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。 uB)6\fkTB
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一、基础 laRKt"A
1、说明:创建数据库 (NWN&
CREATE DATABASE database-name e4_aKuA
2、说明:删除数据库 N55=&-p
drop database dbname &oEq&
3、说明:备份sql server i:Ct6[
--- 创建 备份数据的 device ?lw[
USE master @p'v.;~#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' D+U/ ]sW
--- 开始 备份 y&I|m
BACKUP DATABASE pubs TO testBack #$z -]i
4、说明:创建新表 n|`):sP
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %'~<:>:"E
根据已有的表创建新表: ~v,KI["o
A:create table tab_new like tab_old (使用旧表创建新表) Z
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B:create table tab_new as select col1,col2... from tab_old definition only 8`*9jr
5、说明:删除新表 %D6Wlf+^n
drop table tabname ~q%9zO'
6、说明:增加一个列 #RIfR7`T
Alter table tabname add column col type <{).x6
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Z*Hxrw\!0
7、说明:添加主键: Alter table tabname add primary key(col) /gy:#-2Gy
说明:删除主键: Alter table tabname drop primary key(col) _!g
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8、说明:创建索引:create [unique] index idxname on tabname(col....) <TROs!x$a
删除索引:drop index idxname WBIB'2:m
注:索引是不可更改的,想更改必须删除重新建。 Xm[r#IA
9、说明:创建视图:create view viewname as select statement <!nWiwv
删除视图:drop view viewname ->25$5#
10、说明:几个简单的基本的sql语句 XGl13@=O
选择:select * from table1 where 范围 8'\,&f`Y
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 nR'EuI~(}
更新:update table1 set field1=value1 where 范围 \6
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! p$G3r0@
排序:select * from table1 order by field1,field2 [desc] s3RyLT
总数:select count as totalcount from table1 '\mZ7.Jj
求和:select sum(field1) as sumvalue from table1 3#ZKuGg=
平均:select avg(field1) as avgvalue from table1 Ip|^?uyrk
最大:select max(field1) as maxvalue from table1 iOXP\:mPo
最小:select min(field1) as minvalue from table1 $ u.T1v
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11、说明:几个高级查询运算词 m%(JRh
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A: UNION 运算符 `.-k%2?/
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。 [hj'Yg 8{
B: EXCEPT 运算符 Bw7:ry
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。 %((3'le
C: INTERSECT 运算符 K}(n;6\
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_qVk4h\
注:使用运算词的几个查询结果行必须是一致的。 '\YhRU
12、说明:使用外连接 $i]
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A、left outer join: G[-jZ
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 1mPS)X_
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c VCtiZ4
B:right outer join: tf79Gb>
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 )g<qEyJR
C:full outer join: *B}R4Y|g
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 SF=|++b1f
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二、提升 =w?cp}HW
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ur[bh
法一:select * into b from a where 1<>1 H)fo4N4ii
法二:select top 0 * into b from a )_.H #|r
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bUB6B
insert into b(a, b, c) select d,e,f from b; rAdcMFW
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) K'/x9.'%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 F5q1VEe
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <aD+Ki6
4、说明:子查询(表名1:a 表名2:b) | N,nt@~
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) *4VP5]!
5、说明:显示文章、提交人和最后回复时间 gb#wrI
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b LKY
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6、说明:外连接查询(表名1:a 表名2:b) "G)?
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c e(5R8ud
7、说明:在线视图查询(表名1:a ) FMr$cKvE]W
select * from (SELECT a,b,c FROM a) T where t.a > 1; P.J}\;S T
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 U}Fk%Jj
select * from table1 where time between time1 and time2 9'aR-tFun;
select a,b,c, from table1 where a not between 数值1 and 数值2 \Rt
9、说明:in 的使用方法 PelV67?M
select * from table1 where a [not] in ('值1','值2','值4','值6') "n-xsAG
10、说明:两张关联表,删除主表中已经在副表中没有的信息 w2V E_
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) n_2LkW<?
11、说明:四表联查问题: 4rdrl
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 ..... #!@
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12、说明:日程安排提前五分钟提醒 ]qRz!D%@^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 9:~^KQ{?
13、说明:一条sql 语句搞定数据库分页 jzp%.4/j
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 hlEvL
14、说明:前10条记录 5Ozj&Zq
select top 10 * form table1 where 范围 86Vu PV-
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.) B
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) o#b9M4O
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 y
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(select a from tableA ) except (select a from tableB) except (select a from tableC) \bE~iz3b9
17、说明:随机取出10条数据 46`{mPd{aO
select top 10 * from tablename order by newid() a]ey..m
18、说明:随机选择记录 T^>cT"ux_
select newid() kS!*kk*a
19、说明:删除重复记录 zg"ZXZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5%/%i}e~(
20、说明:列出数据库里所有的表名 ArMe[t0$
select name from sysobjects where type='U' GMI>$$<
21、说明:列出表里的所有的 a$A
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select name from syscolumns where id=object_id('TableName') H#akE\,
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。 uBJF}"4ej
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 M-t9zT
显示结果: >8-
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type vender pcs >cLZP#^\2E
电脑 A 1 Yuck]?#0
电脑 A 1 7T78S&g
光盘 B 2 A":x<9
光盘 A 2 `R;XN-
手机 B 3 W;W\L? r
手机 C 3 !;oBvE7Kh
23、说明:初始化表table1 \t3i9#Q
TRUNCATE TABLE table1 wEyh;ID3#
24、说明:选择从10到15的记录 [c~zO+x
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Ado>)c"*y1
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三、技巧 )VrHP9fu
1、1=1,1=2的使用,在SQL语句组合时用的较多 I115Rp0
"where 1=1" 是表示选择全部 "where 1=2"全部不选, *}=W wG
如: +bU(-yRy5o
if @strWhere !='' YTsn;3d]}
begin V#Eq74ic
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere e9nuQ\=
end $:/1U$
else S7]cF5N
begin 0jMrL\>C
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ft7l /
end DoA f,9|_
我们可以直接写成 IFe[3mB5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere -#h
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2、收缩数据库 lU3wIB
--重建索引 0jq#,p=l;
DBCC REINDEX Hr'#0fW
DBCC INDEXDEFRAG mqpZby
--收缩数据和日志 j\<S 6%p#R
DBCC SHRINKDB iFnM6O$(
DBCC SHRINKFILE hw1s^:|+2
3、压缩数据库 8[V!e[
dbcc shrinkdatabase(dbname) 8cl!8gfv
4、转移数据库给新用户以已存在用户权限 }z6HxB]$
exec sp_change_users_login 'update_one','newname','oldname' +{&g|V
go L[efiiLh$
5、检查备份集 2*N# %ZUX
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' '=xl}v
6、修复数据库 3/D fsv
ALTER DATABASE [dvbbs] SET SINGLE_USER 7}MWmS^8j
GO oUH\SW8?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6$Y1[
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER '=5N?)
GO $vd._j&
7、日志清除 0nX5
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SET NOCOUNT ON JT<J[Qz5
DECLARE @LogicalFileName sysname, :Li)]qN.I
@MaxMinutes INT, 2]l*{l^ Bl
@NewSize INT v%r! }s
USE tablename -- 要操作的数据库名 r iz({
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 IdM;N
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \%(R~H
@NewSize = 1 -- 你想设定的日志文件的大小(M) S<44{
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-- Setup / initialize x<" e
DECLARE @OriginalSize int vv3?ewr
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SELECT @OriginalSize = size G.;<?W
FROM sysfiles
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WHERE name = @LogicalFileName - >2ej4C
SELECT 'Original Size of ' + db_name() + ' LOG is ' + se-}d.PwL
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *)Y;`Yg$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' }[|"db
FROM sysfiles BdSTB"
WHERE name = @LogicalFileName K)n( U9#
CREATE TABLE DummyTrans =e63>*M|
(DummyColumn char (8000) not null) +oc}kv,h]
DECLARE @Counter INT, Wr;)3K
@StartTime DATETIME, gS!M7xy
@TruncLog VARCHAR(255) _oWenF
SELECT @StartTime = GETDATE(), Jx_4:G
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @<P[z[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $JOIK9+3z#
EXEC (@TruncLog) @-wAR=k7
-- Wrap the log if necessary. cI H`,bR
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired MFVFr "
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aLr^uce]
AND (@OriginalSize * 8 /1024) > @NewSize jhHb[je~{4
BEGIN -- Outer loop. *GA#.$n
SELECT @Counter = 0 ~0`Pe{^*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Z`[j;=[
BEGIN -- update 0xsvxH"*
INSERT DummyTrans VALUES ('Fill Log') S5;q)qz2J
DELETE DummyTrans db`<E
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SELECT @Counter = @Counter + 1 K_xn>
END B$HQFdTli
EXEC (@TruncLog) 8`+X6iZOQ
END XHW{EVcF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + z-,'W`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 'Mg%G(3
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' l{k
FROM sysfiles 'lWNU
WHERE name = @LogicalFileName ]HRE-g
DROP TABLE DummyTrans 0GB6.Ggft
SET NOCOUNT OFF $*tuv?
8、说明:更改某个表 BD#4=u
exec sp_changeobjectowner 'tablename','dbo' "l!"gc87
9、存储更改全部表 r`5;G4UI
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0 X@5W$x
@OldOwner as NVARCHAR(128), ;@sxE}`?g
@NewOwner as NVARCHAR(128) =%bc;ZUu
AS `ul"D%
DECLARE @Name as NVARCHAR(128) E;N+B34
DECLARE @Owner as NVARCHAR(128) #)XO,^s.
DECLARE @OwnerName as NVARCHAR(128) Cnc77EUD
DECLARE curObject CURSOR FOR MtS$ovg?
select 'Name' = name, Skx TgX5
'Owner' = user_name(uid) ~j UK-E
from sysobjects ?p`}6s Q}
where user_name(uid)=@OldOwner E3`KO'v%
order by name |^FDsJUN
OPEN curObject 1Eg,iTn2*x
FETCH NEXT FROM curObject INTO @Name, @Owner yfV{2[8ux
WHILE(@@FETCH_STATUS=0) gxJ(u{2
BEGIN UHXlBH@
if @Owner=@OldOwner hcej?W8j
begin i;)88
set @OwnerName = @OldOwner + '.' + rtrim(@Name) JjM^\LwKkL
exec sp_changeobjectowner @OwnerName, @NewOwner !
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end W2REwUps
-- select @name,@NewOwner,@OldOwner p_qH7W
FETCH NEXT FROM curObject INTO @Name, @Owner ]TGJ|X
END U5Rzfm4
close curObject }D0j%~&"e
deallocate curObject K^Xg^9
GO $
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10、SQL SERVER中直接循环写入数据 &98qAO]Z
declare @i int F
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set @i=1 ,2u]rLxx;
while @i<30 y:1?~R
begin ow+NT
insert into test (userid) values(@i) /+'@}u
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set @i=@i+1 -5.>9+W8I
end j&8U:Q,
小记存储过程中经常用到的本周,本月,本年函数 B^eea [
Dateadd(wk,datediff(wk,0,getdate()),-1) +1e*>jE
Dateadd(wk,datediff(wk,0,getdate()),6) a29mVmi >
Dateadd(mm,datediff(mm,0,getdate()),0) )U8F6GIC&}
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) MTr _8tI
Dateadd(yy,datediff(yy,0,getdate()),0) qD2<-E&M/
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `,TPd ~#~
上面的SQL代码只是一个时间段 #LF_*a0v
Dateadd(wk,datediff(wk,0,getdate()),-1) 1`b?nX
Dateadd(wk,datediff(wk,0,getdate()),6) 75<E 0O
就是表示本周时间段. G.L4l|%W
下面的SQL的条件部分,就是查询时间段在本周范围内的: hd+JKh!u
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) F/mD05{
而在存储过程中 8amtTM
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) d@`yRueWiV
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9n$$D;