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。 KPF1cJ2N
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一、基础 C _Dn{
1、说明:创建数据库 U/U);frH
CREATE DATABASE database-name K-4PI+qQ\
2、说明:删除数据库 CZ;6@{ o
drop database dbname UNYqft4
3、说明:备份sql server Da|z"I
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--- 创建 备份数据的 device \hXDO_U
USE master A"]YM'.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' p{_" bB
--- 开始 备份 Y4-t7UlS;
BACKUP DATABASE pubs TO testBack Ac@VGT:9
4、说明:创建新表 ,bi^P>X
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) It(_v
根据已有的表创建新表: DQ3<$0
A:create table tab_new like tab_old (使用旧表创建新表) F5<Hm_\:
B:create table tab_new as select col1,col2... from tab_old definition only By|4m
5、说明:删除新表 2G7Wi!J
drop table tabname 'L'R9&o<X
6、说明:增加一个列 dd;~K&_Q/i
Alter table tabname add column col type \e*]Ls#jS
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。 $FV NCFN%
7、说明:添加主键: Alter table tabname add primary key(col) e
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说明:删除主键: Alter table tabname drop primary key(col) T)/eeZ$
8、说明:创建索引:create [unique] index idxname on tabname(col....) .#gzP2 [q
删除索引:drop index idxname M3\AY30L
注:索引是不可更改的,想更改必须删除重新建。 oR'm2d ^
9、说明:创建视图:create view viewname as select statement Cdn J&N{
删除视图:drop view viewname 0mE 0 j
10、说明:几个简单的基本的sql语句 [0!( xp^
选择:select * from table1 where 范围 SUiOJ[5,
插入:insert into table1(field1,field2) values(value1,value2) q V=!ORuj
删除:delete from table1 where 范围 -@'FW*b
更新:update table1 set field1=value1 where 范围 @d'j zs
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! l?e.9o2-
排序:select * from table1 order by field1,field2 [desc] c 9Mz]1@f
总数:select count as totalcount from table1 (PLUFT
求和:select sum(field1) as sumvalue from table1 $Sq:q0
平均:select avg(field1) as avgvalue from table1 { 6il`>=C
最大:select max(field1) as maxvalue from table1 KlEpzJ98
最小:select min(field1) as minvalue from table1 x2xRBkRg=
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11、说明:几个高级查询运算词 "oyo#-5z
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A: UNION 运算符 e\rp)[>'
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 F9^S"qv$
B: EXCEPT 运算符 )%TmAaj9d
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。 43cE`9~
C: INTERSECT 运算符 !
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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。 W?&%x(6M
注:使用运算词的几个查询结果行必须是一致的。 k$Vl fQ'+
12、说明:使用外连接 }>\C{ClI
A、left outer join: *~`(RV
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 '/p4O2b,
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c " bG2:
B:right outer join: !WlH'y-I
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 4+n\k
C:full outer join: @ Qe0! (_=
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 7zMr:JmV
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二、提升 [g,}gyeS(
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Ri'n
法一:select * into b from a where 1<>1 )7@0[>
法二:select top 0 * into b from a qs6aB0ln
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {
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insert into b(a, b, c) select d,e,f from b; gw(z1L5
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) {g6%(X\r.r
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 2oW"'43X
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~&O%N
4、说明:子查询(表名1:a 表名2:b) ~[: 2I
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) CLSK'+l
5、说明:显示文章、提交人和最后回复时间 Efe 7gE'
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #$vEGY}1
6、说明:外连接查询(表名1:a 表名2:b) ^Cmyx3O^
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 0(Ij%Wi,
7、说明:在线视图查询(表名1:a ) i4Jc.8^9$
select * from (SELECT a,b,c FROM a) T where t.a > 1; QJNFA}*>
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 qR.Q,(b|
select * from table1 where time between time1 and time2 e!`i3KYn"
select a,b,c, from table1 where a not between 数值1 and 数值2 3$w65=
9、说明:in 的使用方法 wr4:Go`
select * from table1 where a [not] in ('值1','值2','值4','值6') c,22*.V/
10、说明:两张关联表,删除主表中已经在副表中没有的信息 =;k|*Ny
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l%ZhA=TKQ
11、说明:四表联查问题: mmsPLv6
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... <VcQ{F
12、说明:日程安排提前五分钟提醒 4 :=]<sc,
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _ |p8M!
13、说明:一条sql 语句搞定数据库分页 .pq%?&
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 f?b"i A(6
14、说明:前10条记录 ^{{ qV
select top 10 * form table1 where 范围 Q&&@v4L
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) bcR_E5x$
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 "3hMq1NQ`g
(select a from tableA ) except (select a from tableB) except (select a from tableC) P4?glh q#
17、说明:随机取出10条数据 iLz@5Zj8
select top 10 * from tablename order by newid() *H122njH+T
18、说明:随机选择记录 +RXoi2"-q@
select newid() {!`4iiF
19、说明:删除重复记录 fh{`Mz,o
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 1cGmg1U;
20、说明:列出数据库里所有的表名 7KPwQ?SjT
select name from sysobjects where type='U' m,S{p<-h
21、说明:列出表里的所有的 zJXplvaL;
select name from syscolumns where id=object_id('TableName') .-=vx r
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。 Zov~B-Of:
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 AEuG v}#
显示结果: V:27)]q
type vender pcs .l|$dE/E
电脑 A 1 b2]Kx&!
电脑 A 1 OH"XrCX7n
光盘 B 2 h$=2 p5'-
光盘 A 2 Q^I\cAIB
手机 B 3 P&q7|ST%N
手机 C 3 yBRC*0+Vy
23、说明:初始化表table1 8D].MI^
TRUNCATE TABLE table1 h1{3njdr
24、说明:选择从10到15的记录 ?}7p"3j'z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {x7,
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三、技巧 hEk$d.!}
1、1=1,1=2的使用,在SQL语句组合时用的较多 'n|5ZhXPB
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Jo}eeJ;k
如: - YV>j
if @strWhere !='' akT6^cP^
begin Fx+*S3==%e
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere kW (Bkuc)
end xKC[=E>z
else TPY}C
begin E"@wek.-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 05k0n E
end n(|^SH4$b
我们可以直接写成 L6LZC2N+2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v}x&?fU `
2、收缩数据库 LK"69Qx?5q
--重建索引 eY\yE"3
DBCC REINDEX MS]r:X6
DBCC INDEXDEFRAG r9lR|\Ax2U
--收缩数据和日志 _[y/Y\{I
DBCC SHRINKDB h}EPnC}
DBCC SHRINKFILE {GO#.P"
3、压缩数据库 j+(I"h3
dbcc shrinkdatabase(dbname) ZW}_Qs
4、转移数据库给新用户以已存在用户权限 $\! 7 {6a
exec sp_change_users_login 'update_one','newname','oldname' )/EO&F
go eIo7F m
5、检查备份集 QwJyY{O`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ``Un&-Ms
6、修复数据库 pD74+/DD
ALTER DATABASE [dvbbs] SET SINGLE_USER ,1##p77.
GO ,iq4Iw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK #u
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GO 4g7)i L^#~
ALTER DATABASE [dvbbs] SET MULTI_USER 69 o7EA
GO |a%Tp3Q~
7、日志清除 :\}(&
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SET NOCOUNT ON -R6)ROGl
DECLARE @LogicalFileName sysname, nQ L@hc
@MaxMinutes INT, (3&?w y_l
@NewSize INT u?{H}V
USE tablename -- 要操作的数据库名 Ip]KPrwp
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Pco'l#:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. TNr :pE<
@NewSize = 1 -- 你想设定的日志文件的大小(M) /^|Dbx!u
-- Setup / initialize (2
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DECLARE @OriginalSize int &l[$*<P5V
SELECT @OriginalSize = size ;]jNk'oa
FROM sysfiles /[>sf[X\I9
WHERE name = @LogicalFileName Q?/o%`N
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -FlzEZ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {$Gd2gO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' O5t[
FROM sysfiles :$9tF>
WHERE name = @LogicalFileName E`k@{*Hn&
CREATE TABLE DummyTrans 0k(a VkZ I
(DummyColumn char (8000) not null) $"&{aa
DECLARE @Counter INT, m7>JJX3=<
@StartTime DATETIME, ~**.|%Kc
@TruncLog VARCHAR(255) M+9 gL3W
SELECT @StartTime = GETDATE(), R+,u^;\
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q\527^ZM
DBCC SHRINKFILE (@LogicalFileName, @NewSize) lR6x3C
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EXEC (@TruncLog) ig':%2V/
-- Wrap the log if necessary. VgC2+APg
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1q1jZqno
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [bNx^VP*
AND (@OriginalSize * 8 /1024) > @NewSize M>8A\;"
BEGIN -- Outer loop. JO"<{ngsQ
SELECT @Counter = 0 r s?R:+
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) A:9?ZI/X
BEGIN -- update ?r+-
INSERT DummyTrans VALUES ('Fill Log') ?vHU#
DELETE DummyTrans FzXJ]H
SELECT @Counter = @Counter + 1 3%;a)c;D
END A1?2*W
EXEC (@TruncLog) x6ARzH\
END GU8sO@S5#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + {9aE5kR
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Hi`//y*92H
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3+fp2
FROM sysfiles &;sP_ h
WHERE name = @LogicalFileName U,- 39mr
DROP TABLE DummyTrans Q=20IQp
SET NOCOUNT OFF "s_lP&nq
8、说明:更改某个表 #!KE\OI;@5
exec sp_changeobjectowner 'tablename','dbo' W+X6@/BO
9、存储更改全部表 - kwXvYu\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |:<f-j7t~
@OldOwner as NVARCHAR(128), Um-[~-
@NewOwner as NVARCHAR(128) ^ tg<K
AS Jrpx}2'9:a
DECLARE @Name as NVARCHAR(128) [ )dXI IM
DECLARE @Owner as NVARCHAR(128) o,8TDg
DECLARE @OwnerName as NVARCHAR(128) H_X [t* 2
DECLARE curObject CURSOR FOR -Z
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select 'Name' = name, .KUv(-
'Owner' = user_name(uid) Z%/=|[9i
from sysobjects }YNR"X9*)/
where user_name(uid)=@OldOwner NI
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order by name hPePB=
OPEN curObject 364`IC( a
FETCH NEXT FROM curObject INTO @Name, @Owner 9g"2^^wD
WHILE(@@FETCH_STATUS=0) ssxzC4m
BEGIN y6,/:qm
if @Owner=@OldOwner scou%K
begin GV69eG3bX#
set @OwnerName = @OldOwner + '.' + rtrim(@Name) =i*;VFc
exec sp_changeobjectowner @OwnerName, @NewOwner sCk?
end XkF%.hWo
-- select @name,@NewOwner,@OldOwner c+$*$|t=v`
FETCH NEXT FROM curObject INTO @Name, @Owner C$D-Pt"+
END ?9\EN|O^
close curObject tL)t" i
deallocate curObject 2Kyl/C,
GO m?fy^>1
10、SQL SERVER中直接循环写入数据 ZR?yDgL
declare @i int
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set @i=1 ?>rW>U6:P
while @i<30 ~W+kiTsD?
begin j=aI9p
insert into test (userid) values(@i) DLMM/WJg@
set @i=@i+1 uIZ -#q
end o`P%&
小记存储过程中经常用到的本周,本月,本年函数 Y
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Dateadd(wk,datediff(wk,0,getdate()),-1) z hRB,1iG
Dateadd(wk,datediff(wk,0,getdate()),6) 8a'.ZdqC?
Dateadd(mm,datediff(mm,0,getdate()),0) ( _)jkI
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) J| bd)0
Dateadd(yy,datediff(yy,0,getdate()),0) Xudg2t)+K
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |>27B
上面的SQL代码只是一个时间段 Z}l3l`h!
Dateadd(wk,datediff(wk,0,getdate()),-1) &6YIn|}
Dateadd(wk,datediff(wk,0,getdate()),6) \uC15s<
就是表示本周时间段. u!X|A`o5i
下面的SQL的条件部分,就是查询时间段在本周范围内的: qHrA%k^!2O
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) NzSoqh{R
而在存储过程中 N<|Nwq:NN
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) lWc:$qnR-K
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) )V6Hl@v