ']r8q %
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ''y.4dvX
end u^1#9bAW8
我们可以直接写成 Xw-[Sf]p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y{p$%
2、收缩数据库 q,vWu(.
--重建索引 uM-,}7f7
DBCC REINDEX or/gx 3
DBCC INDEXDEFRAG zx3gz7>k;
--收缩数据和日志 qN $t_
DBCC SHRINKDB 0cd_l
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DBCC SHRINKFILE ;mkkaW,D*
3、压缩数据库 x HRSzYn$
dbcc shrinkdatabase(dbname) ,`@pi@<"#
4、转移数据库给新用户以已存在用户权限 7?$?Yu
exec sp_change_users_login 'update_one','newname','oldname' j/FLEsU!R
go ={qcDgn~C
5、检查备份集 Zt `Tg7m
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 4:`D3
6、修复数据库 hF%M!otcJ-
ALTER DATABASE [dvbbs] SET SINGLE_USER qt@L&v}~j
GO KK){/I=z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Fx9-A8oIR
GO E/P~HE{
ALTER DATABASE [dvbbs] SET MULTI_USER O>~,RI!
GO i%hCV o
7、日志清除 WsI`!ez;D
SET NOCOUNT ON Cn{Hk)6
DECLARE @LogicalFileName sysname, l":W@R
@MaxMinutes INT, c3$T3Lu1
@NewSize INT mj~:MCC
USE tablename -- 要操作的数据库名 VdLoi\-/L
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 H@Dpht>[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. "Ms;sdjg}&
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0j.K?]f)h
-- Setup / initialize E}@C4pS
DECLARE @OriginalSize int RkF#NCnL;
SELECT @OriginalSize = size >STtX6h
FROM sysfiles jD:
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WHERE name = @LogicalFileName ]A*}Dem*5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Q7BbST+
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + fB+L%+mr8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {& o^p!
FROM sysfiles t" .Ytz>
WHERE name = @LogicalFileName BVQy@:K/
CREATE TABLE DummyTrans D(!^$9e9b
(DummyColumn char (8000) not null) p4`1^}f&Ie
DECLARE @Counter INT, o
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@StartTime DATETIME, : T*Q2
@TruncLog VARCHAR(255) BOs/:ZbK0W
SELECT @StartTime = GETDATE(), Lc3&\q
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @60D@Y
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 2w 2Bc+#o
EXEC (@TruncLog) C]`uC^6g
-- Wrap the log if necessary. *l2`- gbE
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired l/eF
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j4.wd
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AND (@OriginalSize * 8 /1024) > @NewSize +iVEA(0&$
BEGIN -- Outer loop. p"g|]@m
SELECT @Counter = 0 OQVrg2A%(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) }9~^}99}
BEGIN -- update I6>J.6luF9
INSERT DummyTrans VALUES ('Fill Log') RK3 yq$
DELETE DummyTrans $l7^-SK`E
SELECT @Counter = @Counter + 1 8Zv``t61
END uqMw-f/
EXEC (@TruncLog) y.r N(
END (eHyas %X
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Vwkvu&4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nM,:f)z
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6TtB3;5
FROM sysfiles La4S/.
WHERE name = @LogicalFileName v}B%:1P4
DROP TABLE DummyTrans Ve,g9 I
SET NOCOUNT OFF ,g*!NK_:5t
8、说明:更改某个表 S@qp_!
exec sp_changeobjectowner 'tablename','dbo' +>$]leqa
9、存储更改全部表 Q;h.}N8W
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch oMh$:jR $
@OldOwner as NVARCHAR(128), 0RUk^
@NewOwner as NVARCHAR(128) $|K
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AS Knq9"k
DECLARE @Name as NVARCHAR(128) K1&
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DECLARE @Owner as NVARCHAR(128) / f%mYL
DECLARE @OwnerName as NVARCHAR(128) yI0bSu<j-
DECLARE curObject CURSOR FOR 55[ 4)*
select 'Name' = name, _(W@FS
'Owner' = user_name(uid) dG\wW@}J
from sysobjects YeH!v, >
where user_name(uid)=@OldOwner 1W^hPY
order by name y<)TYr
OPEN curObject vOQ%f?%G\
FETCH NEXT FROM curObject INTO @Name, @Owner 8|u4xf<
WHILE(@@FETCH_STATUS=0) Z;BS@e
BEGIN rIyH/=;
if @Owner=@OldOwner ;b~ S/
begin _;lw,;ftA
set @OwnerName = @OldOwner + '.' + rtrim(@Name) tFN >]`Z
exec sp_changeobjectowner @OwnerName, @NewOwner $] 6u#5
end @MW@mP)#
-- select @name,@NewOwner,@OldOwner +-9vrEB
FETCH NEXT FROM curObject INTO @Name, @Owner Q&9yrx.
END P 7x;G5'.
close curObject S-Uod y
deallocate curObject @"@a70WHk
GO .~z'm$s1o
10、SQL SERVER中直接循环写入数据 9shfy4?k
declare @i int ]WT@&F
set @i=1 FG? Mc'r&
while @i<30 la!]Y-s)'4
begin . [|UNg
insert into test (userid) values(@i) SZyk G[
set @i=@i+1 &|yLTx
end 7& M-^Ev
小记存储过程中经常用到的本周,本月,本年函数 {#,<)wFV\
Dateadd(wk,datediff(wk,0,getdate()),-1) }^"6 :;,
Dateadd(wk,datediff(wk,0,getdate()),6) |s8N
Dateadd(mm,datediff(mm,0,getdate()),0) M`MxdwR
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6j#JhcS+
Dateadd(yy,datediff(yy,0,getdate()),0) ,75)
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) *~rj!N?;
上面的SQL代码只是一个时间段 Q
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Dateadd(wk,datediff(wk,0,getdate()),-1) "wUIsuG/p
Dateadd(wk,datediff(wk,0,getdate()),6) 7"(!]+BW!O
就是表示本周时间段. TBlSZZ-55]
下面的SQL的条件部分,就是查询时间段在本周范围内的: _O9V"DM
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rb*|0ST
而在存储过程中 te_2"Z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) VPLf(
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @]\fO)\f