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。 {+9RJmZg
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一、基础 P<g(i 6]
1、说明:创建数据库 }{R*pmv$bN
CREATE DATABASE database-name NQ`D"n
2、说明:删除数据库 ]5'$EAsuW
drop database dbname 8 m"k3:e^
3、说明:备份sql server 3(c-o0M
--- 创建 备份数据的 device `,]Bs*~
USE master CH6 m
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?xR7Ii3
--- 开始 备份 ^m z9sV
BACKUP DATABASE pubs TO testBack M
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4、说明:创建新表 l.@1]4.
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %o8o~B|{.U
根据已有的表创建新表: 6x^$W ]R
A:create table tab_new like tab_old (使用旧表创建新表) =TD`P et
B:create table tab_new as select col1,col2... from tab_old definition only Z:9 Q~}x8
5、说明:删除新表 vH+g*A0S<
drop table tabname tA#Pc6zBuC
6、说明:增加一个列 :|;@FkQ
Alter table tabname add column col type ^}+\ 52w
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 >._d2.Q'
7、说明:添加主键: Alter table tabname add primary key(col) Uxjc&o
说明:删除主键: Alter table tabname drop primary key(col) -leX|U}k
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q]9$dr=Kk0
删除索引:drop index idxname r *K
注:索引是不可更改的,想更改必须删除重新建。 !JA;0[;l=
9、说明:创建视图:create view viewname as select statement Cu7{>"
删除视图:drop view viewname 529b. |
10、说明:几个简单的基本的sql语句 = Pv_,%
选择:select * from table1 where 范围 ~
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插入:insert into table1(field1,field2) values(value1,value2) y?OP- 27y
删除:delete from table1 where 范围 \:;MFG'
更新:update table1 set field1=value1 where 范围 irQ'Rm[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L('1NN2
排序:select * from table1 order by field1,field2 [desc] CY o
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总数:select count as totalcount from table1 7I;kh`H$(f
求和:select sum(field1) as sumvalue from table1 8 #4K@nm5
平均:select avg(field1) as avgvalue from table1 V|u2(*
最大:select max(field1) as maxvalue from table1 uo`R
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 M">v4f&K1!
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A: UNION 运算符 P3"R2-
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 *
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B: EXCEPT 运算符 vX:}tir[
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 9[qOfIny
C: INTERSECT 运算符 LSta]81B4L
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 D;YfQQr
注:使用运算词的几个查询结果行必须是一致的。 P}4&J ^
12、说明:使用外连接 .HZ d.*
A、left outer join: h,{Q%sqO
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 V&f*+!!2
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C&z!="hMhR
B:right outer join: "L2*RX.R
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 jZ.yt+9
C:full outer join: _ ^FC9
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 SWrTM
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二、提升 ^BF}wQb:j
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) &ZD@-"@
法一:select * into b from a where 1<>1 8xB-cE
法二:select top 0 * into b from a \dHqCQ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) !R@LC
insert into b(a, b, c) select d,e,f from b; gC?}1]9c
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) k'iiRRM
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 J2qsZ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ( 1z"=NCp
4、说明:子查询(表名1:a 表名2:b) ]({-vG\m
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 5qrD~D'
5、说明:显示文章、提交人和最后回复时间 b^HDN(v
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \=0;EI-j
6、说明:外连接查询(表名1:a 表名2:b) ]1++$Ej
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )|*Qs${tF
7、说明:在线视图查询(表名1:a ) d7^
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select * from (SELECT a,b,c FROM a) T where t.a > 1; v_zt$bf{Y
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 q=3>ij{v
select * from table1 where time between time1 and time2 D=ej%]@iw
select a,b,c, from table1 where a not between 数值1 and 数值2 Mqr]e#"o
9、说明:in 的使用方法 3A,N1OXG
select * from table1 where a [not] in ('值1','值2','值4','值6') (}b~}X9
10、说明:两张关联表,删除主表中已经在副表中没有的信息 1>e30Ri,g
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0~U0s3
11、说明:四表联查问题: UIEvwQ
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 ..... c~U0&V_`j
12、说明:日程安排提前五分钟提醒 w>2lG3H<
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "-f]d~P>
13、说明:一条sql 语句搞定数据库分页 $$ND]qM$M
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 /!ElAL
14、说明:前10条记录 $^Xxn.B9
select top 10 * form table1 where 范围 30HUY?'K
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) A"S"La%"
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) L$=R/l
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 M!6Fnj
(select a from tableA ) except (select a from tableB) except (select a from tableC) >n,_Aj
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17、说明:随机取出10条数据 Q+1ot,R
select top 10 * from tablename order by newid() 8fqabR
18、说明:随机选择记录 7(2}Vs!5
select newid() Tu(:?
19、说明:删除重复记录 z<eu=OD4t
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) K#A&
20、说明:列出数据库里所有的表名 <4TI;yy6?
select name from sysobjects where type='U' Y@ v][Q
21、说明:列出表里的所有的 0'd@8]|H
select name from syscolumns where id=object_id('TableName') Vs5 &X+k
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。 [6TI_U~
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 $tu
显示结果: ^X&`YXjuN
type vender pcs |va@&;#wf
电脑 A 1 )#AYb
电脑 A 1 jN+`V)p
光盘 B 2 ).kU7;0
光盘 A 2 x[t?hl=:
手机 B 3 "22./vWV|i
手机 C 3 R"OT&:0/
23、说明:初始化表table1 d_
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TRUNCATE TABLE table1 '5aA+XP|
24、说明:选择从10到15的记录 aX.BaK6I
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KJFQ)#SW!
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三、技巧 |Kd6.Mx
1、1=1,1=2的使用,在SQL语句组合时用的较多 @ fMlbJq
"where 1=1" 是表示选择全部 "where 1=2"全部不选, vE9"1M
如: b#I,Z+0ry
if @strWhere !='' {b- C,J
begin 6Y [&1c8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere s>;"bzzq
end oRd{?I&NY
else >*!T`P}p
begin @Xoh@:j\
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ~jw:4sG
end No\#N/1@P
我们可以直接写成 ( &m1*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 5tv*uz|fv
2、收缩数据库 GYw/KT~$
--重建索引 u|23M,
DBCC REINDEX 8!v|`Ky
DBCC INDEXDEFRAG `x=kb;
--收缩数据和日志 DQhHU1
DBCC SHRINKDB ,;6%s>Cvd(
DBCC SHRINKFILE I&|8
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3、压缩数据库 fp||<B
dbcc shrinkdatabase(dbname) RPa]VL1W
4、转移数据库给新用户以已存在用户权限 M}jl\{
exec sp_change_users_login 'update_one','newname','oldname' TJP;!uX
go 7h9oY<W
5、检查备份集 T2-x 1Sw_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6iQqOAG
6、修复数据库 Yaq0mef0
ALTER DATABASE [dvbbs] SET SINGLE_USER _x5-!gK
GO 2^s@n3t
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NTJ,U2
GO S?t
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ALTER DATABASE [dvbbs] SET MULTI_USER vasw@Uto)
GO toF6 Z
7、日志清除 'NWvQR<X
SET NOCOUNT ON BfCib]V9C
DECLARE @LogicalFileName sysname, =SJ[)|
@MaxMinutes INT, |QzJHP @
@NewSize INT '
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USE tablename -- 要操作的数据库名 h%:wIkZ/
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 a:|]F|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. b c
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@NewSize = 1 -- 你想设定的日志文件的大小(M) y~_x
-- Setup / initialize Bptt"
DECLARE @OriginalSize int h<m>S,@g
SELECT @OriginalSize = size :%Z)u:~':
FROM sysfiles 9F,XjPK=
WHERE name = @LogicalFileName yMNOjs'c {
SELECT 'Original Size of ' + db_name() + ' LOG is ' + j+<!4 0#
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1slt[&4N
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Y\!:/h]E&
FROM sysfiles "~C\Z} ;
WHERE name = @LogicalFileName |RpZr!3V
CREATE TABLE DummyTrans qyyLU@hd
(DummyColumn char (8000) not null) Ahd{f!
DECLARE @Counter INT, M]\"]H?
@StartTime DATETIME, oQyMs> g
@TruncLog VARCHAR(255) T5~Qfl?Y
SELECT @StartTime = GETDATE(), #oGvxc7
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "6$+B/5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g 'L$m|
EXEC (@TruncLog) ^(xVjsHp#
-- Wrap the log if necessary. 7.5\LTM>9e
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 17Q*
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j@Us7Q)A(
AND (@OriginalSize * 8 /1024) > @NewSize nkk GJV!
BEGIN -- Outer loop. suj}A
SELECT @Counter = 0 jaThS!>v
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) t[%=[pJHW
BEGIN -- update QL(}k)dB
INSERT DummyTrans VALUES ('Fill Log') `).;W
DELETE DummyTrans 0txSF^x
SELECT @Counter = @Counter + 1 lSId<v?C>
END x^F2Ywp%
EXEC (@TruncLog) '.&,.E&{$
END y(#F&^|
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hYCyc-W
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + GLl@
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ZG)C#I1;O
FROM sysfiles Jf2:[Mq
WHERE name = @LogicalFileName \No22Je6d
DROP TABLE DummyTrans a7NX~9g
SET NOCOUNT OFF K3UG6S\B
8、说明:更改某个表 Q!%CU8!`&
exec sp_changeobjectowner 'tablename','dbo' I(WND/&
9、存储更改全部表 $PbN=@
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $0iN43WSQ
@OldOwner as NVARCHAR(128), ldoN!J
@NewOwner as NVARCHAR(128) D+_PyK~jc
AS eWx6$_|
DECLARE @Name as NVARCHAR(128) VA'<
DECLARE @Owner as NVARCHAR(128) b OmM~pD
DECLARE @OwnerName as NVARCHAR(128) o9HDxS$~^
DECLARE curObject CURSOR FOR Ll&5#q
select 'Name' = name, +ACV,GG
'Owner' = user_name(uid) ;v+CQx
from sysobjects OEGAwP?F
where user_name(uid)=@OldOwner oB Bdk@
order by name 5p{tt;9[
OPEN curObject WU,72g=
FETCH NEXT FROM curObject INTO @Name, @Owner $t</{]iX
WHILE(@@FETCH_STATUS=0) qXW2a'~
BEGIN 2|w.A!
if @Owner=@OldOwner u&I~%s
begin ~(0Y`+gC
set @OwnerName = @OldOwner + '.' + rtrim(@Name) j'0*|f ^z
exec sp_changeobjectowner @OwnerName, @NewOwner /0YNB)
end vDOeBw=
-- select @name,@NewOwner,@OldOwner IO_H%/v"jC
FETCH NEXT FROM curObject INTO @Name, @Owner 7erao-
END .}y
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close curObject #WpO9[b>
deallocate curObject A8eli=W
GO t@19a6:Co
10、SQL SERVER中直接循环写入数据 nt[0krG
declare @i int " Gn; Q-@
set @i=1 yZ)ScB^
while @i<30 s*#|EdD6@
begin IA!ixabG
insert into test (userid) values(@i) !`#9#T|
set @i=@i+1 WE~3(rs#X#
end N$,)vb<
小记存储过程中经常用到的本周,本月,本年函数 O-2H!58$)
Dateadd(wk,datediff(wk,0,getdate()),-1) ^9b
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Dateadd(wk,datediff(wk,0,getdate()),6) L,4^Of
Dateadd(mm,datediff(mm,0,getdate()),0) R+JI?/H
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) x?<5=,
Dateadd(yy,datediff(yy,0,getdate()),0) IKr7"`
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) gS|xicq!
上面的SQL代码只是一个时间段 }EIwkz8
Dateadd(wk,datediff(wk,0,getdate()),-1) rqh,BkQ0t
Dateadd(wk,datediff(wk,0,getdate()),6) n0i&P9@B1
就是表示本周时间段. FfgJ
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下面的SQL的条件部分,就是查询时间段在本周范围内的: a!^wc,
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) A07P$3>/W
而在存储过程中 +@qk=]3a
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) XP;&iZJ