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。 &[ejxK"
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一、基础 o5)lTVQ~~
1、说明:创建数据库 sr1 `/
CREATE DATABASE database-name B%QvFxZz
2、说明:删除数据库 :^]rjy/|+
drop database dbname E
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3、说明:备份sql server b"n0Yk1
--- 创建 备份数据的 device H`|8x4
USE master {Hg.ctam
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i_8v >F
--- 开始 备份 97;`R[^J
BACKUP DATABASE pubs TO testBack NK.] yw'
4、说明:创建新表 D#R5G
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) qC]6g
根据已有的表创建新表: X<{kf-GP
A:create table tab_new like tab_old (使用旧表创建新表) -,+zA.{+W
B:create table tab_new as select col1,col2... from tab_old definition only (
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5、说明:删除新表 1\K%^<QY
drop table tabname ] }XsP
6、说明:增加一个列 y5gTd_-
Alter table tabname add column col type q9 !)YP+w
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。 <=2\xJfxB
7、说明:添加主键: Alter table tabname add primary key(col) ~Ry?}5&:
说明:删除主键: Alter table tabname drop primary key(col) FY1
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8、说明:创建索引:create [unique] index idxname on tabname(col....) t[/WGF&(R
删除索引:drop index idxname =?hGa;/rb
注:索引是不可更改的,想更改必须删除重新建。 },<(VhP
9、说明:创建视图:create view viewname as select statement 1h_TG.YL9>
删除视图:drop view viewname MHNuA,cz
10、说明:几个简单的基本的sql语句 91'i7&~xdG
选择:select * from table1 where 范围 foO/Yc
插入:insert into table1(field1,field2) values(value1,value2) %i[G6+-
删除:delete from table1 where 范围 x{y}pH "H
更新:update table1 set field1=value1 where 范围 }Fs;sfH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *9Eep~ 6
排序:select * from table1 order by field1,field2 [desc] lr[U6CJY
总数:select count as totalcount from table1 2H+!78
求和:select sum(field1) as sumvalue from table1 _M[@a6?
平均:select avg(field1) as avgvalue from table1 !0i6:2nw
最大:select max(field1) as maxvalue from table1 t&m8 V$Q
最小:select min(field1) as minvalue from table1 } o^VEJc`O
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11、说明:几个高级查询运算词 !7)` g i
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A: UNION 运算符 I|&<!{Rq
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 pK/r{/>r
B: EXCEPT 运算符 uW4)DT9[5
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ,i0Dw"/u
C: INTERSECT 运算符 "QCtF55X&
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 E<6Fjy
注:使用运算词的几个查询结果行必须是一致的。 qaE>])
12、说明:使用外连接 jUnS&1]MF
A、left outer join: [\|`C4@3a
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 \M$e#^g
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 =zaf{0c
B:right outer join: r:rM~``
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。 ol^uM .k%_
C:full outer join: -;T!d
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。 K,B qVu
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二、提升 I$yFCd Xr
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) LTsX{z
法一:select * into b from a where 1<>1 EL/~c*a/
法二:select top 0 * into b from a ~1xfE C/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) (x)}k&B;
insert into b(a, b, c) select d,e,f from b; y^OT0mZkg
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) QlxzWd3=q
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )67pBj
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P_7QZ0k/
4、说明:子查询(表名1:a 表名2:b) OO$YwOKS
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) 8s+9PE
5、说明:显示文章、提交人和最后回复时间 >aw`kr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'c]Fhe fb
6、说明:外连接查询(表名1:a 表名2:b) "INIP?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5B:%##Ug5
7、说明:在线视图查询(表名1:a ) *yX5g,52-|
select * from (SELECT a,b,c FROM a) T where t.a > 1; !]#@:Z
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 TPE1}8p17
select * from table1 where time between time1 and time2 R_JB`HFy=
select a,b,c, from table1 where a not between 数值1 and 数值2 VK)vb.:
9、说明:in 的使用方法 R%%Uw %`
select * from table1 where a [not] in ('值1','值2','值4','值6') <vb%i0+b.^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 &7-ENg9 [
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <I
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11、说明:四表联查问题: w;
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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 ..... !!KA9mP
12、说明:日程安排提前五分钟提醒 8D]&wBR:
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ab-z 7g
13、说明:一条sql 语句搞定数据库分页 `#g62wb,HY
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 ~-J!WC==U
14、说明:前10条记录 >_3P6-L>
select top 10 * form table1 where 范围 FGRdA^`
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.) H^TU?vz}
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %2q0lFdcM
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 5u5-:#sLy
(select a from tableA ) except (select a from tableB) except (select a from tableC) =\ek;d0Tqb
17、说明:随机取出10条数据 r(qwzUI
select top 10 * from tablename order by newid() }F
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18、说明:随机选择记录 iNO}</7?
select newid() v~B
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19、说明:删除重复记录 .
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _n~[wb5J
20、说明:列出数据库里所有的表名 %tK^&rw%
select name from sysobjects where type='U' 7M.TLV!f]
21、说明:列出表里的所有的 w%2|Po5
select name from syscolumns where id=object_id('TableName') .`ZuUr
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。 @A.7`*i_
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 G~ONHXL
显示结果: 1#w'<}h#U
type vender pcs k00&+C
电脑 A 1 E[=#Rw!*
电脑 A 1 YqQAogyh
光盘 B 2 O)FkpZc@9c
光盘 A 2 7;8DKY q
手机 B 3 F!RzF7h1
手机 C 3 hJc^NU5
23、说明:初始化表table1 (ah^</
TRUNCATE TABLE table1 {SRv=g
24、说明:选择从10到15的记录 SuJa?VU1w
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc fD* ?JzVY
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三、技巧 eWk
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1、1=1,1=2的使用,在SQL语句组合时用的较多 6Zx'$F.iqK
"where 1=1" 是表示选择全部 "where 1=2"全部不选, kJ_XG;8
如: 'Szk!,_
if @strWhere !='' FgnS+c3W(
begin F2^qf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere (~Hwq:=.
end uS|f|)U&
else b/]@G05>>
begin 1nZ7xCDK98
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 4qKMnYR
end Ly~s84k_po
我们可以直接写成 cT.8&EEW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )e?6 Ncy
2、收缩数据库 6j6P&[
--重建索引 @xkI?vK6
DBCC REINDEX m\"X%Y#
DBCC INDEXDEFRAG na`8ulN_
--收缩数据和日志 4_KRH1
DBCC SHRINKDB FdE9k\E#/)
DBCC SHRINKFILE d%lwg~@&|5
3、压缩数据库 6DxT(VU}
dbcc shrinkdatabase(dbname) pKzrdw-!
4、转移数据库给新用户以已存在用户权限 /4Sul*{hc
exec sp_change_users_login 'update_one','newname','oldname' 08W^
go w:|YOeP
5、检查备份集 b/g~;| <
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &eIwlynm
6、修复数据库 )J(@e4;Rv
ALTER DATABASE [dvbbs] SET SINGLE_USER Y![//tg
GO $.Qu55=z<
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 3;er.SFu{
GO a
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ALTER DATABASE [dvbbs] SET MULTI_USER btDPP k'
GO q+1SU6x'm
7、日志清除 52v@zDY
SET NOCOUNT ON A5 <T7~U
DECLARE @LogicalFileName sysname, rXF=/
@MaxMinutes INT, |QO)xEn~
@NewSize INT r34 GO1d
USE tablename -- 要操作的数据库名 '(fCi
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 FV>xAU$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. IWNIk9T,u
@NewSize = 1 -- 你想设定的日志文件的大小(M) 'Im&&uSkr
-- Setup / initialize Epm%/ {sHV
DECLARE @OriginalSize int @D2KDV3'
SELECT @OriginalSize = size PESJ7/^E
FROM sysfiles Y}hz UKJ
WHERE name = @LogicalFileName hB1Gtc4n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^!x}e+ o
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + c]3^2Ag,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rCn"{.rI
FROM sysfiles Y6ORI
WHERE name = @LogicalFileName M^?=!!US^
CREATE TABLE DummyTrans qy,X#y'FuE
(DummyColumn char (8000) not null) VK/i5yT5N
DECLARE @Counter INT, Y^ti;:
@StartTime DATETIME, Jh`6@d
@TruncLog VARCHAR(255) W}.p, d
SELECT @StartTime = GETDATE(), F9 4Qb}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' E|BiK
DBCC SHRINKFILE (@LogicalFileName, @NewSize) eSA%:Is.
EXEC (@TruncLog) #e5*Dr8
-- Wrap the log if necessary. -) \!@n0
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) a^MR"i>@G
AND (@OriginalSize * 8 /1024) > @NewSize gt:Ot0\7
BEGIN -- Outer loop. ~\~XD+jy"
SELECT @Counter = 0 *h Bo,
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) pNzpT!}H>
BEGIN -- update 5:x .<
INSERT DummyTrans VALUES ('Fill Log') [.*o<
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DELETE DummyTrans P(XNtQ= K
SELECT @Counter = @Counter + 1 qkh.?~
END !|;w(/
EXEC (@TruncLog) M$AQZ')9
END i'NN
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :rX/ILAr
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + n$YCIW)0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @V5'+^O
FROM sysfiles G[[NDK
WHERE name = @LogicalFileName ^bckl
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DROP TABLE DummyTrans pgU4>tyD
SET NOCOUNT OFF 9KLhAYaq
8、说明:更改某个表 lL6qK&;
exec sp_changeobjectowner 'tablename','dbo' J"O#w BM9
9、存储更改全部表 j,CMcP7A -
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch m[!AOln)
@OldOwner as NVARCHAR(128), >6cENe_@t
@NewOwner as NVARCHAR(128) :fE*fU@
AS `<kV)d%xEF
DECLARE @Name as NVARCHAR(128) "K*+8IO2
DECLARE @Owner as NVARCHAR(128) WX9pJ9d
DECLARE @OwnerName as NVARCHAR(128) +gsk}>"
DECLARE curObject CURSOR FOR DU:
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select 'Name' = name, S&m5]h!D
'Owner' = user_name(uid) y$7@ ~NH,d
from sysobjects rXR}]|;>
where user_name(uid)=@OldOwner vy+9Q5@W
order by name j])nkm7_
OPEN curObject ^iwM(d]#5
FETCH NEXT FROM curObject INTO @Name, @Owner Y2Y!^A89
WHILE(@@FETCH_STATUS=0) V7
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BEGIN -hP-w>
if @Owner=@OldOwner #pz{,
begin ofA6EmQ37
set @OwnerName = @OldOwner + '.' + rtrim(@Name) v__;oqN0
exec sp_changeobjectowner @OwnerName, @NewOwner dj0`Q:VZ
end *cn#W]AE
-- select @name,@NewOwner,@OldOwner v^_<K4N`
FETCH NEXT FROM curObject INTO @Name, @Owner tHo0q<.oX
END 5`3f"(ay/
close curObject %1p4K)
deallocate curObject |uE_aFQs
GO Pf]O'G&F
10、SQL SERVER中直接循环写入数据 I NE,/a=
declare @i int ~IE5j,SC
set @i=1 ,w/f:-y
while @i<30 'd@Vusq}2
begin
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insert into test (userid) values(@i) 7F{=bL
set @i=@i+1 WsCzC_'j.
end ^2PQ75V@.
小记存储过程中经常用到的本周,本月,本年函数 +6*
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Dateadd(wk,datediff(wk,0,getdate()),-1) AH(O"v`
Dateadd(wk,datediff(wk,0,getdate()),6) N#`aVW'{v2
Dateadd(mm,datediff(mm,0,getdate()),0) .iL_3:6f
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) K!9rH>`\
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) y'k4>,`9e
上面的SQL代码只是一个时间段 9/k?Lv
Dateadd(wk,datediff(wk,0,getdate()),-1) TIa`cU`
Dateadd(wk,datediff(wk,0,getdate()),6) (u
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就是表示本周时间段. kty,hAXe
下面的SQL的条件部分,就是查询时间段在本周范围内的: = *A_{u;E
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rHtT>UE=
而在存储过程中 " lf_`4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]41G!'E=
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) uhLg2G^h