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。 8(n>99VVK
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一、基础 `pfgx^qG
1、说明:创建数据库 _kBmKE
CREATE DATABASE database-name n}Z%-w$K#
2、说明:删除数据库 P\dfxR;8%
drop database dbname L<dh\5#p9Y
3、说明:备份sql server pbG-uH^
--- 创建 备份数据的 device N|mggz
USE master }N9PV/a
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %S^ke`MhF
--- 开始 备份 5:38}p9`
BACKUP DATABASE pubs TO testBack pImq<Z
4、说明:创建新表 U`)
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) s>L-0vG
根据已有的表创建新表: <q'?[aKvR
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only ;L:UYhDbUx
5、说明:删除新表 "d-vs t5
drop table tabname z>+CMH5L)
6、说明:增加一个列 F
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Alter table tabname add column col type |m\7/&@<
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。 "
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7、说明:添加主键: Alter table tabname add primary key(col) w)<.v+u.Y
说明:删除主键: Alter table tabname drop primary key(col) =,*/Ph&
8、说明:创建索引:create [unique] index idxname on tabname(col....) . ?#Q(eLj
删除索引:drop index idxname \0lQ1FrY
注:索引是不可更改的,想更改必须删除重新建。 L__{U_p
9、说明:创建视图:create view viewname as select statement -5e8m4*
删除视图:drop view viewname L2Cb/!z`c
10、说明:几个简单的基本的sql语句 !]R>D{""
选择:select * from table1 where 范围 B0RVtbK
插入:insert into table1(field1,field2) values(value1,value2) &u9,|n]O9
删除:delete from table1 where 范围 ipu~T)}
更新:update table1 set field1=value1 where 范围 A
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F+G+XtOS
排序:select * from table1 order by field1,field2 [desc] 9/8+R%
总数:select count as totalcount from table1 ,^CG\);
求和:select sum(field1) as sumvalue from table1 ?ZTA3mV?+
平均:select avg(field1) as avgvalue from table1 Z wKX$(n
最大:select max(field1) as maxvalue from table1 nd\$Y
最小:select min(field1) as minvalue from table1 UK'8cz9
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11、说明:几个高级查询运算词 M.SF}U
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A: UNION 运算符 %a8e_
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 SIM>Lz
B: EXCEPT 运算符 &9gI?b8
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 KY2z)#/
C: INTERSECT 运算符 cC9Zc#aK
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 86KK Y2
注:使用运算词的几个查询结果行必须是一致的。 "WY5Pzsi:
12、说明:使用外连接 vx$DKQK@l\
A、left outer join: L5:1dF
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。 v\(6uej^
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 +bso4 }rS
B:right outer join: fM&
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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。 ) F -8
C:full outer join: wtL=^
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。 Z1$S(p=)L
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二、提升 1e9~):C~W
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) J10 /pS
法一:select * into b from a where 1<>1 3it*l-i\
法二:select top 0 * into b from a ,y0 &E8Z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q(46v`u
insert into b(a, b, c) select d,e,f from b; D
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) %Ze7d&
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 WOgkv(5KN
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Nj?Q{ztS
4、说明:子查询(表名1:a 表名2:b) Ei2M~/
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Q4Wz5n1yp7
5、说明:显示文章、提交人和最后回复时间 sWTa;Qi
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b VeEa17g&
6、说明:外连接查询(表名1:a 表名2:b) )C\/ (
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )`<&~>qp
7、说明:在线视图查询(表名1:a ) a_VWgPVdDS
select * from (SELECT a,b,c FROM a) T where t.a > 1; butBS
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -oZw+ge}
select * from table1 where time between time1 and time2 "Qc4v@~)
select a,b,c, from table1 where a not between 数值1 and 数值2 4K~>
9、说明:in 的使用方法 am'K$s
select * from table1 where a [not] in ('值1','值2','值4','值6') /&qE,>hd.+
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Y HgNL LZ?
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) wKpD++k
11、说明:四表联查问题: mq}uq9<
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 ..... o=zl{tZV
12、说明:日程安排提前五分钟提醒 <}xgp[O
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qs8^qn0A
13、说明:一条sql 语句搞定数据库分页 KAVkYL0
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 ~4#D
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14、说明:前10条记录 M`iE'x
select top 10 * form table1 where 范围 Q`O~ f<a
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.) bO('y@)X
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) );S8`V
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 b"Nd8f[
(select a from tableA ) except (select a from tableB) except (select a from tableC) Rw63{b/
17、说明:随机取出10条数据 zDm3$P=
select top 10 * from tablename order by newid() E&"V~
18、说明:随机选择记录 %<|<%~l&
select newid() n%}#e!
19、说明:删除重复记录 {QN 5QGvK
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Tqs|2at<t
20、说明:列出数据库里所有的表名 J}bLp
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select name from sysobjects where type='U' s[7/w[&
21、说明:列出表里的所有的 (B*,|D[J@i
select name from syscolumns where id=object_id('TableName') 44k8IYC*o
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 oFzmH!&ED
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Fo0s<YlS-
显示结果: SgN?[r)
type vender pcs .Y!dO@$:
电脑 A 1 ]R^xO;g'
电脑 A 1 I4<_y5
光盘 B 2 ZBH^0
光盘 A 2 x*X{*?5@
手机 B 3 AnE]
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手机 C 3 @d0~'_vtB
23、说明:初始化表table1 0a!|*Z
TRUNCATE TABLE table1 W8-vF++R
24、说明:选择从10到15的记录 BNO+-ob-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc X-CoC
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三、技巧 2J)
1、1=1,1=2的使用,在SQL语句组合时用的较多 6@:<62!;
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8wkt9:
如: yr.sfPnJK
if @strWhere !='' Fl(j,B6Z
begin 0\k{v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Lv)1
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end yYTOp^
else +sq_fd ;'D
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X #$l7I9H
end bq8h?Q
我们可以直接写成 QM~~b=P,\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ssH[\i
2、收缩数据库 IO2@^jup
--重建索引 oe=1[9T"
DBCC REINDEX s=K?-O
DBCC INDEXDEFRAG u{sb^cmy
--收缩数据和日志 OeZ"WO
DBCC SHRINKDB h>Z`&
DBCC SHRINKFILE va"bw!zXo*
3、压缩数据库 2P=~6(
dbcc shrinkdatabase(dbname) L{XW2c$h
4、转移数据库给新用户以已存在用户权限 [{>1wJ Pdj
exec sp_change_users_login 'update_one','newname','oldname' u3Zu ~C
go X<v1ES$
5、检查备份集 _1YC9}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =L?2[a$2;
6、修复数据库 ^oE#;aS
ALTER DATABASE [dvbbs] SET SINGLE_USER q(2ZJn13f
GO ?O]RQXsZ2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK \zDs3Hp
GO 5Z:qU{[
ALTER DATABASE [dvbbs] SET MULTI_USER 7^d7:1M
GO \W\*'C8q\
7、日志清除 Bf[`o<c
SET NOCOUNT ON &2ty++gC
DECLARE @LogicalFileName sysname, ;R@D
@MaxMinutes INT, N&$ ,uhmO
@NewSize INT {#pwr WG
USE tablename -- 要操作的数据库名 :FmH=pI!=
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Wn?),=WQ{
@MaxMinutes = 10, -- Limit on time allowed to wrap log. r{*BJi.b
@NewSize = 1 -- 你想设定的日志文件的大小(M) (Y^tky$9
-- Setup / initialize Y%}N@ ,lT
DECLARE @OriginalSize int i
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SELECT @OriginalSize = size H%}/O;C
FROM sysfiles _S-@|9\
WHERE name = @LogicalFileName Qte%<POx+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + QTN'yd?WE
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + s5*HS3D
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' D O||o&u
FROM sysfiles 2,|;qFJY-@
WHERE name = @LogicalFileName ~Jj~W+h
CREATE TABLE DummyTrans Tgbq4xR(
(DummyColumn char (8000) not null) -]n%+,3L
DECLARE @Counter INT, 3kwkU
@StartTime DATETIME, W|s";EAM
@TruncLog VARCHAR(255) }EJ/H3<
SELECT @StartTime = GETDATE(), i;29*"
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' hR.vJ2oa
DBCC SHRINKFILE (@LogicalFileName, @NewSize) zW)Wt.svP
EXEC (@TruncLog) RU>qj
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-- Wrap the log if necessary. _w'_l>I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !*?9n^PaF
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) K(WKx7Kky^
AND (@OriginalSize * 8 /1024) > @NewSize vF[ 4kDHk
BEGIN -- Outer loop. 8f65;lyN
SELECT @Counter = 0 h b8L[ 4
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) y3PrLBTz
BEGIN -- update ;=6EBP%
INSERT DummyTrans VALUES ('Fill Log') ,^DP
DELETE DummyTrans B^ddi
SELECT @Counter = @Counter + 1 3Y&4yIx
END =([4pG
EXEC (@TruncLog) *D9H3M[o#
END _,d<9 Y)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &rl;+QS
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + VC%.u.< F
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $3%+N|L
FROM sysfiles hMV>5Y[s
WHERE name = @LogicalFileName +F2X2e)g"
DROP TABLE DummyTrans |y+_BZ5
SET NOCOUNT OFF 6}|h
8、说明:更改某个表 ~-R2mAUK
exec sp_changeobjectowner 'tablename','dbo' K{B|
9、存储更改全部表 8N3y(y0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch rI6+St
@OldOwner as NVARCHAR(128), O}}rosA
@NewOwner as NVARCHAR(128) qL[SwEc
AS YhC|hDC
DECLARE @Name as NVARCHAR(128) l@-h.tS
DECLARE @Owner as NVARCHAR(128) (=EDqAZg
DECLARE @OwnerName as NVARCHAR(128) f/iMI)J
DECLARE curObject CURSOR FOR ibG>|hV
select 'Name' = name, 1xh7KBr,
'Owner' = user_name(uid) t%<y^Wa=
from sysobjects >[~7fxjK-
where user_name(uid)=@OldOwner Q(e
order by name 8.+
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OPEN curObject {esb"beGLa
FETCH NEXT FROM curObject INTO @Name, @Owner xH}bX- m
WHILE(@@FETCH_STATUS=0) I`i"*z
BEGIN t*u#4I1
if @Owner=@OldOwner :M<] 6o
begin [9#zEURS
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZE~zs~z|
exec sp_changeobjectowner @OwnerName, @NewOwner GQQp(%T
end :F@goiuC
-- select @name,@NewOwner,@OldOwner $J&c1
FETCH NEXT FROM curObject INTO @Name, @Owner hhFO,
END NSH4 @x
close curObject zgH*B*)bj
deallocate curObject 4??LK/s*
GO
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10、SQL SERVER中直接循环写入数据 ^5(d^N
declare @i int 5O
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set @i=1 %/5Wj_|p
while @i<30 _mwt{D2r}
begin M CP GDr
insert into test (userid) values(@i) y\Utm$)j
set @i=@i+1 ()F{kM8
end 1xkrhqq
小记存储过程中经常用到的本周,本月,本年函数 ZmNNR 1%/
Dateadd(wk,datediff(wk,0,getdate()),-1) W8;!rFW
Dateadd(wk,datediff(wk,0,getdate()),6) B;W%P.<.
Dateadd(mm,datediff(mm,0,getdate()),0) jIVD i~Ld
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) .`V$j.a
Dateadd(yy,datediff(yy,0,getdate()),0) U%[ye0@:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) lBAu@M
上面的SQL代码只是一个时间段 nAAv42j[
Dateadd(wk,datediff(wk,0,getdate()),-1) e?*Teb?R
Dateadd(wk,datediff(wk,0,getdate()),6) aql8Or1[
就是表示本周时间段. a(ITv roM/
下面的SQL的条件部分,就是查询时间段在本周范围内的: <gfRAeXA
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) V*@Y9G
而在存储过程中 {IaDZ/XS6
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) '3WtpsKA
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^w2 HF