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。 W"!{f
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一、基础 0e +Qn&$#4
1、说明:创建数据库 y9Pw'4R
CREATE DATABASE database-name k
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2、说明:删除数据库 J?Bj=b
drop database dbname 1lYQR`Uh
3、说明:备份sql server L[voouaqm
--- 创建 备份数据的 device \MDhm,H<
USE master K%.t%)A_3
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' MK.TBv
--- 开始 备份 FtW=Cc`hC_
BACKUP DATABASE pubs TO testBack ;$vVYC
4、说明:创建新表 S&F[\4w5]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Df@b;-E
根据已有的表创建新表: G){A&F
A:create table tab_new like tab_old (使用旧表创建新表) OUhlQq\
B:create table tab_new as select col1,col2... from tab_old definition only tISb' ^T
5、说明:删除新表 Nd
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drop table tabname s|][p|
6、说明:增加一个列 d(YAH@
Alter table tabname add column col type kq*IC&y
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。 weMufT
7、说明:添加主键: Alter table tabname add primary key(col) LJSx~)@
说明:删除主键: Alter table tabname drop primary key(col) ]+5Y\~I
8、说明:创建索引:create [unique] index idxname on tabname(col....) l0PXU)>C
删除索引:drop index idxname ,&iEn}xG7i
注:索引是不可更改的,想更改必须删除重新建。 /b]+RXvxj
9、说明:创建视图:create view viewname as select statement #y8Esik
删除视图:drop view viewname |JiN;
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10、说明:几个简单的基本的sql语句 0.wNa~_G|
选择:select * from table1 where 范围 bE!z[j]
插入:insert into table1(field1,field2) values(value1,value2) b63DD(
删除:delete from table1 where 范围 +h? Gps
更新:update table1 set field1=value1 where 范围 ]u.)6{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ky{@*fg.
排序:select * from table1 order by field1,field2 [desc] =d$m@rc0r
总数:select count as totalcount from table1 iU|X/>k?
求和:select sum(field1) as sumvalue from table1 x<5;#
平均:select avg(field1) as avgvalue from table1 4D[(X=FSU
最大:select max(field1) as maxvalue from table1 !jR 1!i
最小:select min(field1) as minvalue from table1 p'kB1)~|
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11、说明:几个高级查询运算词 E~S~Ld%
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A: UNION 运算符 zG7y$\A
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。 swg*fhJFB
B: EXCEPT 运算符 MSb0J `
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。 je74As[
C: INTERSECT 运算符 n){u!z)Al
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。 GG(}#Z5h
注:使用运算词的几个查询结果行必须是一致的。 b?-KC\}v
12、说明:使用外连接 m0*_
A、left outer join: 3
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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。 -+0!Fkt@,
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 &23{(]eO
B:right outer join: geNvp0
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。 &r!jjT
C:full outer join: ~3$:C#"Dl
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。 ^3C%&
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二、提升 z
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G)gPL]C0
法一:select * into b from a where 1<>1 BSY7un+`:
法二:select top 0 * into b from a b~;M&Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {tuGkRY2~
insert into b(a, b, c) select d,e,f from b; pYj}
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) Nkx W*w%}l
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;Ouu+#s
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bLC+73BjC
4、说明:子查询(表名1:a 表名2:b) X
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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) t?FPmbjv
5、说明:显示文章、提交人和最后回复时间 0BN=>]V~j7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Bam 4%G5
6、说明:外连接查询(表名1:a 表名2:b) } DjbVYH
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .G>6_n3
7、说明:在线视图查询(表名1:a ) }O:l]O`
select * from (SELECT a,b,c FROM a) T where t.a > 1; qJK6S4O]
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 "4CO^ B
select * from table1 where time between time1 and time2 rs@qC>_C0
select a,b,c, from table1 where a not between 数值1 and 数值2 `jT1R!$3F
9、说明:in 的使用方法 s-S|#5
select * from table1 where a [not] in ('值1','值2','值4','值6') {'o\#4Wk
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Vah.tOU
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) .c@,$z2M
11、说明:四表联查问题: T*#< p;
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 ..... QKhvP>
12、说明:日程安排提前五分钟提醒 tj: >o#D
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 O*1la/~m
13、说明:一条sql 语句搞定数据库分页 fn.}LeeS>
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 ?e hUGvV2
14、说明:前10条记录 ~t^'4"K*
select top 10 * form table1 where 范围 y<)q;fI7
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.) \P9HAz'6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $kh6-y@
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 )z7+%n TO
(select a from tableA ) except (select a from tableB) except (select a from tableC) \Bn$b2j!%
17、说明:随机取出10条数据 rlkg.e6
select top 10 * from tablename order by newid() =
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18、说明:随机选择记录 +|Mi lwr
select newid() ^ %x7:
19、说明:删除重复记录 7.B]B,]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Cce{aY
20、说明:列出数据库里所有的表名 74a>}+"
select name from sysobjects where type='U' [4HOWM>\
21、说明:列出表里的所有的 ANd#m9(x
select name from syscolumns where id=object_id('TableName') yV5AVMo
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。 L)_L#]Yy
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 !{4bC
显示结果: Q".AmHn
type vender pcs
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电脑 A 1 FhMl+Ou
电脑 A 1 zqb3<WP"
光盘 B 2 WQ1*)h8,9
光盘 A 2 ^/jALA9!
手机 B 3 }"AGX
手机 C 3 E"b"VB
23、说明:初始化表table1 E#,n.U>#)
TRUNCATE TABLE table1 CfjVx
24、说明:选择从10到15的记录 /N`E4bKBR
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lISu[{b?
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三、技巧 )-d&XN7
1、1=1,1=2的使用,在SQL语句组合时用的较多 B#(2,j7M
"where 1=1" 是表示选择全部 "where 1=2"全部不选, mYqRN1%
如: qjd8Q
if @strWhere !='' t5
begin df!n.&\y!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere X"
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end 44_CT?t<
else .p(~/MnO
begin =j !Ruy1
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .{LJ
end LxxFosi8
我们可以直接写成 Fd@:*ER
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ov9kD0S
2、收缩数据库 D[R<H((
--重建索引 xnG,1doa
DBCC REINDEX 3}X; WE `
DBCC INDEXDEFRAG @|J+f5O
--收缩数据和日志 s~Od(,K
DBCC SHRINKDB zmh3
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DBCC SHRINKFILE F#$[jh$
3、压缩数据库 ejC== Fkc
dbcc shrinkdatabase(dbname) X8=sk
4、转移数据库给新用户以已存在用户权限 i3 n0W1~
exec sp_change_users_login 'update_one','newname','oldname' 2j7e@pr
go qlfYX8edZ
5、检查备份集 olO&7jh7|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ]Vgl
6、修复数据库 7nL3+Pq
ALTER DATABASE [dvbbs] SET SINGLE_USER b<mxf\b
GO / =2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]o\y(!
GO YPqp#X*
ALTER DATABASE [dvbbs] SET MULTI_USER rocG;$[
GO e6WKZ~
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7、日志清除
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SET NOCOUNT ON {9C+=v?
DECLARE @LogicalFileName sysname, MPmsW&
@MaxMinutes INT, A1(=7ZKz
@NewSize INT b_T?jCyW
USE tablename -- 要操作的数据库名 fd Rw:K8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =~~Y@eX
@MaxMinutes = 10, -- Limit on time allowed to wrap log. G\:^9!nwY~
@NewSize = 1 -- 你想设定的日志文件的大小(M) QBiLH]qa
-- Setup / initialize &r
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DECLARE @OriginalSize int z`[q$H7?
SELECT @OriginalSize = size ?Em*yc@WD
FROM sysfiles {Jl W1;Jc7
WHERE name = @LogicalFileName -w:F8k ~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + pu +"bq
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + aPMqJ#fIr
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @dj2#
FROM sysfiles P7i
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WHERE name = @LogicalFileName p x1{=~V/
CREATE TABLE DummyTrans ^N5BJ'[F:
(DummyColumn char (8000) not null) H#B~h4#
DECLARE @Counter INT, RuHMD"
@StartTime DATETIME, <H)I06];
@TruncLog VARCHAR(255) x\Det$3Kx
SELECT @StartTime = GETDATE(), r{gJ[%
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) S@a#,,\[
EXEC (@TruncLog) $G5;y>
-- Wrap the log if necessary. yprf
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tj_+0J$sw:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) &[hq !v
AND (@OriginalSize * 8 /1024) > @NewSize w3=Bj
BEGIN -- Outer loop. $MEKt}S
SELECT @Counter = 0 e)~7pXYV)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) t%n3~i4X:
BEGIN -- update 0?",dTf3i
INSERT DummyTrans VALUES ('Fill Log') wcT0XXh
DELETE DummyTrans \e/'d~F
SELECT @Counter = @Counter + 1 9j[%Y?
END t$z
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EXEC (@TruncLog) 6NV- &0 _
END P#g"c.?;
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ^p0BeSRiy;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + FasA f(3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {yy^DlHb
FROM sysfiles "s]c79t
WHERE name = @LogicalFileName bX:ARe
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DROP TABLE DummyTrans ^< ,Np+
SET NOCOUNT OFF Jk)^6
8、说明:更改某个表 $#dPM*E
exec sp_changeobjectowner 'tablename','dbo' q=5#t~?
9、存储更改全部表 +FWkhmTv
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Gv!*
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@OldOwner as NVARCHAR(128), ~$N%UQn?b#
@NewOwner as NVARCHAR(128) ~5HI9A4^
AS }7Si2S
DECLARE @Name as NVARCHAR(128) 1X4v:rI
DECLARE @Owner as NVARCHAR(128) 1CiK&fQ'
DECLARE @OwnerName as NVARCHAR(128) *FkG32k
DECLARE curObject CURSOR FOR | 1Fy
select 'Name' = name, PEPBnBA&1
'Owner' = user_name(uid) mlR*S<Z
from sysobjects !TRJsL8
where user_name(uid)=@OldOwner a r#p7N
order by name eyZ /%4'q
OPEN curObject 7mSVL\\^
FETCH NEXT FROM curObject INTO @Name, @Owner Elt=/,v`!
WHILE(@@FETCH_STATUS=0) >Rw[ x
BEGIN f!~gfnn
if @Owner=@OldOwner =>Vo|LBoe
begin &P%3'c}G
set @OwnerName = @OldOwner + '.' + rtrim(@Name) vv
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exec sp_changeobjectowner @OwnerName, @NewOwner 1FS Jqad
end \k1psqw^O
-- select @name,@NewOwner,@OldOwner J(0.eD91v
FETCH NEXT FROM curObject INTO @Name, @Owner h$p]#]uMb
END H[guJ)4#@
close curObject ;/W;M> ^
deallocate curObject (63_
GO FLO#!G
10、SQL SERVER中直接循环写入数据 )k0P' zGb
declare @i int *f:^6h
set @i=1 bmotR8d
while @i<30 &UUIiQm~
begin CUT D]:\
insert into test (userid) values(@i) "SyAOOZ
set @i=@i+1 cjU*
end
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小记存储过程中经常用到的本周,本月,本年函数 DKCPi 0
Dateadd(wk,datediff(wk,0,getdate()),-1) \FSkI0
Dateadd(wk,datediff(wk,0,getdate()),6) euS"C*
Dateadd(mm,datediff(mm,0,getdate()),0) (xJ6: u
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) aD,sx#g0
Dateadd(yy,datediff(yy,0,getdate()),0) kScq#<Y&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ,
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上面的SQL代码只是一个时间段 ]l>)Di#*o
Dateadd(wk,datediff(wk,0,getdate()),-1) 8/f,B:by
Dateadd(wk,datediff(wk,0,getdate()),6) ^o]ZDc
就是表示本周时间段. KvC`6
下面的SQL的条件部分,就是查询时间段在本周范围内的: udDhJ?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) nsqs*$
而在存储过程中 N.C<Mo
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) zR/d:P?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) >C~-*M9