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。 ydyG}XI7V
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一、基础 G g(NGT
1、说明:创建数据库 lJlhl7
CREATE DATABASE database-name XD
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2、说明:删除数据库 7?,7TR2Ny
drop database dbname T;J7+0
3、说明:备份sql server ;/R kMS
--- 创建 备份数据的 device [\a:4vDAbi
USE master 9u?Eb~#$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' V07VwVD
--- 开始 备份 U Q)!|@&
BACKUP DATABASE pubs TO testBack 9p4%8WhJ
4、说明:创建新表 L7<+LA)s0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r:73uRk
根据已有的表创建新表: W
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A:create table tab_new like tab_old (使用旧表创建新表) dK`(BA{`3
B:create table tab_new as select col1,col2... from tab_old definition only _TrZ'iL}T
5、说明:删除新表 ovB=Zm
drop table tabname 8-A:k E
6、说明:增加一个列 NtqFnxm/
Alter table tabname add column col type *.:! Ax
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。
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7、说明:添加主键: Alter table tabname add primary key(col) */4tJG1U
说明:删除主键: Alter table tabname drop primary key(col) #s*k|
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8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname K[*h+YO
注:索引是不可更改的,想更改必须删除重新建。 k{_1r;
9、说明:创建视图:create view viewname as select statement 40R"^*
删除视图:drop view viewname gji*Wq
10、说明:几个简单的基本的sql语句 ~m!#FTc*
选择:select * from table1 where 范围 /q T E
插入:insert into table1(field1,field2) values(value1,value2) /9P^{OZ;y
删除:delete from table1 where 范围 QjI#Cs}w
更新:update table1 set field1=value1 where 范围 1]Gf)|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Ywmyr[Uh'
排序:select * from table1 order by field1,field2 [desc] kp'b>&9r
总数:select count as totalcount from table1 $y8mK|3.3u
求和:select sum(field1) as sumvalue from table1 3\,MsoAl
平均:select avg(field1) as avgvalue from table1 E1#H{)G
最大:select max(field1) as maxvalue from table1 cT\Ov
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最小:select min(field1) as minvalue from table1 5QKRI)XpZ
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11、说明:几个高级查询运算词 S> .q5
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A: UNION 运算符 BO[+E'2
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。 ?){0-A4
B: EXCEPT 运算符 2@rp<&s
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。 Rk}\)r\
C: INTERSECT 运算符 >9 q]>fJ
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。 NAJ '><2
注:使用运算词的几个查询结果行必须是一致的。 |!{z?
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12、说明:使用外连接 GVeL~Q
A、left outer join: kZJt~}
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。 7F,07\c
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 4 U3C~J
B:right outer join: yZ?xt'tn
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。 9
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C:full outer join: ~&t!$
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。 +G<}JJ'V
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二、提升 wYZy e^7
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) FX{~"
法一:select * into b from a where 1<>1 mk#>Dpy?
法二:select top 0 * into b from a s>LA3kT
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <l*agH-.3
insert into b(a, b, c) select d,e,f from b; Kl4isGcr]
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) `)0Rv|?
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 U*
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. V*~1,6N[
4、说明:子查询(表名1:a 表名2:b) <ED8"~_
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) ,O$Z,J4VL
5、说明:显示文章、提交人和最后回复时间 ^wvH,>Yo
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _{N0OX
6、说明:外连接查询(表名1:a 表名2:b) lo\: ]/&6
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6"BtfQ")
7、说明:在线视图查询(表名1:a ) I8%d;G~
select * from (SELECT a,b,c FROM a) T where t.a > 1; w%>aR_G
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 qFV;n6&V
select * from table1 where time between time1 and time2 j)g_*\tQ
select a,b,c, from table1 where a not between 数值1 and 数值2 5LDQ^n
9、说明:in 的使用方法 ?| D$#{^
select * from table1 where a [not] in ('值1','值2','值4','值6') ZC3tbhV
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<$wz/\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) aR`_h=a
11、说明:四表联查问题: ;k9
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... E"Ya-8d=
12、说明:日程安排提前五分钟提醒 6a "VCE]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 FZ[@])B
13、说明:一条sql 语句搞定数据库分页 Fpy6"Z?z
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 TYs+XJ'Xj
14、说明:前10条记录 _fczE~O/
select top 10 * form table1 where 范围 ;cM8EU^.
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) BSx j~pun
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )e4WAlg8c
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ti$oZ4PpF
(select a from tableA ) except (select a from tableB) except (select a from tableC) XNc"kp? z
17、说明:随机取出10条数据 (|yRo
select top 10 * from tablename order by newid() $=e&q
18、说明:随机选择记录 nz,Mqol
select newid() \_m\U.*
19、说明:删除重复记录 .b=M5JsyV
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 'hwV
20、说明:列出数据库里所有的表名 3v8V*48B$
select name from sysobjects where type='U' ?noETH z)
21、说明:列出表里的所有的 !Iw{Y'
select name from syscolumns where id=object_id('TableName') Q3<bC6$r
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 mQwk!* U
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type k| _$R?
显示结果: 21[K[ %
type vender pcs YtwmlIar`
电脑 A 1 |i,zY{GI+2
电脑 A 1 `c qH}2s#
光盘 B 2 WUE)SVf
光盘 A 2 AijPN
手机 B 3 oj,HJH+
手机 C 3 uR06&SaA>
23、说明:初始化表table1 P#dG]NMf
TRUNCATE TABLE table1 q7 %=`l
24、说明:选择从10到15的记录 u+2xrzf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {
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三、技巧 ?V&Ld$db
1、1=1,1=2的使用,在SQL语句组合时用的较多 w6WGFQ_ %
"where 1=1" 是表示选择全部 "where 1=2"全部不选, *6 z'+'
如: 8k+q7
if @strWhere !='' _Ewy^;S%L
begin Pi&fwGL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #hy5c,}>
end LW83Y/7
else ^D]7pe
begin )V[w:= *
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 2- Npw%;
end p"hm.=,
我们可以直接写成 x*,q
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere n&2=6$*,k
2、收缩数据库 4*N@=v
--重建索引 *@bg/S
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DBCC REINDEX _g^K$+F'}
DBCC INDEXDEFRAG X <ba|(
--收缩数据和日志 ),D`ZRXS
DBCC SHRINKDB G<">/_jn
DBCC SHRINKFILE E i\J9zt
3、压缩数据库 Y5h)l<P>B
dbcc shrinkdatabase(dbname) K^]?@oHO
4、转移数据库给新用户以已存在用户权限 BRo
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exec sp_change_users_login 'update_one','newname','oldname' V',m $
go N8DiEB3~
5、检查备份集 S+_A
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $+!}Vtb
6、修复数据库 ]Vf8mkDGO
ALTER DATABASE [dvbbs] SET SINGLE_USER xVHQ[I%
GO &P,4EaC9;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 7)8rc(58
GO bOdsMlJkN
ALTER DATABASE [dvbbs] SET MULTI_USER JL]k:i^`A
GO ^V XXq
7、日志清除 $ sA~p_]
SET NOCOUNT ON xvdnEaWe$
DECLARE @LogicalFileName sysname, }OX>(
@MaxMinutes INT, %4r!7X|O<
@NewSize INT
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USE tablename -- 要操作的数据库名 Q8DQ .C
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. i)`zKbK
@NewSize = 1 -- 你想设定的日志文件的大小(M) ZaNyNxbp>z
-- Setup / initialize _Sk<S
DECLARE @OriginalSize int U47k5s(J
SELECT @OriginalSize = size RBv=
FROM sysfiles 35@Ibe~
WHERE name = @LogicalFileName `3>)BV<P
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "u,~yxYWl
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &23ss/
FROM sysfiles H~_^w.P
WHERE name = @LogicalFileName 1CS]~1Yp:
CREATE TABLE DummyTrans N8L)KgM5#7
(DummyColumn char (8000) not null) w=P<4bdT
DECLARE @Counter INT, ~qLhZR\g^
@StartTime DATETIME, (W}i287
@TruncLog VARCHAR(255) `MpC<sit
SELECT @StartTime = GETDATE(), *{;A\sL
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $CQwBsYb=
DBCC SHRINKFILE (@LogicalFileName, @NewSize) QLpTz"H
EXEC (@TruncLog) /J9T=N
-- Wrap the log if necessary. L/ICFa.G
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired RQK**
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )Ido|!]0d
AND (@OriginalSize * 8 /1024) > @NewSize @x-GbK?
BEGIN -- Outer loop. Kz*AzB
SELECT @Counter = 0 6 peM4X
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) H{tOCYyD
BEGIN -- update gU 2c--`
INSERT DummyTrans VALUES ('Fill Log') kmwrv -W
DELETE DummyTrans `w+9j-
SELECT @Counter = @Counter + 1 W%jX-
END KxTYc
EXEC (@TruncLog) RWh}?vs_
END yV]-Oa$*s0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + T=p}By3a
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + o j4)7{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9:Z~}yX
FROM sysfiles Mb/6>
WHERE name = @LogicalFileName d[Fr
DROP TABLE DummyTrans [q+39
SET NOCOUNT OFF r0$9c
8、说明:更改某个表 PA-0FlV|
exec sp_changeobjectowner 'tablename','dbo' ]#7Y@Yo
9、存储更改全部表 _ L:w;Oy9T
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "}x70q'>S
@OldOwner as NVARCHAR(128), 6~Oje>w;
@NewOwner as NVARCHAR(128) fvBC9^3
AS fN%5D z-e
DECLARE @Name as NVARCHAR(128) OFAqP1o{$
DECLARE @Owner as NVARCHAR(128) hpi_0lMkI
DECLARE @OwnerName as NVARCHAR(128) +&zuI
DECLARE curObject CURSOR FOR .STf
select 'Name' = name, H><mcah
'Owner' = user_name(uid) hG3$ ]i9
from sysobjects |(w#NE5
where user_name(uid)=@OldOwner ?bYQZJ>&
order by name ;@-5lCvC(+
OPEN curObject kd4*Zab
FETCH NEXT FROM curObject INTO @Name, @Owner OsSiBb,W79
WHILE(@@FETCH_STATUS=0) te4"+[ $|
BEGIN Pc
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if @Owner=@OldOwner J1ro\"
begin ]~ 8N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Mw7UU1 ei
exec sp_changeobjectowner @OwnerName, @NewOwner xcRrI|?eC
end [Ik
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-- select @name,@NewOwner,@OldOwner \^W?
FETCH NEXT FROM curObject INTO @Name, @Owner aTL7"Myp
END oW1olmpp=
close curObject (2\ekct ^
deallocate curObject R/FV'qy]
GO EBE>&{%$^
10、SQL SERVER中直接循环写入数据 r|BKp,u9
declare @i int gY^TBR0?m
set @i=1 90696v.
while @i<30 x=|@AFI
begin 5:3$VWLa
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insert into test (userid) values(@i) NbMH@6%E
set @i=@i+1 ;j\$[4W.i
end g#nsA(_L
小记存储过程中经常用到的本周,本月,本年函数 .{ L m
Dateadd(wk,datediff(wk,0,getdate()),-1) 6 FxndR;
Dateadd(wk,datediff(wk,0,getdate()),6) x(6.W"-S
Dateadd(mm,datediff(mm,0,getdate()),0) `l40awGCz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) {$=%5
Dateadd(yy,datediff(yy,0,getdate()),0) aL6 5t\2
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >a~FSZf
上面的SQL代码只是一个时间段 ! r\ktX
Dateadd(wk,datediff(wk,0,getdate()),-1) (&x\,19U$
Dateadd(wk,datediff(wk,0,getdate()),6) F9%VyQf
就是表示本周时间段. aVL%-Il}
下面的SQL的条件部分,就是查询时间段在本周范围内的: l zknB
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) I}3K,w/7mi
而在存储过程中 rxA)&