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。 6SBvn%
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一、基础 M?~<w)L}
1、说明:创建数据库 `KJYm|@ i
CREATE DATABASE database-name }#W`<,*rL.
2、说明:删除数据库 v;bP8)mI
drop database dbname 3ES[ N.V#
3、说明:备份sql server `\F%l?aY
--- 创建 备份数据的 device Cs[7% j
USE master g
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' <.=#EV^i
--- 开始 备份 QTjftcu
BACKUP DATABASE pubs TO testBack <V:<x
4、说明:创建新表 x\J;ZiWwW
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 4$zFR}f
根据已有的表创建新表: ZkB6bji
A:create table tab_new like tab_old (使用旧表创建新表) |;.Pj3)-
B:create table tab_new as select col1,col2... from tab_old definition only q
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5、说明:删除新表 *)`kx
drop table tabname :m++ iR
6、说明:增加一个列 !(]dz~sM
Alter table tabname add column col type g#'fd/?Q
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 |j~EV~AJ
7、说明:添加主键: Alter table tabname add primary key(col) UrhM)h?%
说明:删除主键: Alter table tabname drop primary key(col) Z'}(t,
8、说明:创建索引:create [unique] index idxname on tabname(col....) Vy%
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删除索引:drop index idxname wsJ%*
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注:索引是不可更改的,想更改必须删除重新建。 U!\2K~
9、说明:创建视图:create view viewname as select statement Dz8:;$/
删除视图:drop view viewname [UJEU~XC
10、说明:几个简单的基本的sql语句 WE.$a t{*h
选择:select * from table1 where 范围 y KYP
插入:insert into table1(field1,field2) values(value1,value2) $vTAF-~Ql
删除:delete from table1 where 范围 $\,BpZ
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更新:update table1 set field1=value1 where 范围 W`Q$t56
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Hw?2XDv j
排序:select * from table1 order by field1,field2 [desc] ,u&tB|,W,
总数:select count as totalcount from table1 ;naq-%'Sg
求和:select sum(field1) as sumvalue from table1 NlF0\+h
平均:select avg(field1) as avgvalue from table1 M<Wn]}7!
最大:select max(field1) as maxvalue from table1 .@i0U
最小:select min(field1) as minvalue from table1 ]~prR?
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11、说明:几个高级查询运算词 =CjNtD2]
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A: UNION 运算符 J+71FP`ZH
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。 &SjHrOG?
B: EXCEPT 运算符 97(Xu=tX
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。 S$jV|xKB
C: INTERSECT 运算符 <}EV*`w4
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。 tM^;?HL]
注:使用运算词的几个查询结果行必须是一致的。 *gd?>P7\0
12、说明:使用外连接 2JiAd*WK
A、left outer join: !EX?m }7
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。 QY~<~<d+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 U/X|i /
B:right outer join: ~_u*\]-
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。 15xd~V?ai:
C:full outer join: g5tjj.
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。 Q e>i{:N
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二、提升 af<NMgT2s~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) IpWy)B>Fl3
法一:select * into b from a where 1<>1 $hjP}- oUX
法二:select top 0 * into b from a M&qh]v gC
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 'dIX=/RZ
insert into b(a, b, c) select d,e,f from b; v[{8G^Z}54
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Fl_dzh,E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 G$;]
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. M5GY>3P$c
4、说明:子查询(表名1:a 表名2:b) f0uUbJ5
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) eVw\v#gd
5、说明:显示文章、提交人和最后回复时间 jl.okWuiY
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ]#Vo}CVP
6、说明:外连接查询(表名1:a 表名2:b) +Lm3vj_N
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c j+DE|Q&]I
7、说明:在线视图查询(表名1:a ) 1B)Y;hg6&
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7P<r`,~k-
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 w]>"'o{{
select * from table1 where time between time1 and time2 &1z)fD2
select a,b,c, from table1 where a not between 数值1 and 数值2 oA4D\rn8"
9、说明:in 的使用方法 `Yx-~y5X
select * from table1 where a [not] in ('值1','值2','值4','值6') 0'?V|V=v
10、说明:两张关联表,删除主表中已经在副表中没有的信息 vKNt$]pm=
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) q2x|%HRF
11、说明:四表联查问题: .FIt.XPzv
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 ..... omM&{ }8 g
12、说明:日程安排提前五分钟提醒 ~ X-)_zH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 p?+lAbe6H
13、说明:一条sql 语句搞定数据库分页 Sa3I?+
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 B{7Kzwh;
14、说明:前10条记录 1. #
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select top 10 * form table1 where 范围 "?apgx 6
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.) j5L)N
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) KX?o
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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 T-4/d5D[
(select a from tableA ) except (select a from tableB) except (select a from tableC) xGYSi5}z
17、说明:随机取出10条数据 EY+/.=$x
select top 10 * from tablename order by newid() XR*Q|4
18、说明:随机选择记录 QS3U)ZO$@
select newid() ]43al f F#
19、说明:删除重复记录 uYFMv=>j
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %1Bn_
20、说明:列出数据库里所有的表名 [Q4_WKI0T
select name from sysobjects where type='U' wYZT D*A2h
21、说明:列出表里的所有的 C=fsJ=a5;
select name from syscolumns where id=object_id('TableName') Z?m
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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。 ipG5l
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 x|]\1sb"
显示结果: iM:yX=>a
type vender pcs \Sg<='/{L;
电脑 A 1 q=|R89
电脑 A 1 H@V 7!d
光盘 B 2 s K+
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光盘 A 2 *_`76`cz%X
手机 B 3 IQ ){(Y
手机 C 3 nD7|8,'
23、说明:初始化表table1 NF6X- ,cd
TRUNCATE TABLE table1 yJ%t^ X_
24、说明:选择从10到15的记录 <&4nOt
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 9|'
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三、技巧 G+0><,S
1、1=1,1=2的使用,在SQL语句组合时用的较多 9]"S:{KSCn
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ac9qj
如: v @:~mwy
if @strWhere !='' kr%2 w
begin XC=%H'p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Y[2Wt%2\6
end &e5(Djz8t
else (=1)y'.
begin U4Z[!s$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' MWiMUTZg3
end 2@vJ
我们可以直接写成 n5|l|#c$N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere COR;e`%,
2、收缩数据库 Jlp<koy
--重建索引 mw_ E&v
DBCC REINDEX VZ$=6CavH
DBCC INDEXDEFRAG ^$!987"
--收缩数据和日志 W4(v6>5l
DBCC SHRINKDB sONBQ9
DBCC SHRINKFILE o/C(4q6d
3、压缩数据库 g& k58{e
dbcc shrinkdatabase(dbname) $[g_=Z
4、转移数据库给新用户以已存在用户权限 !=3Rg-'d1
exec sp_change_users_login 'update_one','newname','oldname' Guh%eR'Wt
go rz6uDJ"
5、检查备份集 :p' VbQZ{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qz 9tr
6、修复数据库 ~3gru>qI&
ALTER DATABASE [dvbbs] SET SINGLE_USER Y$g}XN*)E
GO `-_N@E1'>
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !YiuwFt
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER ` @8`qXg
GO 'n0 .#E_
7、日志清除 -T7xK/
SET NOCOUNT ON v!H:^!z
DECLARE @LogicalFileName sysname, 7{f_fkbs
@MaxMinutes INT, [*)Z!)
@NewSize INT ZPHXzi3j
USE tablename -- 要操作的数据库名 {XgnZ`*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5o#Yt
@MaxMinutes = 10, -- Limit on time allowed to wrap log. FW8-'~
@NewSize = 1 -- 你想设定的日志文件的大小(M) rz%<AF Z
-- Setup / initialize Jic}+X*0
DECLARE @OriginalSize int ?vgH"W~3>
SELECT @OriginalSize = size NBjeHtT
FROM sysfiles 6 "U8V?E
WHERE name = @LogicalFileName -I":Z2.fR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + C9qJP^F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4,G w#@
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' |ETiLR=&
FROM sysfiles ][d,l\gu+s
WHERE name = @LogicalFileName 'xnnLCm.
CREATE TABLE DummyTrans X<]qU3k5
(DummyColumn char (8000) not null) XX6 T$pA6
DECLARE @Counter INT, fTqC:r|st
@StartTime DATETIME, o%[U
@TruncLog VARCHAR(255) Z)pz,
SELECT @StartTime = GETDATE(), 2Vk\L~K
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' F2 ~%zNe
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g%xGOA
EXEC (@TruncLog) 1f#mHt:(
-- Wrap the log if necessary. fr[3:2g-_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired r[_4Lo@G
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) R^*K6Ad
AND (@OriginalSize * 8 /1024) > @NewSize dRI^@n
BEGIN -- Outer loop. -h#mn2U~3r
SELECT @Counter = 0 zP!J/}z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) >O7~h[FN
BEGIN -- update kS :\Oz\
INSERT DummyTrans VALUES ('Fill Log') JN'cXZJPn
DELETE DummyTrans G^wtE90
SELECT @Counter = @Counter + 1 w~Ff%p@9
END 5Y\!pf7SQ|
EXEC (@TruncLog) V-!"%fO.s
END Kmz7c|
SELECT 'Final Size of ' + db_name() + ' LOG is ' + DNkWOY#{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + uS+k^
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J:j<"uPm
FROM sysfiles F7MzCZvu
WHERE name = @LogicalFileName PUdM[-zjh
DROP TABLE DummyTrans M2@b1;
SET NOCOUNT OFF -x`G2i
8、说明:更改某个表 M+`Hg_#Q
exec sp_changeobjectowner 'tablename','dbo' R}:KE&tq
9、存储更改全部表 !}KqB8;
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )US:.7A[.
@OldOwner as NVARCHAR(128), [zkikZy
@NewOwner as NVARCHAR(128) o.-C|IXG
AS |J0Q,F]T
DECLARE @Name as NVARCHAR(128) '
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DECLARE @Owner as NVARCHAR(128) G{9X)|d
DECLARE @OwnerName as NVARCHAR(128) l4y{m#/
DECLARE curObject CURSOR FOR gRJfX%*F
select 'Name' = name, |o<8}Nja6
'Owner' = user_name(uid) tMp=-"
from sysobjects %Sk@GNI_
where user_name(uid)=@OldOwner v4Ga0]VN$8
order by name 7^*"O&y_al
OPEN curObject awewYf$li
FETCH NEXT FROM curObject INTO @Name, @Owner /`npQg-
WHILE(@@FETCH_STATUS=0) 8|Y.|\
BEGIN "YU{Fkl#j
if @Owner=@OldOwner |=a}iU8
begin &o3K%M;C?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) BxK^?b[E8
exec sp_changeobjectowner @OwnerName, @NewOwner lb*8G
end ww k
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-- select @name,@NewOwner,@OldOwner _-~`03 `!
FETCH NEXT FROM curObject INTO @Name, @Owner Zm
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END BV`- =wRC
close curObject wJ<Oo@snm
deallocate curObject h*B|fy4K9U
GO !ZRs;UZ>o
10、SQL SERVER中直接循环写入数据 sZ<9A Xk-E
declare @i int CjIu[S1%
set @i=1 ]rN5Ao}2
while @i<30 .lgPFr6X
begin *i{Y 9f8
insert into test (userid) values(@i) f.B>&%JRZ
set @i=@i+1 6
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end A"5z6A4WB
小记存储过程中经常用到的本周,本月,本年函数 US [dkbKo
Dateadd(wk,datediff(wk,0,getdate()),-1) 4*.K'(S5fx
Dateadd(wk,datediff(wk,0,getdate()),6) 3jH \yXj
Dateadd(mm,datediff(mm,0,getdate()),0) k
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;a{ :%t
Dateadd(yy,datediff(yy,0,getdate()),0) NS)}6OI3~"
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) X[gn+6WB%
上面的SQL代码只是一个时间段 &k7;DO
Dateadd(wk,datediff(wk,0,getdate()),-1) 4)>FS'=
Dateadd(wk,datediff(wk,0,getdate()),6) ._9
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就是表示本周时间段. R9rj/Co
下面的SQL的条件部分,就是查询时间段在本周范围内的: jjM\. KL]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) OS|> t./U
而在存储过程中 YXurYwV
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E m
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) bI)u/