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。 k<1i.rh
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一、基础 $]LS!@ Rm
1、说明:创建数据库 0m3hL~0(a
CREATE DATABASE database-name Zv}F?4T~:
2、说明:删除数据库 brTNwRze
drop database dbname H|aFs.S EQ
3、说明:备份sql server b"$?(Y
--- 创建 备份数据的 device -. *E<%
USE master CWeQv9h]X
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' .'=S1|_(
--- 开始 备份 Sqi9'-%m
BACKUP DATABASE pubs TO testBack 7@"X?uo%o
4、说明:创建新表 pJFn
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `!cdxKLR
根据已有的表创建新表: #;8)UNc)}
A:create table tab_new like tab_old (使用旧表创建新表) _jX,1+M
B:create table tab_new as select col1,col2... from tab_old definition only }36A eJ7L
5、说明:删除新表 K{d3)lVYCS
drop table tabname 9<3( QR
6、说明:增加一个列 Tbm
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Alter table tabname add column col type Osz=OO{
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。 #[bosb!R
7、说明:添加主键: Alter table tabname add primary key(col) fBh"
说明:删除主键: Alter table tabname drop primary key(col) v/
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8、说明:创建索引:create [unique] index idxname on tabname(col....) hwM<0Jf
删除索引:drop index idxname ~0,v Q
注:索引是不可更改的,想更改必须删除重新建。 c!HGiqp
9、说明:创建视图:create view viewname as select statement oOprzxf"+Z
删除视图:drop view viewname !y$##PZ
10、说明:几个简单的基本的sql语句 oU)(/
选择:select * from table1 where 范围 !%$[p'
插入:insert into table1(field1,field2) values(value1,value2) bYLYJ`hH<R
删除:delete from table1 where 范围 x"Ll/E)\v]
更新:update table1 set field1=value1 where 范围 N?m)u,6-l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9X*Z\-
排序:select * from table1 order by field1,field2 [desc] kL zjK]4 *
总数:select count as totalcount from table1 xp1/@Pw?
求和:select sum(field1) as sumvalue from table1 KGDN)@D
平均:select avg(field1) as avgvalue from table1 O^\:J2I(
最大:select max(field1) as maxvalue from table1 <N<0 ?GQ
最小:select min(field1) as minvalue from table1 W!HjO;
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11、说明:几个高级查询运算词 +FNGRL
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A: UNION 运算符 /
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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。 1
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B: EXCEPT 运算符 ~Q=;L>Qd
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。 97 SS0J
C: INTERSECT 运算符 5@l5exuG*m
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。 {$EX :ID
注:使用运算词的几个查询结果行必须是一致的。 s2L]H
12、说明:使用外连接 5 v.&|[\k
A、left outer join: pF6u3]
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 o;wSG81
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o.r D
B:right outer join: l'm|**
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Otu?J_ d3
C:full outer join: |};d:LwX
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 #qVvh3#g
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二、提升 #NyO'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )7Hx<?P
法一:select * into b from a where 1<>1 P4)Q5r
法二:select top 0 * into b from a gm5%X'XL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) KRGj6g+
insert into b(a, b, c) select d,e,f from b; 9.xb-m7
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) {
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;m]
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. W2h*t"5W
4、说明:子查询(表名1:a 表名2:b) 78]*Jx>L
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) a9&[Qv5-/
5、说明:显示文章、提交人和最后回复时间 \roJf&O }
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b pGU.+[|(
6、说明:外连接查询(表名1:a 表名2:b) W0x9^'=s\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c v8)wu=u
7、说明:在线视图查询(表名1:a ) Ib{#dhV
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7>im2"zm
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 %_n%-Qn
select * from table1 where time between time1 and time2 An>ai N]
select a,b,c, from table1 where a not between 数值1 and 数值2 +D
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9、说明:in 的使用方法 w)J-e gc
select * from table1 where a [not] in ('值1','值2','值4','值6') 5.-:)=
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Zl%)#=kO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) h7ZH/g$)
11、说明:四表联查问题: kReZch}
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 ..... 1d!s8um;
12、说明:日程安排提前五分钟提醒 FLJ&ZU=s
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {
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13、说明:一条sql 语句搞定数据库分页 prM)t8SE
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 \aPH_sf,
14、说明:前10条记录 A%EhRAy
select top 10 * form table1 where 范围 5G6 P p7[
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.) N/lEfy<&g:
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8=bn
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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 ({Yfsf,
(select a from tableA ) except (select a from tableB) except (select a from tableC) OS%[SHs
17、说明:随机取出10条数据 5fs,UH
select top 10 * from tablename order by newid() k2loGvBJ
18、说明:随机选择记录 Y\<w|LkD8
select newid() U5ph4G
19、说明:删除重复记录 VQf^ y q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Uth+4Aq
20、说明:列出数据库里所有的表名 $C=XSuPNK
select name from sysobjects where type='U' c{`!$Z'k<
21、说明:列出表里的所有的 ((AK7hb
select name from syscolumns where id=object_id('TableName') mGg/F&G9
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。 4D5Wse
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 ~Ih`
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显示结果: w9u|E46
type vender pcs ,c&t#mu*0
电脑 A 1 8S#&XS>o
电脑 A 1 P$Yw'3v/
光盘 B 2 V4u4{wU]
光盘 A 2 sBWyUD
手机 B 3 HQF@@
手机 C 3 oFyB-vpYQV
23、说明:初始化表table1 "Cvr("'O
TRUNCATE TABLE table1 VWd`06'BN'
24、说明:选择从10到15的记录 9T2_2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc f@9XSZ<.71
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三、技巧 }X])055S
1、1=1,1=2的使用,在SQL语句组合时用的较多 LIJ#nb
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !iHC++D
如: 'rXf
if @strWhere !='' N? S;v&q+
begin 'G[G;?F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere H{_D#It
end 5`}za-
else O)R}|
begin Y]~-S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
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end +p _?ekV\
我们可以直接写成 lZkJ<*z#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?t}s3P!Q3w
2、收缩数据库 ])v61B
--重建索引 IrRe6nf@K
DBCC REINDEX F`F|.TX
DBCC INDEXDEFRAG Y1AZ%{^0a
--收缩数据和日志 7uUq+dp
DBCC SHRINKDB AW_ YlS
DBCC SHRINKFILE i,;a( Sy4
3、压缩数据库 SG~HzQ\%
dbcc shrinkdatabase(dbname) TXd6o=
4、转移数据库给新用户以已存在用户权限 V_^pPBa
exec sp_change_users_login 'update_one','newname','oldname' [T'[7Z
go c#?~1@=
5、检查备份集 1H%p|'FKA
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %H_-`A`
6、修复数据库 qfAnMBM1@
ALTER DATABASE [dvbbs] SET SINGLE_USER O,+9r_Gh
GO o3GZcH?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Nv0a]Am
GO 4a!%eBhX"K
ALTER DATABASE [dvbbs] SET MULTI_USER SH"<f_
GO um<$L
7、日志清除 r.u\qPT&
SET NOCOUNT ON 2u0B=0x
DECLARE @LogicalFileName sysname, ETX>wZ
@MaxMinutes INT, AL&<SxuP
@NewSize INT vG)B}`M
USE tablename -- 要操作的数据库名 04-@c
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 jpXbFWgN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9!r0uU"
@NewSize = 1 -- 你想设定的日志文件的大小(M) f;+.j/ +
-- Setup / initialize ]4')H;'y
DECLARE @OriginalSize int @az<D7j2
SELECT @OriginalSize = size $6ucz'
FROM sysfiles oFt_ yU-
WHERE name = @LogicalFileName h1B_*L
SELECT 'Original Size of ' + db_name() + ' LOG is ' + xe.f]a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1NTx?JJfW
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [(3 %$?[
FROM sysfiles 03 iy[~Y2
WHERE name = @LogicalFileName PktnjdFV
CREATE TABLE DummyTrans ~ e<,GUx(]
(DummyColumn char (8000) not null) V3|"
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DECLARE @Counter INT, 5&A' +]
@StartTime DATETIME, yI!W658$6
@TruncLog VARCHAR(255) xIb{*)BUwc
SELECT @StartTime = GETDATE(), xVI"sBUu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?#doH,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) cJSwA&
EXEC (@TruncLog) .R4,fCN
-- Wrap the log if necessary. TR
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Zu~t )W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 4v(?]]X
AND (@OriginalSize * 8 /1024) > @NewSize a~!7A
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BEGIN -- Outer loop. Mu.oqT
SELECT @Counter = 0 9)[)07
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) .W9
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BEGIN -- update C=K{;.
INSERT DummyTrans VALUES ('Fill Log') 1n*"C!q
DELETE DummyTrans bz,"TG[
SELECT @Counter = @Counter + 1 *ni0.
END " :[;}f;
EXEC (@TruncLog) ,s}7KE
END 1j}e2H
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8MU7|9 Q
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + BHkicb ?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' RZ9_*Lq7+
FROM sysfiles YXF^4||j.c
WHERE name = @LogicalFileName >$3 =yw%
DROP TABLE DummyTrans uVX,[%*P
SET NOCOUNT OFF _S*QIbO
8、说明:更改某个表 hr&UD| E=
exec sp_changeobjectowner 'tablename','dbo' "cOBEhn%l
9、存储更改全部表 6%o@!|=I
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch uzp\<\d-t
@OldOwner as NVARCHAR(128), g<w1d{Td
@NewOwner as NVARCHAR(128) d;3f80Kd*
AS ^"uD:f)
DECLARE @Name as NVARCHAR(128) n"~K",~P
DECLARE @Owner as NVARCHAR(128) iHdX
DECLARE @OwnerName as NVARCHAR(128) <P*7u\9&
DECLARE curObject CURSOR FOR :2b*E`+
select 'Name' = name, <I?f=[
'Owner' = user_name(uid) =8]Ru(#Ig
from sysobjects ne[H `7c
where user_name(uid)=@OldOwner }\A0g}
order by name uc=u4@.>
OPEN curObject p lzwk>b_
FETCH NEXT FROM curObject INTO @Name, @Owner Hg\H>Z
WHILE(@@FETCH_STATUS=0) )wEXCXr!
BEGIN dry%aT
if @Owner=@OldOwner v9gaRqi8
begin f7%g=0.F
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^Y8G}Z|
exec sp_changeobjectowner @OwnerName, @NewOwner )"00fZL
end y#O/Xw
-- select @name,@NewOwner,@OldOwner r$LU$F
FETCH NEXT FROM curObject INTO @Name, @Owner Fvnf;']q
END |^w&dj\,
close curObject `"xzC $
deallocate curObject '1G0YfG}n
GO hig t(u
10、SQL SERVER中直接循环写入数据 Mu$q) u
declare @i int IpKI6[2{`f
set @i=1 p@?(m/m$
while @i<30 5a&gdqg]
begin # M
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insert into test (userid) values(@i) kc@\AZb
set @i=@i+1 <rU+{&FKNL
end X&i" K'mV
小记存储过程中经常用到的本周,本月,本年函数 N B8Yn\{B
Dateadd(wk,datediff(wk,0,getdate()),-1) u)D!Rh V&
Dateadd(wk,datediff(wk,0,getdate()),6) 7i=ER*F~
Dateadd(mm,datediff(mm,0,getdate()),0) 'Rv.6>xqc
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) B\dhw@hM
Dateadd(yy,datediff(yy,0,getdate()),0) ?.MlP,/K
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) (tg+C\
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上面的SQL代码只是一个时间段 Wx8cK=
Dateadd(wk,datediff(wk,0,getdate()),-1) LH~
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Dateadd(wk,datediff(wk,0,getdate()),6) iZ(p]0aP7
就是表示本周时间段. u^L_X A
下面的SQL的条件部分,就是查询时间段在本周范围内的: EYZ,GT-I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) \qJ^n %
而在存储过程中 &';@CeK
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Ds8x9v)^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) %VrMlG4hx