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。 E1-BB
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一、基础 .8EaFEd
1、说明:创建数据库 z->[:)c
CREATE DATABASE database-name yvp$s
2、说明:删除数据库 U sS"WflB
drop database dbname ~y.t amNW
3、说明:备份sql server eQqx0+-0c
--- 创建 备份数据的 device TcM;6h`
USE master zLda+
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' + =N#6#1
--- 开始 备份 "MNI_C#{
BACKUP DATABASE pubs TO testBack <@z!kl
4、说明:创建新表 HXp$\%A)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) txp^3dZ`^
根据已有的表创建新表: &3_.k
A:create table tab_new like tab_old (使用旧表创建新表) qlgo#[i
B:create table tab_new as select col1,col2... from tab_old definition only p,K]`pt=
5、说明:删除新表 Q=~*oYR
drop table tabname L|H:&|F
6、说明:增加一个列 lqoJ2JMy
Alter table tabname add column col type --chU5
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。 +1o4l i
7、说明:添加主键: Alter table tabname add primary key(col) T>2_ r6;
说明:删除主键: Alter table tabname drop primary key(col) `8sC>)lrwu
8、说明:创建索引:create [unique] index idxname on tabname(col....) kI|7o>}<
删除索引:drop index idxname 3q*p#l~
注:索引是不可更改的,想更改必须删除重新建。 Uop`)
9、说明:创建视图:create view viewname as select statement sOUQd-!"
删除视图:drop view viewname ]Ll<Z
10、说明:几个简单的基本的sql语句 {oK4
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选择:select * from table1 where 范围 |)}&:xA%
插入:insert into table1(field1,field2) values(value1,value2) Ufr,6IX
删除:delete from table1 where 范围 s7>a
更新:update table1 set field1=value1 where 范围 A4>j4\A[M
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! (764-iv(
排序:select * from table1 order by field1,field2 [desc] 82*nC!P3E
总数:select count as totalcount from table1 o3OtG#g2
求和:select sum(field1) as sumvalue from table1 9O2??N7f
平均:select avg(field1) as avgvalue from table1 %ot4$eY
最大:select max(field1) as maxvalue from table1 $4ZjN N@
最小:select min(field1) as minvalue from table1 e"O c
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11、说明:几个高级查询运算词 _(%;O:i
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A: UNION 运算符 r(6$.zx
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。 a
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B: EXCEPT 运算符 D@
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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。 B9h'}460H
C: INTERSECT 运算符 zz_(*0,Qcr
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。 0hr4}FL8
注:使用运算词的几个查询结果行必须是一致的。 %;MM+xVVX
12、说明:使用外连接 _my!YS5n
A、left outer join: sf5 F$
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。 <A`zK
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 V+Y;
B:right outer join: fDD^?/^
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。 P4{!/&/
C:full outer join: 3s
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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。 VSLi{=#
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二、提升 0n-S%e5
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =Hf`yH\#
法一:select * into b from a where 1<>1 M>_
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法二:select top 0 * into b from a RoYwZX~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @h)Z8so
insert into b(a, b, c) select d,e,f from b; O'[r,|Q{
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) }$X/HK
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &X&msEM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. vMv?
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4、说明:子查询(表名1:a 表名2:b) f)#rBAkt
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) w)7 s]Ld
5、说明:显示文章、提交人和最后回复时间 9[,+4&wX7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b q'1
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6、说明:外连接查询(表名1:a 表名2:b) 8ZL9>"%l
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c X(M|T]`b:
7、说明:在线视图查询(表名1:a ) - xKa-3
select * from (SELECT a,b,c FROM a) T where t.a > 1; gPqdl6#c
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 =s/UF _JN
select * from table1 where time between time1 and time2 .h
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select a,b,c, from table1 where a not between 数值1 and 数值2 '<-F3
9、说明:in 的使用方法 'gv~M_
select * from table1 where a [not] in ('值1','值2','值4','值6') y1Op Z
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Cr>YpWm
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Tx:S{n7&
11、说明:四表联查问题: T7#}&>
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ,%<ICusZ
12、说明:日程安排提前五分钟提醒 ZZ2vdy38
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 JS2h/Y$
13、说明:一条sql 语句搞定数据库分页 Zt/4|&w
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 m4x8W2q
14、说明:前10条记录 iOXsj
select top 10 * form table1 where 范围 v4Mn@e_#c
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.) *Eg[@5;QA
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _MxKfah'
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:rzM:BQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) Scd_tw.]|
17、说明:随机取出10条数据 F~;UD<<"H
select top 10 * from tablename order by newid() ":W$$w<
18、说明:随机选择记录 7&w$@zs87
select newid() /5N`Euw
19、说明:删除重复记录 p,K!'\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) JDP /vNq
20、说明:列出数据库里所有的表名 (,^jgv|I
select name from sysobjects where type='U'
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21、说明:列出表里的所有的 _;'<}a
select name from syscolumns where id=object_id('TableName') hF`Qs
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 K'U8ft*_
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 2}0S%R(
显示结果: /vNHb_-
type vender pcs '
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电脑 A 1 2#)z%K6T
电脑 A 1 ioJ|-@!#o
光盘 B 2 #,CK;h9jy!
光盘 A 2 "|nh=!L
手机 B 3 E'+?7ZGWj
手机 C 3 Zonr/sA ~
23、说明:初始化表table1 IutU~%wv
TRUNCATE TABLE table1 /zg|I?$>Z4
24、说明:选择从10到15的记录 mRT$@xa]J
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc -=4{X
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三、技巧 %_.
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1、1=1,1=2的使用,在SQL语句组合时用的较多 %4^NX@1jV
"where 1=1" 是表示选择全部 "where 1=2"全部不选, k7)<3f3&S.
如: 0P l>k'9
if @strWhere !='' F2!]T =
begin ;!pSYcT,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4_W*LG~2s
end )MeeF-Ad6
else O#n=mJ
begin dM)x|b3z
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;5&=I|xqe
end S+7u,%n/
我们可以直接写成 Z3 O_K
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Lq]t6o]
2、收缩数据库 LO@o`JF
--重建索引 bzyy;`;6Q~
DBCC REINDEX 6<Txkk
DBCC INDEXDEFRAG XCj8QM.o
--收缩数据和日志 A@ZsL
DBCC SHRINKDB '#NDR:J"
DBCC SHRINKFILE 2bAH)=
3、压缩数据库 W*~[KdgC
dbcc shrinkdatabase(dbname) o2R&s@%0@B
4、转移数据库给新用户以已存在用户权限 q!y!=hI
exec sp_change_users_login 'update_one','newname','oldname' Nin7AOO
go 89P'WFOFK
5、检查备份集 J936o3F_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' tJII-\3"
6、修复数据库 J0FJ@@
ALTER DATABASE [dvbbs] SET SINGLE_USER L XHDX
GO h@jk3J9^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK j^m x ,
GO N?v}\ PU
ALTER DATABASE [dvbbs] SET MULTI_USER MnTqWC90
GO tQ,3nI!|xF
7、日志清除 gt\*9P
SET NOCOUNT ON tvcM<
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DECLARE @LogicalFileName sysname, D]?yGI_
@MaxMinutes INT, F*p@hl
@NewSize INT mWTV)z57
USE tablename -- 要操作的数据库名 dmPAPCm%y
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 s|D[_N!|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. UId?a}J
@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize $ Gs|Z$(
DECLARE @OriginalSize int cv"Bhql
SELECT @OriginalSize = size JQDS3v=1$
FROM sysfiles z-JYzxL9
WHERE name = @LogicalFileName 'J8Ga<s7C
SELECT 'Original Size of ' + db_name() + ' LOG is ' + n8Rsle`a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `%_(_%K
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?/}-&A"
FROM sysfiles _rz7)%Y'#$
WHERE name = @LogicalFileName Odr<fvV,>
CREATE TABLE DummyTrans 8+Abw)]s
(DummyColumn char (8000) not null) 46D_K
DECLARE @Counter INT, =)f5JwZPG
@StartTime DATETIME, #Q/xQ`+|.
@TruncLog VARCHAR(255) R c
SELECT @StartTime = GETDATE(), 7Cx-yv
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' t/J|<Ooj?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) O{Y*a )"
EXEC (@TruncLog) sI`oz|$
-- Wrap the log if necessary.
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |Ge!;v
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?*:BgaR_
AND (@OriginalSize * 8 /1024) > @NewSize +6s6QeNS8
BEGIN -- Outer loop. ]23+ d/
SELECT @Counter = 0 {w mP
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4^7*R
BEGIN -- update 9a]J Q
INSERT DummyTrans VALUES ('Fill Log') "0m\y+%8
DELETE DummyTrans (l}nwyh5
SELECT @Counter = @Counter + 1 qPn!.m$/
END _-z;
EXEC (@TruncLog) o'=i$Eb
END nZ4@g@e2
SELECT 'Final Size of ' + db_name() + ' LOG is ' + og`g]Z<I
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + LF ;gdF%@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Nt~G
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FROM sysfiles >6:UWvV 1
WHERE name = @LogicalFileName ;R7+6
DROP TABLE DummyTrans UcWf
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SET NOCOUNT OFF ^&\<[\
8、说明:更改某个表 m%U$37A1
exec sp_changeobjectowner 'tablename','dbo' ?i$MinK
9、存储更改全部表 s]Z++Lh<{
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ql7N\COoq
@OldOwner as NVARCHAR(128), t;W'<.m_
@NewOwner as NVARCHAR(128) Cf.(/5X
AS qRCUkw} fs
DECLARE @Name as NVARCHAR(128) YLp#z8 1e
DECLARE @Owner as NVARCHAR(128) }[: i!t.m
DECLARE @OwnerName as NVARCHAR(128) )<`/Aaie
DECLARE curObject CURSOR FOR BHR(B]EI
select 'Name' = name, c>+hY5?C
'Owner' = user_name(uid) +T HBPEq
from sysobjects +kx#"L:
where user_name(uid)=@OldOwner pt%Y1<9Eh?
order by name o"g<Vz
OPEN curObject 6c*QBzNL
FETCH NEXT FROM curObject INTO @Name, @Owner ?'U@oz8 B
WHILE(@@FETCH_STATUS=0) y6&o+;I$[
BEGIN ' pfkbmJ
if @Owner=@OldOwner },,K6*P
begin @Uqcym.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7W=s.Gy7G\
exec sp_changeobjectowner @OwnerName, @NewOwner ?tkd5kE
end t8uaNvUM}e
-- select @name,@NewOwner,@OldOwner vs{xr*Ft
FETCH NEXT FROM curObject INTO @Name, @Owner F@1Eg
END p*|Ct
close curObject 8r.3t\o)X
deallocate curObject QURpg/<U
GO xpWY4Q
10、SQL SERVER中直接循环写入数据 &G_XgQsg{
declare @i int *a' I
set @i=1 G!U
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while @i<30 M<xF4L3]
begin =z#j9'n$@
insert into test (userid) values(@i) g3c,x kaO
set @i=@i+1 Z@bKYfGM
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 A[H"(E#k
Dateadd(wk,datediff(wk,0,getdate()),-1) &,'CHBM
Dateadd(wk,datediff(wk,0,getdate()),6) y|(?>\jBl
Dateadd(mm,datediff(mm,0,getdate()),0) z`!f'I--!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) )OZ
Dateadd(yy,datediff(yy,0,getdate()),0) V-lp';bD
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) +m1*ou'K
上面的SQL代码只是一个时间段 h!
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Dateadd(wk,datediff(wk,0,getdate()),-1) WB\chb%ej#
Dateadd(wk,datediff(wk,0,getdate()),6) ,p6o "-
就是表示本周时间段. gt!tDu
下面的SQL的条件部分,就是查询时间段在本周范围内的: 7w?N-Q$y
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CUx[LZR7m
而在存储过程中 |t_SN,)dd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) w5q'M
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) bEb+oRI