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。 FHU6o910
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一、基础 8>[g/%W
1、说明:创建数据库 :p}8#rb
CREATE DATABASE database-name .\_RavW23
2、说明:删除数据库 ou-UR5
drop database dbname z
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3、说明:备份sql server m=l'9j"D
--- 创建 备份数据的 device ,\v'%,:C
USE master $2h%IK>#G
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Gu~*ZKyJ
--- 开始 备份 RVV`
BACKUP DATABASE pubs TO testBack Godrz*"
4、说明:创建新表 0)Ephsw
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
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根据已有的表创建新表: an"~n`g
A:create table tab_new like tab_old (使用旧表创建新表) #}y8hzS$
B:create table tab_new as select col1,col2... from tab_old definition only PhC3F4
5、说明:删除新表 8-x-?7
drop table tabname A811VL^
6、说明:增加一个列 ` 'Qb?F6
Alter table tabname add column col type [-$
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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。 ?'P}ZC8P
7、说明:添加主键: Alter table tabname add primary key(col) &;-zy%#l
说明:删除主键: Alter table tabname drop primary key(col) nte?a e
8、说明:创建索引:create [unique] index idxname on tabname(col....) +v;z^+
删除索引:drop index idxname =|agW.l
注:索引是不可更改的,想更改必须删除重新建。 d:';s~
9、说明:创建视图:create view viewname as select statement _aPAn|.
删除视图:drop view viewname :Mu*E5
10、说明:几个简单的基本的sql语句 nFn!6,>E
选择:select * from table1 where 范围 X-HE9PT.
插入:insert into table1(field1,field2) values(value1,value2) y,nmPX?]n
删除:delete from table1 where 范围 xW`y7Q }p
更新:update table1 set field1=value1 where 范围 h )
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! u)0I$Tc"
排序:select * from table1 order by field1,field2 [desc] )cJ>&g4]
总数:select count as totalcount from table1 B}d&tH2^s
求和:select sum(field1) as sumvalue from table1 {=[>N>"
平均:select avg(field1) as avgvalue from table1 @zg}x0]
最大:select max(field1) as maxvalue from table1 }9S}?R
最小:select min(field1) as minvalue from table1 a<G&}|6
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11、说明:几个高级查询运算词 >Wr%usNxc
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A: UNION 运算符 Xi&J%N'
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 y>a?<*Y+e
B: EXCEPT 运算符 S!b18|o"
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 9wWBE<}>u
C: INTERSECT 运算符
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ~29p|X<
注:使用运算词的几个查询结果行必须是一致的。 ~ skp}g]
12、说明:使用外连接 y"JR kJ
A、left outer join: >aVgI<
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 yn62NyK
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (wDE!H7
B:right outer join: +"?+Be
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 >pU9}2fpT
C:full outer join: !__0Vk[s
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 OBWWcL-
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二、提升 8 t5kou]h
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 3"y 6|e/5
法一:select * into b from a where 1<>1 j#](Q!
法二:select top 0 * into b from a PXb$]HV
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) T D_@0Rd
insert into b(a, b, c) select d,e,f from b; \fA{ sehdL
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) 8-2`S*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )%7P?^>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. HxG8'G
4、说明:子查询(表名1:a 表名2:b) YFO{i-*q
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) .hl_zc#
5、说明:显示文章、提交人和最后回复时间 EbC!tR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b WK>F0xMs1
6、说明:外连接查询(表名1:a 表名2:b) d?2V2`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 7>E.0DP
7、说明:在线视图查询(表名1:a ) Mbi]EZ
select * from (SELECT a,b,c FROM a) T where t.a > 1; [^5\Ww
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 ^ Bx[%
select * from table1 where time between time1 and time2 Q.mJ7T~T
select a,b,c, from table1 where a not between 数值1 and 数值2 QZ a.c
9、说明:in 的使用方法 d!,t_jM0
select * from table1 where a [not] in ('值1','值2','值4','值6') )[Y B&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Ed9Uw7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) % MHb
11、说明:四表联查问题: ;P@]7vkff
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 ..... sXIYl% d
12、说明:日程安排提前五分钟提醒 (j:
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,erw(7}'.
13、说明:一条sql 语句搞定数据库分页 FwCb$yE#M
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ?8b19DMK6
14、说明:前10条记录 "/W[gP[y%
select top 10 * form table1 where 范围 =6%oW2E\
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) FcDS*ZEk!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ]R__$fl`8
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 H];B?G';C
(select a from tableA ) except (select a from tableB) except (select a from tableC) y>^a~}Zq
17、说明:随机取出10条数据 Zi!Ta"}8
select top 10 * from tablename order by newid() aB9!}3@
18、说明:随机选择记录 xs$$fPAQ
select newid() ($[wCHU`!
19、说明:删除重复记录 C-'hXh;hQ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w0pMH p'Y
20、说明:列出数据库里所有的表名 KpLmpK1
select name from sysobjects where type='U' _VtQMg|u
21、说明:列出表里的所有的 8%?y)K^
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select name from syscolumns where id=object_id('TableName') o2 14V \
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。 bx@l6bpQ
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 TJ|Jv8j<s
显示结果: ()3\(d5e
type vender pcs
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电脑 A 1 Vz{+3vfra6
电脑 A 1 :2 ;Jo^6Se
光盘 B 2 [6/QUD8
光盘 A 2 EY}:aur
手机 B 3 XYE|=Tr]
手机 C 3 =OVDJ0ozZ
23、说明:初始化表table1 eL!41_QI
TRUNCATE TABLE table1 AOf4y&B>q
24、说明:选择从10到15的记录 r~w.J+W
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L*nK>
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三、技巧 W:w~ M'o
1、1=1,1=2的使用,在SQL语句组合时用的较多 zM0NRERi
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r-2k<#^r
如: x-^6U
if @strWhere !='' C*9X;+S0J
begin D7Q+w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &y[NCAeA
end +2tQFV;
else *Cy54Z#
begin :yay:3qv
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' h8rW"8Th
end d@%"B($nR
我们可以直接写成 }r}*=;Ea
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere sFU< PgV
2、收缩数据库 =TB_|`5;j
--重建索引 qA*~B'
DBCC REINDEX F_-Lu]*
DBCC INDEXDEFRAG JJ.8V72;!Z
--收缩数据和日志
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DBCC SHRINKDB -(VJ,)8t2
DBCC SHRINKFILE ul{x|R
3、压缩数据库 ^:nc'C gP
dbcc shrinkdatabase(dbname) SnCwoxK
4、转移数据库给新用户以已存在用户权限 :=QX ^*
exec sp_change_users_login 'update_one','newname','oldname' OATdmHW
go jm0p%%z
5、检查备份集 _=v#"l
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ]5!3|UYS
6、修复数据库 /-=fWtA
ALTER DATABASE [dvbbs] SET SINGLE_USER XxqGsGx4
GO ZsGvv]P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (Wzp sDte
GO >A#5` $i
ALTER DATABASE [dvbbs] SET MULTI_USER _0/unJl`
GO P5S]h
7、日志清除 '3.\+^3
SET NOCOUNT ON $:ush"=f8^
DECLARE @LogicalFileName sysname, s.3"2waZ=T
@MaxMinutes INT, ]5Cr$%H=
@NewSize INT _\!]MV
USE tablename -- 要操作的数据库名 ,GbmL8P7Y
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 56.!L
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 0.GFg${v`
@NewSize = 1 -- 你想设定的日志文件的大小(M) z2=bbm:
-- Setup / initialize `FHudSK
DECLARE @OriginalSize int F^ q{[Z
SELECT @OriginalSize = size MlO OB
FROM sysfiles CEy\1D
WHERE name = @LogicalFileName f@*69a8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;p`1Y<d-O
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ~uQ*u.wi
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' )'shpRB;1
FROM sysfiles gt kV=V
WHERE name = @LogicalFileName |}"YUk^
CREATE TABLE DummyTrans kUT2/3Vi
(DummyColumn char (8000) not null) X2w)J?pv
DECLARE @Counter INT, 6Yai?*.Q
@StartTime DATETIME, ;?h[WIy
@TruncLog VARCHAR(255) MBLZ:A |
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SELECT @StartTime = GETDATE(), xJq|,":gj
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' D:P(;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) qpQ;,8X-"
EXEC (@TruncLog) 9#8vPjXW}.
-- Wrap the log if necessary. )>a~ %~:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired x6ghO-s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j#HXuV6
AND (@OriginalSize * 8 /1024) > @NewSize }1a}pm2p
BEGIN -- Outer loop. .jrNi=BP*
SELECT @Counter = 0 .#EU@Hc
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -FeXG#{)
BEGIN -- update <z Gh}.6v
INSERT DummyTrans VALUES ('Fill Log') R >x d*A
DELETE DummyTrans 7Sdo*z
SELECT @Counter = @Counter + 1 A U~DbU0O
END fRp]
EXEC (@TruncLog) I{Du/"r#
END n,I3\l9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9>RkFV
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + $b8[/],
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' emSq{A
FROM sysfiles Kda'N$|`
WHERE name = @LogicalFileName mc{z
DROP TABLE DummyTrans K3&xe(
SET NOCOUNT OFF $4bc!
8、说明:更改某个表 F:j@ JMpQ
exec sp_changeobjectowner 'tablename','dbo' Pz)lq2Zm9
9、存储更改全部表 h nydH-;cz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @]uqC~a^
@OldOwner as NVARCHAR(128), g*k)ws
@NewOwner as NVARCHAR(128) AXyXK??
AS {16a P
DECLARE @Name as NVARCHAR(128) WjD885Xo
DECLARE @Owner as NVARCHAR(128) )~2\4t4|g
DECLARE @OwnerName as NVARCHAR(128) \JLGw1F
DECLARE curObject CURSOR FOR @K;b7@4y
select 'Name' = name, `}X3f#eO&
'Owner' = user_name(uid) 5es t
from sysobjects W"\~O"a
where user_name(uid)=@OldOwner 5xH=w:
order by name fit{n]g
OPEN curObject Nd8>p.iqO
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) 8/e-?2l
BEGIN EQ%o oAb8
if @Owner=@OldOwner <G})$f'x2
begin wAh]C;+{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) zB.cOMx
exec sp_changeobjectowner @OwnerName, @NewOwner LV}R 9f
end fA=Z):w
-- select @name,@NewOwner,@OldOwner 9QQ XB-
FETCH NEXT FROM curObject INTO @Name, @Owner Xv1vq
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END m*^)#
close curObject x $uhkP
deallocate curObject 7# AIX],
GO =D<0&M9C
10、SQL SERVER中直接循环写入数据 ]545:)Q1
declare @i int (\\;A?
set @i=1 D4%J!L<P
while @i<30 Y ^^4n$
begin 4m*)("H
insert into test (userid) values(@i) XkI'm\W
set @i=@i+1 Q)75?mn
end yan^\)HZ
小记存储过程中经常用到的本周,本月,本年函数 xHgC':l(0
Dateadd(wk,datediff(wk,0,getdate()),-1) (p]FI# y
Dateadd(wk,datediff(wk,0,getdate()),6) ?Y"%BS+pt
Dateadd(mm,datediff(mm,0,getdate()),0) 161P%sGx2
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,Ckcc
Dateadd(yy,datediff(yy,0,getdate()),0) D
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) WD5J2EePT
上面的SQL代码只是一个时间段 (MGgr
Dateadd(wk,datediff(wk,0,getdate()),-1) J[lC$X[
Dateadd(wk,datediff(wk,0,getdate()),6) Hq.rG-,p
就是表示本周时间段. eV7;#w<]
下面的SQL的条件部分,就是查询时间段在本周范围内的: Vr2A7kq
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) gP_N|LuF"
而在存储过程中 ^\}MG!l
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Q68~D.V%r
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {4_s:+v0