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。 Q`5jEtu#,
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一、基础
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1、说明:创建数据库 .X_k[l 9
CREATE DATABASE database-name 7<IrN\@U
2、说明:删除数据库 bxkp9o
drop database dbname FxM`$n~K
3、说明:备份sql server HY5g>wv@
--- 创建 备份数据的 device [Gh T.
USE master MyCX6+Ci)
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~;UK/OZ
--- 开始 备份 )uwpeq$j7l
BACKUP DATABASE pubs TO testBack {*
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4、说明:创建新表 ^CZn<$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;?= ] ffa{
根据已有的表创建新表: \ts:'
A:create table tab_new like tab_old (使用旧表创建新表) Va(R*38k
B:create table tab_new as select col1,col2... from tab_old definition only B*Hp
5、说明:删除新表 k/?+jb
drop table tabname %
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6、说明:增加一个列 N(t1?R/e,
Alter table tabname add column col type swi|
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。 ;o%r{:lng
7、说明:添加主键: Alter table tabname add primary key(col) 0RtqqNFD
说明:删除主键: Alter table tabname drop primary key(col) l=
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8、说明:创建索引:create [unique] index idxname on tabname(col....) >W.Pg`'D
删除索引:drop index idxname "E/F{6NH
注:索引是不可更改的,想更改必须删除重新建。 wF?THkdFo
9、说明:创建视图:create view viewname as select statement 0@*rp7
删除视图:drop view viewname 72~)bu
10、说明:几个简单的基本的sql语句 4xtbP\=
选择:select * from table1 where 范围 }k \a~<'X
插入:insert into table1(field1,field2) values(value1,value2) z}8rD}BH
删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 #jA|04w
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \w^U<_zq
排序:select * from table1 order by field1,field2 [desc] qa`bR%eH
总数:select count as totalcount from table1 NZ7a^xT_)
求和:select sum(field1) as sumvalue from table1 Iimz
平均:select avg(field1) as avgvalue from table1 f*W<N06EZ
最大:select max(field1) as maxvalue from table1 l:j9lBS
最小:select min(field1) as minvalue from table1 D'Byl,W$
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11、说明:几个高级查询运算词 +P}'2tE~'
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A: UNION 运算符 ,6i67!lb
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。 .s7o$u~l
B: EXCEPT 运算符 #(ANyU(#e
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =ZzhH};aX
C: INTERSECT 运算符 r A0[ y
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 <X|"5/h
注:使用运算词的几个查询结果行必须是一致的。 2x$\vL0
12、说明:使用外连接 (tyo4Tz1
A、left outer join: y'2K7\>E
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。 xx!o]D-}
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 lNqXx{!k
B:right outer join: aJI>qk h?]
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。 Yfxc$ub
C:full outer join: #3kR}Amow
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 2}~1poyi>
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二、提升 ,o*b-Cv/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [A*vl9=
法一:select * into b from a where 1<>1 Gxm+5q
法二:select top 0 * into b from a 8{%/!ylJz
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) N7+K$)3
insert into b(a, b, c) select d,e,f from b; 0)k%nIhj
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) mQVduG
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 1m}'Y@I
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. rZ:
4、说明:子查询(表名1:a 表名2:b) &rcr])jg[
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
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5、说明:显示文章、提交人和最后回复时间 UO<uG#FB
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0<!kGL5
6、说明:外连接查询(表名1:a 表名2:b) 99:`58G
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -uy}]s5Qu
7、说明:在线视图查询(表名1:a ) yq6!8OkF
select * from (SELECT a,b,c FROM a) T where t.a > 1; F[RhuNa&'W
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 lSXhHy
select * from table1 where time between time1 and time2 }! zjj\g^
select a,b,c, from table1 where a not between 数值1 and 数值2 W!XFaA$
9、说明:in 的使用方法 a^4(7
select * from table1 where a [not] in ('值1','值2','值4','值6')
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 z7HC6{g%X
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) hl6al:Y
11、说明:四表联查问题: C:EF(/>+-
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 ..... I?bL4u$\
12、说明:日程安排提前五分钟提醒 %b@>riR(y
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e!eWwC9u
13、说明:一条sql 语句搞定数据库分页 rLh490@
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 ,_\h)R_
14、说明:前10条记录 "pMXTRb
select top 10 * form table1 where 范围 la|#SS95
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.) =E4nNL?
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3,N7Nfe
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 >tib21*
(select a from tableA ) except (select a from tableB) except (select a from tableC) wT*`Od8w
17、说明:随机取出10条数据 iLv"ZqGrw
select top 10 * from tablename order by newid() ^4 es
18、说明:随机选择记录 05|t
select newid() pA+Qb.z5z
19、说明:删除重复记录 ^]E| >~\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) /*rMveT
20、说明:列出数据库里所有的表名 oDKgW?x
select name from sysobjects where type='U' Pbm;@V
21、说明:列出表里的所有的 Wd~}O<"
select name from syscolumns where id=object_id('TableName') 7@+0E2'
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。 s_D7?o
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 K8284A8v
显示结果: FY#`]124*
type vender pcs 1D=My1B
电脑 A 1 I0Wn?Qq=@
电脑 A 1 Haq23K
光盘 B 2 zx=A3I%7 A
光盘 A 2 1REq.%/=
手机 B 3 >6jyd{
手机 C 3 R`TM@aaS:
23、说明:初始化表table1 _@?]!J[
TRUNCATE TABLE table1 ag|d_;
24、说明:选择从10到15的记录 ~@itZ,d\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {) Y
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三、技巧 @H7dQ,%
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, !X[lNtO
如: IO v4Zx<)
if @strWhere !='' p)TH^87
begin Lc<Gny^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mUnnk`v
end , aawtdt/
else Ix1ec^?f
begin pC#Z]_k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' LNg[fF^:
end 3b%y+?-{\u
我们可以直接写成 W=F?+KgL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [0)iY%^
2、收缩数据库 i}+dctg/
--重建索引 >OiC].1
DBCC REINDEX :Tj,;0#/
DBCC INDEXDEFRAG Hej0l^
--收缩数据和日志 VMen:
DBCC SHRINKDB +k8><_vr}
DBCC SHRINKFILE ~j F5%Gu
3、压缩数据库 DrMcE31
dbcc shrinkdatabase(dbname) w
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4、转移数据库给新用户以已存在用户权限 [DjdR_9*I
exec sp_change_users_login 'update_one','newname','oldname' }o)GBWqHR
go (qohb0
5、检查备份集 ,:=E+sS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "#[Y[t\Ia
6、修复数据库 =_
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ALTER DATABASE [dvbbs] SET SINGLE_USER 5%tIAbGW
GO nwO;>Qr
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK KwpNS(]I
GO 7sHtJr
ALTER DATABASE [dvbbs] SET MULTI_USER {wA@5+[
GO ;'=!Fv
7、日志清除 K})j5CJ/
SET NOCOUNT ON QKCk. 0Xe
DECLARE @LogicalFileName sysname, Vfc9+T+
@MaxMinutes INT, dzbzZ@y
@NewSize INT CHBCi) '6h
USE tablename -- 要操作的数据库名 b%|%Rek8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 8V~w3ssz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d/R:-{J)c
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9RR1$( f
-- Setup / initialize ~^Vt)/}Q
DECLARE @OriginalSize int rl4daV&,U
SELECT @OriginalSize = size kw=+"U
FROM sysfiles vQBfT% &Q-
WHERE name = @LogicalFileName W dIr3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p1X
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Ev$?c9*>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \Sm.]=br
FROM sysfiles [lyB@) 6.
WHERE name = @LogicalFileName <V>vDno\
CREATE TABLE DummyTrans n:k~\-&WJ
(DummyColumn char (8000) not null) [!bTko>rSB
DECLARE @Counter INT, <niHJ*
@StartTime DATETIME, 3~Ipcr
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@TruncLog VARCHAR(255) %li'j|
SELECT @StartTime = GETDATE(), <([o4%
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7/aJ?:gX
DBCC SHRINKFILE (@LogicalFileName, @NewSize) q;B-np?U
EXEC (@TruncLog) '1.T-.4>&
-- Wrap the log if necessary. TS=p8@w}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6Y}#vZ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _Vp9Y:mX2
AND (@OriginalSize * 8 /1024) > @NewSize LZ\}Kgi(!T
BEGIN -- Outer loop. qx`*]lX
SELECT @Counter = 0 :Q&8DC#]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) J0|/g2%0
BEGIN -- update eeB^c/k(P
INSERT DummyTrans VALUES ('Fill Log') .&}}ro48
DELETE DummyTrans ,h> 0k`J:a
SELECT @Counter = @Counter + 1 Kr]F+erJe
END LvW9kL+WiQ
EXEC (@TruncLog) $C^94$W
END S=M$g#X`5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &x;v&
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + "v^Q
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 8 kd
FROM sysfiles Pf@8C{I
WHERE name = @LogicalFileName k[G? 22t
DROP TABLE DummyTrans s "*Cb*
SET NOCOUNT OFF $?;aW^E
8、说明:更改某个表 OZk(VMuI
exec sp_changeobjectowner 'tablename','dbo' lBPZB%
9、存储更改全部表 t0}3QGf;c
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 5QMu=/
@OldOwner as NVARCHAR(128), dwAju:-H
@NewOwner as NVARCHAR(128) H;IG\k6C
AS 4b6$Mj
DECLARE @Name as NVARCHAR(128) z@<`]
DECLARE @Owner as NVARCHAR(128) 0v',+-
DECLARE @OwnerName as NVARCHAR(128) &XgB-}^:
DECLARE curObject CURSOR FOR F=d#$-yg
select 'Name' = name, Ng+k{vAj
'Owner' = user_name(uid) dwJ'hg
from sysobjects Q[8L='E
where user_name(uid)=@OldOwner roL~r`f`
order by name M}M.
OPEN curObject ZJ+q<n_4}
FETCH NEXT FROM curObject INTO @Name, @Owner \zgRzO'N
WHILE(@@FETCH_STATUS=0) D97oS!*
BEGIN SDdK5@1O4o
if @Owner=@OldOwner bl}$x/
begin f]o DZO%^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9e8@0?0
exec sp_changeobjectowner @OwnerName, @NewOwner oa;[[2c
end =_L"x~0I-
-- select @name,@NewOwner,@OldOwner 1Qf5H!5vx
FETCH NEXT FROM curObject INTO @Name, @Owner $WTu7lVV[1
END #2x\d
close curObject ("H:T?4Qs
deallocate curObject BflF*-s ^
GO P1z6sGG
10、SQL SERVER中直接循环写入数据 !|Vjv}UO
declare @i int OL=IUg"
set @i=1 _|H]X+|
while @i<30 "kf7??Z
begin :
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insert into test (userid) values(@i) AO/J:`
set @i=@i+1 i3#]_ p{
end yUNl)E
小记存储过程中经常用到的本周,本月,本年函数 }54\NSj0
Dateadd(wk,datediff(wk,0,getdate()),-1) Ct
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Dateadd(wk,datediff(wk,0,getdate()),6) #T
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Dateadd(mm,datediff(mm,0,getdate()),0) %&e5i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /Q{Jf+>R>
Dateadd(yy,datediff(yy,0,getdate()),0) Vs9fAAXS4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Wq"pKI#x
上面的SQL代码只是一个时间段 ap_(/W
Dateadd(wk,datediff(wk,0,getdate()),-1) q(a6@6f"kD
Dateadd(wk,datediff(wk,0,getdate()),6) ^@L
就是表示本周时间段. y"2#bq
下面的SQL的条件部分,就是查询时间段在本周范围内的: 9$#2+G!J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7xWX:2l*?
而在存储过程中 #4~Ivj
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) bumS>:
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) !m]76=@