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。 @JdZ5Q
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一、基础 Ar~"R4!
1、说明:创建数据库 ]l8^KX'
CREATE DATABASE database-name -W>'^1cR
2、说明:删除数据库 _V`DWR
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drop database dbname (5\NB0
3、说明:备份sql server [z7bixN
--- 创建 备份数据的 device ID/F
USE master O*#*%RL|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 6AocmR0D'
--- 开始 备份 aMTu-hA
BACKUP DATABASE pubs TO testBack )=Jk@yj8x
4、说明:创建新表 %D * OO{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5h; +Ky!I
根据已有的表创建新表: 7 [0L9\xm
A:create table tab_new like tab_old (使用旧表创建新表) ;J7F J3n
B:create table tab_new as select col1,col2... from tab_old definition only orb_"Qw
5、说明:删除新表 )p*}e8L
drop table tabname Y".RPiTL
6、说明:增加一个列 y|wc,n%L>
Alter table tabname add column col type {s;U~!3aY
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。 *g^x*|f6
7、说明:添加主键: Alter table tabname add primary key(col) 1) Zf3Y8
说明:删除主键: Alter table tabname drop primary key(col) @V!r"Bkg.
8、说明:创建索引:create [unique] index idxname on tabname(col....) _o8?E&d
删除索引:drop index idxname 1@$Ko5
注:索引是不可更改的,想更改必须删除重新建。 ZRYEqSm
9、说明:创建视图:create view viewname as select statement ++E3]X|
删除视图:drop view viewname Pi|o` d
10、说明:几个简单的基本的sql语句 4!KoFoZt*
选择:select * from table1 where 范围 q:g2Zc'Y~W
插入:insert into table1(field1,field2) values(value1,value2) J[&b`A@.o
删除:delete from table1 where 范围 Dih3}X&jn$
更新:update table1 set field1=value1 where 范围 }}<z/zN&^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! --DoB=5%8
排序:select * from table1 order by field1,field2 [desc] ^b
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总数:select count as totalcount from table1 xMBaVlEN
求和:select sum(field1) as sumvalue from table1 =z8f]/k*>
平均:select avg(field1) as avgvalue from table1 M8u<qj&<O
最大:select max(field1) as maxvalue from table1 k!{p7*0
最小:select min(field1) as minvalue from table1 k?7 X3/O
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11、说明:几个高级查询运算词 $.bBFWk
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A: UNION 运算符 YX#-nyK
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 n?c]M
B: EXCEPT 运算符 bwl|0"f+`
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 t2"FXTAq
C: INTERSECT 运算符 iJ~Vl"|m
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 2;?I>~
注:使用运算词的几个查询结果行必须是一致的。 qcT'nZ:
12、说明:使用外连接 ,\@O(;
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A、left outer join: FKmFo^^0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 bAx?&$
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 Y5j]Z^^v
B:right outer join: v~Y^r2
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。 GDuMY\1
C:full outer join: &
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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。 5+wAzVA
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二、提升 {,L+1h
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Kde9
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法一:select * into b from a where 1<>1 wT{nu[=GH*
法二:select top 0 * into b from a ZGd!IghL
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &:7ZQ1
insert into b(a, b, c) select d,e,f from b; r4#o+qE
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) q?ix$nKOv
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 vz!s~cAt
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Kx%Sku<F'
4、说明:子查询(表名1:a 表名2:b) G2FXrkU
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ]H1I,`=@
5、说明:显示文章、提交人和最后回复时间 +="e]Yh;
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ]i)j3WDz]
6、说明:外连接查询(表名1:a 表名2:b) W='>:H
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6!(@@^7{*
7、说明:在线视图查询(表名1:a ) piZJJYv t
select * from (SELECT a,b,c FROM a) T where t.a > 1; vZBc!AW
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 +) m_o"hl
select * from table1 where time between time1 and time2 3F<VH
select a,b,c, from table1 where a not between 数值1 and 数值2 |*0<M(YXN
9、说明:in 的使用方法 "%x<ttLl
select * from table1 where a [not] in ('值1','值2','值4','值6') y?q*WUh
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0/oyf]HR
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) bv*,#Qm
11、说明:四表联查问题: yiA<,!;4P
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... @Rw!'T
12、说明:日程安排提前五分钟提醒 ,YMp<C
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 eh5gjSqx
13、说明:一条sql 语句搞定数据库分页 *v3]}g[<
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 s]JF0584
14、说明:前10条记录 qC?:*CXH
select top 10 * form table1 where 范围 ~7Tc$
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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.) = MOj|NR [
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ,9o"43D:a|
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 smDw<slC
(select a from tableA ) except (select a from tableB) except (select a from tableC) >lIk9|
17、说明:随机取出10条数据 }7.PH'.8
select top 10 * from tablename order by newid() 5>\/[I/!
18、说明:随机选择记录 Zc`BiLzrIG
select newid() [ra_ 2R
19、说明:删除重复记录 w:<W.7y?0
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) k'5?M
20、说明:列出数据库里所有的表名 $+I;oHWI
select name from sysobjects where type='U' _n` a`2C|m
21、说明:列出表里的所有的 byfJy^8G
select name from syscolumns where id=object_id('TableName') a)'5Nw9*
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。 7[}xP#Z
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 IDG}ZlG
显示结果: 4sT88lG4n
type vender pcs ;hjwD
电脑 A 1 oczN5YSt
电脑 A 1 :65~[$2
光盘 B 2 ynhmMy%
光盘 A 2 #hsx#x||
手机 B 3 %GS(:]{n
手机 C 3 ML>[^F
23、说明:初始化表table1 <h'5cO
TRUNCATE TABLE table1 a,WICv0E
24、说明:选择从10到15的记录 #Q`dku%V:
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc y;o^- O
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三、技巧 9^G/8<^^>
1、1=1,1=2的使用,在SQL语句组合时用的较多 u!W0P6
"where 1=1" 是表示选择全部 "where 1=2"全部不选, AQ[GO6$,%H
如: !_cg\KU#
if @strWhere !='' LpqO{#ZG
begin lH6OcD:kj
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere pj?f?.^
end
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else csW43&
begin u2?|Ue@[
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Y*vW!yu
end Ot6aRk
我们可以直接写成 MfWyc_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S-|)QGxV6
2、收缩数据库 LB a[:j2
--重建索引 ?qWfup\S
DBCC REINDEX = < oBgD0k
DBCC INDEXDEFRAG 4k@5/5zsM
--收缩数据和日志 <yH4HY
DBCC SHRINKDB
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DBCC SHRINKFILE "\o+v|;
3、压缩数据库 TO?R({yx*
dbcc shrinkdatabase(dbname) 0p}D(m2B
4、转移数据库给新用户以已存在用户权限 &bfA.&
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exec sp_change_users_login 'update_one','newname','oldname' qtQ6cqLd
go #nPQ!NB/
5、检查备份集 Bx4w)9+3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' SX#
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6、修复数据库 a+Kj1ix
ALTER DATABASE [dvbbs] SET SINGLE_USER yooX$
GO <BMXCk
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9E"vN
GO "q.\>MCv
ALTER DATABASE [dvbbs] SET MULTI_USER .xm.DRk3
GO V#S9H!hm$
7、日志清除 ov_j4j>6P
SET NOCOUNT ON &p4&[H?
DECLARE @LogicalFileName sysname, rFj-kojg
@MaxMinutes INT, <?riU\-]y
@NewSize INT %~2YE
USE tablename -- 要操作的数据库名 ~^r29'3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 f-`)^5E
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #\ X#w<\?
@NewSize = 1 -- 你想设定的日志文件的大小(M) J:V6
-- Setup / initialize :?g:~+hfO
DECLARE @OriginalSize int pH"#8O&
SELECT @OriginalSize = size K,:cJ
FROM sysfiles 5?3Me59
WHERE name = @LogicalFileName A|X">,A
SELECT 'Original Size of ' + db_name() + ' LOG is ' + H?&Mbw
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + AK*LyR?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rMLp-aR'
FROM sysfiles .ZVUd84B
WHERE name = @LogicalFileName Pa
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CREATE TABLE DummyTrans C(#u[8
(DummyColumn char (8000) not null) a!"$~y$*
DECLARE @Counter INT, @M_oH:GV
@StartTime DATETIME, 0 Tx{3#
@TruncLog VARCHAR(255) LHkc7X$
SELECT @StartTime = GETDATE(), %'s>QF]'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3TY5 ;6
DBCC SHRINKFILE (@LogicalFileName, @NewSize) gT0BkwIV
EXEC (@TruncLog) m
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-- Wrap the log if necessary. }dWq=)*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired SEGri#s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) w&o&jAb-M
AND (@OriginalSize * 8 /1024) > @NewSize N D(/uyI
BEGIN -- Outer loop. -ZRO@&tMD
SELECT @Counter = 0 S||}nJ0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C9n?@D;S
BEGIN -- update rA5=dJ"I
INSERT DummyTrans VALUES ('Fill Log') \KQ71yqY
DELETE DummyTrans @Z\,q's
SELECT @Counter = @Counter + 1 V C24sU
END {f2S/$q
EXEC (@TruncLog) clL2k8VS
END g!?:Ye`5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + tG9BfGF
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + jv%kOovj
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -EkWs/'h
FROM sysfiles <SgM@0m
WHERE name = @LogicalFileName t>urc
DROP TABLE DummyTrans W&&;:Fr
SET NOCOUNT OFF f78An 8
8、说明:更改某个表 jr /pj?
exec sp_changeobjectowner 'tablename','dbo' q_g+Jf
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9、存储更改全部表 Y2ZT.l
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch pb
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@OldOwner as NVARCHAR(128), bF"G[pD
@NewOwner as NVARCHAR(128) aWWU4xe
AS T92UeG
DECLARE @Name as NVARCHAR(128) _wkVwPr
DECLARE @Owner as NVARCHAR(128) )Ch2E|C?=8
DECLARE @OwnerName as NVARCHAR(128) u09:Z{tL;@
DECLARE curObject CURSOR FOR F+,~v-
select 'Name' = name, '_w=k4
'Owner' = user_name(uid) Ma.`A
from sysobjects P@$/P99
where user_name(uid)=@OldOwner xLNtIzx
order by name Tx|Ir+f6L
OPEN curObject juka0/
FETCH NEXT FROM curObject INTO @Name, @Owner hb zC#@q
WHILE(@@FETCH_STATUS=0) a(kg/s
BEGIN }XV+gyG=@
if @Owner=@OldOwner EQb7-vhg
begin :PIF07$xl
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8\^}~s$$A
exec sp_changeobjectowner @OwnerName, @NewOwner [SHXJ4P*
end }=gx#
-- select @name,@NewOwner,@OldOwner s+,OxRVw(
FETCH NEXT FROM curObject INTO @Name, @Owner OGde00
END s>;v!^N?u
close curObject h]+C.Eqnt#
deallocate curObject }!"A! ~&
GO -8:&>~4`
10、SQL SERVER中直接循环写入数据 @kpv{`Y
declare @i int =XucOli6
set @i=1 Q&wB$*u
while @i<30 %{AO+u2i
begin qq) rd
insert into test (userid) values(@i) *.sVr7=j
set @i=@i+1 6x h:/j3
end }.3nthgz
小记存储过程中经常用到的本周,本月,本年函数 tZ=E')!\
Dateadd(wk,datediff(wk,0,getdate()),-1) Gn|F`F
Dateadd(wk,datediff(wk,0,getdate()),6) uD1e!oU
Dateadd(mm,datediff(mm,0,getdate()),0) 4L ;% h
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $@^pAP
Dateadd(yy,datediff(yy,0,getdate()),0) x_|UPF
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ORyE`h
上面的SQL代码只是一个时间段 WG N=Y~E
Dateadd(wk,datediff(wk,0,getdate()),-1) M=1n QF2J
Dateadd(wk,datediff(wk,0,getdate()),6) 8YZbP5'
就是表示本周时间段. u.d).da
下面的SQL的条件部分,就是查询时间段在本周范围内的: ]h>_\9qO
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) T&%ux=Jt
而在存储过程中 A?CcHw
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?WF/|/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) jhXkSj