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。 GbZ;#^S
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一、基础 [V}, tO|
1、说明:创建数据库 iK;opA"
CREATE DATABASE database-name CIC[1,
2、说明:删除数据库 Lx[
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drop database dbname Wf26
3、说明:备份sql server cgT
--- 创建 备份数据的 device s0"e'
USE master u{e-G&]^;
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \>Zvev!s
--- 开始 备份 o
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BACKUP DATABASE pubs TO testBack sen=0SB/
4、说明:创建新表 zI;0&
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) WF2-$`x
根据已有的表创建新表: 4P8*k[.
A:create table tab_new like tab_old (使用旧表创建新表) Jjm|9|C,
B:create table tab_new as select col1,col2... from tab_old definition only K[?Xm"4
5、说明:删除新表 EqB)sK/3
drop table tabname N{Qxq>6 G
6、说明:增加一个列 L>9R4:g
Alter table tabname add column col type ip:LcG t
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。 ;;U:Jtn2
7、说明:添加主键: Alter table tabname add primary key(col) tkKJh !Q7
说明:删除主键: Alter table tabname drop primary key(col) {6Au3gt/
8、说明:创建索引:create [unique] index idxname on tabname(col....) rofNZ;nu
删除索引:drop index idxname rZ03x\2
注:索引是不可更改的,想更改必须删除重新建。 -ysn&d\rV
9、说明:创建视图:create view viewname as select statement [2c{k
删除视图:drop view viewname ROb\Rxm
10、说明:几个简单的基本的sql语句 19U]2D/z
选择:select * from table1 where 范围 !{%: qQiA
插入:insert into table1(field1,field2) values(value1,value2) UQ?%|y*Kc
删除:delete from table1 where 范围 Xrqx\X
更新:update table1 set field1=value1 where 范围 A[N{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ku&k'V
排序:select * from table1 order by field1,field2 [desc]
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总数:select count as totalcount from table1 Xyx"A(v^l
求和:select sum(field1) as sumvalue from table1 ~Ci{3j :]
平均:select avg(field1) as avgvalue from table1 ,FSrn~-j9
最大:select max(field1) as maxvalue from table1 ^+|De}`u
最小:select min(field1) as minvalue from table1 A#y@`}]!'
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11、说明:几个高级查询运算词 k!L@GQ
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A: UNION 运算符 6"
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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。 5<YzalNf
B: EXCEPT 运算符 V9%aBkf8w
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。 ?&+9WJ<M
C: INTERSECT 运算符 :!TIK1
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。 FY3IUG
注:使用运算词的几个查询结果行必须是一致的。 5"KlRuv%
12、说明:使用外连接 2umv|]n+l|
A、left outer join: #1nJ(-D+
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。 6p;m\
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*S"KX$
B:right outer join: X[$++p
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 >bo'Y9C
C:full outer join: _GYMPq\%L#
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 2 -+f1,
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二、提升 ro~+j}*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5]Ajf;W\
法一:select * into b from a where 1<>1 }FqA ppr
法二:select top 0 * into b from a r?$?;%|C
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) w}cY6O,1
insert into b(a, b, c) select d,e,f from b; d l]#
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) Yl cbW0'c
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ki]ti={12
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. k ]a*&me
4、说明:子查询(表名1:a 表名2:b) [\z/Lbn
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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) 8MwK.H[U
5、说明:显示文章、提交人和最后回复时间 ts~{w;c
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [1G^/K"
6、说明:外连接查询(表名1:a 表名2:b) >!6JKL~=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c NZLAk~R;0
7、说明:在线视图查询(表名1:a ) BRRj$)u
select * from (SELECT a,b,c FROM a) T where t.a > 1; |UnUG
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 |bv,2uW z
select * from table1 where time between time1 and time2 bCv {1]RC2
select a,b,c, from table1 where a not between 数值1 and 数值2 E2wz(,@
9、说明:in 的使用方法 "y?\Dx
select * from table1 where a [not] in ('值1','值2','值4','值6') ._Zt=jB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 mu]as: ~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) V&{MQWy
11、说明:四表联查问题: S_(d9GK<
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 ..... KFRw67^
12、说明:日程安排提前五分钟提醒 je,}_:7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 = "ts`>
13、说明:一条sql 语句搞定数据库分页 +a@GHx4-
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 }WLh8i?_
14、说明:前10条记录 dI'SwnR
select top 10 * form table1 where 范围 JH,/jR
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.) ~`MS~,,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) k"UO c=
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 l:B;zi`)oB
(select a from tableA ) except (select a from tableB) except (select a from tableC) 1`0#HSO
17、说明:随机取出10条数据 wucV_p.E
select top 10 * from tablename order by newid() *Nb#W!
18、说明:随机选择记录 $^/0<i$
select newid() <i\A_qqc/
19、说明:删除重复记录 C@\{ehG
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 9=l.T/?sf
20、说明:列出数据库里所有的表名 JAc_kl{4O
select name from sysobjects where type='U' R[tC^]ai
21、说明:列出表里的所有的 l:|D,q
select name from syscolumns where id=object_id('TableName') Nh?|RE0t
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。 QbFHfA2Ij
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 q<vf,D@{ !
显示结果: jyS=!ydn+
type vender pcs fK}h"iH+K
电脑 A 1 -Yi,_#3{
电脑 A 1 OTWkUB{
光盘 B 2 KxGX\
光盘 A 2 XKOUQc4!R
手机 B 3 vT^Sk;E
手机 C 3 Qq& W3
23、说明:初始化表table1 w0m^ &,;#
TRUNCATE TABLE table1 p&p.Q^"ok
24、说明:选择从10到15的记录 :fcM:w&
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc c,EBF\r8*
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三、技巧 -;(Q1)&
1、1=1,1=2的使用,在SQL语句组合时用的较多 ,Z9>h[JF
"where 1=1" 是表示选择全部 "where 1=2"全部不选, &jA\hg#9
如: *hhmTc#
if @strWhere !='' /hW d/H]
begin 4Aes#{R3v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,Dmc2D
end ]:]H:U]p
else #U7_a{cn"M
begin )P&9A)8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' y8Xv~4qQW
end F'8T;J7
我们可以直接写成 >T3H qYX5W
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &Nl2sey
2、收缩数据库 M6|I6M<
--重建索引 5E\#%K[
DBCC REINDEX FVsj;
DBCC INDEXDEFRAG 83~ i:+;
--收缩数据和日志 pcS+o
DBCC SHRINKDB b}9[s
DBCC SHRINKFILE FwAKP>6 *
3、压缩数据库 | $^;wP
dbcc shrinkdatabase(dbname) U
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4、转移数据库给新用户以已存在用户权限 z$lF)r:Bc
exec sp_change_users_login 'update_one','newname','oldname' w?vVVA
go &-l8n^
5、检查备份集 BG`s6aC|z<
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 0>Z ;Ni
6、修复数据库 ]
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ALTER DATABASE [dvbbs] SET SINGLE_USER \{\MxXW
GO hn)a@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK .9G<y 4
GO yTM3^R(
ALTER DATABASE [dvbbs] SET MULTI_USER V3N0Og3
GO o5o^TW{
7、日志清除 w FtN+
SET NOCOUNT ON V\~Wv V
DECLARE @LogicalFileName sysname, oP?YA-#nc
@MaxMinutes INT, OKOu`Hz@
@NewSize INT Z,7R;,qX
USE tablename -- 要操作的数据库名 H[Q_hY[>V
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 r`\A
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. mg:!4O$K
@NewSize = 1 -- 你想设定的日志文件的大小(M) iTo k[uJ}
-- Setup / initialize `s#Hq\C
DECLARE @OriginalSize int m`?MV\^
SELECT @OriginalSize = size A1Y7;-D
FROM sysfiles 2(!fg4#+
WHERE name = @LogicalFileName KU9Z"9#
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Rf %HIAVE
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + hjx)D
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' NtGn88='{
FROM sysfiles
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WHERE name = @LogicalFileName w) ]H ^6
CREATE TABLE DummyTrans 4 {GU6v)f
(DummyColumn char (8000) not null) 4\5uY
DECLARE @Counter INT, C_fY %O
@StartTime DATETIME, V,v[y\
@TruncLog VARCHAR(255) f7de'^t9
SELECT @StartTime = GETDATE(), zzGYiF?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' I8Vb-YeS
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <3X7T6_:@
EXEC (@TruncLog) Rhzn/\)|
-- Wrap the log if necessary. T5Eseesp
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired iX{G]< n
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1t[j"CG(o
AND (@OriginalSize * 8 /1024) > @NewSize 9a$56GnW1
BEGIN -- Outer loop. {NM+Oj,~'
SELECT @Counter = 0 )QiQn=Ce
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,SlN zR
BEGIN -- update 0o&MB
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INSERT DummyTrans VALUES ('Fill Log') =4!nFi
DELETE DummyTrans "O>n@Q|
SELECT @Counter = @Counter + 1 1r)kR@!LNG
END YA(@5CZ
EXEC (@TruncLog) +A_J1iJ<
END )x,8D ~p'
SELECT 'Final Size of ' + db_name() + ' LOG is ' + O{z}8&oR:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + n";02?@F
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,"}Rg1\4t
FROM sysfiles *~$~yM/~3U
WHERE name = @LogicalFileName { >{B`e`$
DROP TABLE DummyTrans )
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SET NOCOUNT OFF _>o-UBb4]T
8、说明:更改某个表 w2(guL($
exec sp_changeobjectowner 'tablename','dbo' ]1-z!B 4K
9、存储更改全部表 =TvzS%U
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ITuq/qts]A
@OldOwner as NVARCHAR(128), cF T 9Lnz
@NewOwner as NVARCHAR(128) {4 >mc'dv
AS bEuaOBc
DECLARE @Name as NVARCHAR(128) R!
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DECLARE @Owner as NVARCHAR(128) %!Q`e79g8
DECLARE @OwnerName as NVARCHAR(128) N@o?b
DECLARE curObject CURSOR FOR xh@-g|+g
select 'Name' = name, eBN)g^
'Owner' = user_name(uid) _#$9 y1bd
from sysobjects bucR">_p
where user_name(uid)=@OldOwner g\A
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order by name YMpf+kN
OPEN curObject \6|/RFT
FETCH NEXT FROM curObject INTO @Name, @Owner ,FQdtNMap
WHILE(@@FETCH_STATUS=0) 0IM8
BEGIN "R
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if @Owner=@OldOwner woH)0v
begin =/Aj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) %T`U^Pnr
exec sp_changeobjectowner @OwnerName, @NewOwner s0UFym8
end qd@&59zSh
-- select @name,@NewOwner,@OldOwner )4Q?aMm
FETCH NEXT FROM curObject INTO @Name, @Owner o;F" {RZ
END a5'#j35
close curObject hm$X]H`uMX
deallocate curObject
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GO pe0x""K
10、SQL SERVER中直接循环写入数据 jD,Baz<
declare @i int n;XWMY
set @i=1 *mG`_9
while @i<30 /Poet%XvRx
begin (3vHY`9
insert into test (userid) values(@i) &7?R+ZGo
set @i=@i+1 (n(
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end z;u>
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小记存储过程中经常用到的本周,本月,本年函数 JeH;v0
Dateadd(wk,datediff(wk,0,getdate()),-1) t/i5,le
Dateadd(wk,datediff(wk,0,getdate()),6) V%
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Dateadd(mm,datediff(mm,0,getdate()),0) %n0;[sD0A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;bu#8,
Dateadd(yy,datediff(yy,0,getdate()),0) r~[vaQQ6L
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) m,LG=s
上面的SQL代码只是一个时间段 ig"uXs
Dateadd(wk,datediff(wk,0,getdate()),-1) d=.2@Ry
Dateadd(wk,datediff(wk,0,getdate()),6) 3Q}$fQ&S
就是表示本周时间段. e>'H
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下面的SQL的条件部分,就是查询时间段在本周范围内的: ^u)z{.z'H/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) qf'm=efRyu
而在存储过程中 5@osnf?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) {WN(&eax
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) -!qu"A: