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。 Yn0iu$;n
L@ejFXQg
\Xr*1DI<
一、基础 >t%@)]*N
1、说明:创建数据库 IlB*JJnl
CREATE DATABASE database-name .Sv/0&O
2、说明:删除数据库 @18}'k
drop database dbname #qK5i1<
3、说明:备份sql server \: B))y?}d
--- 创建 备份数据的 device Q5sJ|]Bc
USE master nUisC5HW
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' FJT0lC
--- 开始 备份 %'S[f
BACKUP DATABASE pubs TO testBack b"B:DDw00
4、说明:创建新表 @3S:W2k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SzfMQ@~
根据已有的表创建新表: _sY;
dS/
A:create table tab_new like tab_old (使用旧表创建新表) QFgKEUNgl
B:create table tab_new as select col1,col2... from tab_old definition only 1y,/|Y
5、说明:删除新表 3UUN@Tx
drop table tabname "^Y zHq6
6、说明:增加一个列 P'*Fd3B#A=
Alter table tabname add column col type uH[:R vC0
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 7 y$a=+D i
7、说明:添加主键: Alter table tabname add primary key(col) J@#rOOu
说明:删除主键: Alter table tabname drop primary key(col) $\M];S=CY
8、说明:创建索引:create [unique] index idxname on tabname(col....) Gi*_ &
删除索引:drop index idxname Hxleh><c-
注:索引是不可更改的,想更改必须删除重新建。 ?I\,RiZkz^
9、说明:创建视图:create view viewname as select statement 8NTE`l=>/
删除视图:drop view viewname Qd>\{$N
10、说明:几个简单的基本的sql语句 /!`xqG#
选择:select * from table1 where 范围 JY~CMR5#.O
插入:insert into table1(field1,field2) values(value1,value2) s#(%u t
删除:delete from table1 where 范围 *M$'dLn
更新:update table1 set field1=value1 where 范围
MT$)A:"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8Dn~U:F/?
排序:select * from table1 order by field1,field2 [desc] 4=N(@mS
总数:select count as totalcount from table1 Yb1Q6[!
求和:select sum(field1) as sumvalue from table1 a>Zp?*9
平均:select avg(field1) as avgvalue from table1 'rA(+-.M;
最大:select max(field1) as maxvalue from table1 62K#rRS
最小:select min(field1) as minvalue from table1 t J&tNSjTi
qVjMflVoay
h
9}x6t,
>2X-98,
11、说明:几个高级查询运算词 IaU%L6Q]
aK
3'u
#7/39zTK
A: UNION 运算符 Ds#BfP7a
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。 ,J:Ro N_:
B: EXCEPT 运算符 F07X9s44E
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。 p./0N.
C: INTERSECT 运算符 aK7}}
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。 ~@#a*="
注:使用运算词的几个查询结果行必须是一致的。 +d(|Jid
12、说明:使用外连接 z\woTL6D]
A、left outer join: {Byh:-e<
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。 6RDy2JAOP
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 'S:$4j
B:right outer join: v *`M3jb
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 yqB!0)
<
C:full outer join: H8 xhE~'t
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 0sTR`Xk
|--Jd$ dj
qwO@>wQ}~
二、提升 N,3iSH=cN[
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) cv7:5P
法一:select * into b from a where 1<>1 P%N)]b<c*
法二:select top 0 * into b from a qB&Je$_uh
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ,i8%qm8
insert into b(a, b, c) select d,e,f from b; B&6lG!K'?
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) |68k9rq
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M}Xf<:g)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [AA}P/iW
4、说明:子查询(表名1:a 表名2:b) VKf&}u/
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) s[t<2)i
5、说明:显示文章、提交人和最后回复时间 v G9>e&Be
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7R# }AQ
6、说明:外连接查询(表名1:a 表名2:b) HxcL3Bh$~}
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l@ (:Q!Sk
7、说明:在线视图查询(表名1:a ) .t/@d(R
select * from (SELECT a,b,c FROM a) T where t.a > 1; JYv<QsD
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 PTqia!
select * from table1 where time between time1 and time2 _ElG&hyp
select a,b,c, from table1 where a not between 数值1 and 数值2 ]hoq!:>M1
9、说明:in 的使用方法 k+vfZ9bD(J
select * from table1 where a [not] in ('值1','值2','值4','值6') `csZ*$7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ga(k2Q;y
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *ZxurbX#
11、说明:四表联查问题: yc`*zLWh
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 ..... q6<P\CSHy<
12、说明:日程安排提前五分钟提醒 P,F
eF'J^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 -4P `:bF
13、说明:一条sql 语句搞定数据库分页 JbQY{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 x*=1C,C
14、说明:前10条记录 mCG&=Fx
select top 10 * form table1 where 范围 $L?KNXHAF!
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) E+#<WK-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) k%Vprc
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 CPMGsW^
(select a from tableA ) except (select a from tableB) except (select a from tableC) '4Fwh]Ee
17、说明:随机取出10条数据 lk[Y6yE
select top 10 * from tablename order by newid() ]vP}K
18、说明:随机选择记录 ~"NuYM#@
select newid() To5hVL<Ex"
19、说明:删除重复记录 Z*Gf`d:
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) z?( b|v
20、说明:列出数据库里所有的表名 | L1+7
select name from sysobjects where type='U' 5t"FNL
<(M
21、说明:列出表里的所有的 PB?2{Cj
select name from syscolumns where id=object_id('TableName') c&FOt
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 !a-B=pn!]
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type aB?usVoS
显示结果: aT(_c/t.
type vender pcs Rn]xxa'
电脑 A 1 qmt9J?$k
电脑 A 1 y@<2`h
光盘 B 2 YRFz]
光盘 A 2 w( _42)v]g
手机 B 3 -
l^3>!MAM
手机 C 3 9 <{C9
23、说明:初始化表table1
qLP/z
TRUNCATE TABLE table1 k~ByICE
24、说明:选择从10到15的记录 /zoy,t-i
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ??U/Qi180
\"Y,1in#
RjVmHhX
V)N{Fr)&
三、技巧 XmwAYf
1、1=1,1=2的使用,在SQL语句组合时用的较多 3 yy5 l!fv
"where 1=1" 是表示选择全部 "where 1=2"全部不选, D79:L:
如: <aDZ{T%
if @strWhere !='' G\TO]c
begin %^vT7c>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )>S,#_e*b
end %W)pZN}
else $(Mz@#%
begin F=
%A9b_a
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?Ve IlD
end GNe^~
我们可以直接写成 Y)+q[MZ R
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere XWyP'\
2、收缩数据库 \Z&Nd;o
--重建索引 l
$"hhI8
DBCC REINDEX $2?j2}M
DBCC INDEXDEFRAG IA({RE
--收缩数据和日志 mbGma
DBCC SHRINKDB kFV, Fg
DBCC SHRINKFILE XclTyUGoK+
3、压缩数据库 ~rJG4U
dbcc shrinkdatabase(dbname) |E.BGdS
4、转移数据库给新用户以已存在用户权限 [nP s
exec sp_change_users_login 'update_one','newname','oldname' 5<R m{
go [!-gb+L
5、检查备份集 G0Qw&
mqF
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 1/2cb-V
6、修复数据库 ,<r&]
eC
ALTER DATABASE [dvbbs] SET SINGLE_USER UNff&E-
GO <7`zc7c]#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK FutS
GO Mjy:k|aY"
ALTER DATABASE [dvbbs] SET MULTI_USER T?t/[iuHrj
GO .8Bo5)q$a-
7、日志清除 ?'9IgT[*
SET NOCOUNT ON d%"XsbO
DECLARE @LogicalFileName sysname, LzNfMvh
@MaxMinutes INT, .
yg#
@NewSize INT Cl]?qH*:
USE tablename -- 要操作的数据库名 d6YXITL)\>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2_+>a"8Y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. rUj\F9*5#
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]b!n ;{5
-- Setup / initialize -` U|5
DECLARE @OriginalSize int voRry6Q;
SELECT @OriginalSize = size )J}v.8
FROM sysfiles U5OX.0
WHERE name = @LogicalFileName 9ziFjP+1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <78|~SKAV
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _wS=*-fT
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $2?AJ/2r$b
FROM sysfiles 0!_?\)X
WHERE name = @LogicalFileName #e|o"R;/`
CREATE TABLE DummyTrans ;*M@LP{*L
(DummyColumn char (8000) not null) "J 1A9|
DECLARE @Counter INT, _>Raw
@StartTime DATETIME, h<`aL;.g
@TruncLog VARCHAR(255) Y(.e e%;,
SELECT @StartTime = GETDATE(), {;c'@U
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' N8{jvat
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7GYf#} N
EXEC (@TruncLog) cR/Nl pX
-- Wrap the log if necessary. jTvcKm|q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %+N]$Q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *;Mi/^pzK
AND (@OriginalSize * 8 /1024) > @NewSize |'nQvn:{
BEGIN -- Outer loop. <$0is:]
SELECT @Counter = 0 4a+gM._+O
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) b-sN#'TDg
BEGIN -- update dm4Q'u
INSERT DummyTrans VALUES ('Fill Log') ` 3qf}=Z`
DELETE DummyTrans <m]0!ii
SELECT @Counter = @Counter + 1 d-D,Gx]>$
END H@=oVyn/
EXEC (@TruncLog) ZH_$Q$9
END (?7=,A7^
SELECT 'Final Size of ' + db_name() + ' LOG is ' + d+D~NA[M
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + oLT#'42+H
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L7-BuW}&
FROM sysfiles
usB*Wn8
WHERE name = @LogicalFileName h*k V@Dc
DROP TABLE DummyTrans oS fr5
i
SET NOCOUNT OFF d_@
E4i
8、说明:更改某个表 Sfz1p
exec sp_changeobjectowner 'tablename','dbo' J rx^
9、存储更改全部表 )8@-
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch j Q5 F}
@OldOwner as NVARCHAR(128), mH&7{2r
@NewOwner as NVARCHAR(128) r ;RYGLx
AS AG@gOm
DECLARE @Name as NVARCHAR(128) c>_ti+
DECLARE @Owner as NVARCHAR(128) )S g6B;CJ
DECLARE @OwnerName as NVARCHAR(128) <l{oE?N
DECLARE curObject CURSOR FOR k&ci5MpN
select 'Name' = name, &zdS9e-fF
'Owner' = user_name(uid) u}[ a
from sysobjects q!y. cyL
where user_name(uid)=@OldOwner mgAjD.
order by name P}v
;d]
OPEN curObject u2 s
FETCH NEXT FROM curObject INTO @Name, @Owner ,t9EL 21
WHILE(@@FETCH_STATUS=0) yV(#z2|
BEGIN 79v +ze
if @Owner=@OldOwner ,|:.0g[n
begin qzUiBwUi@
set @OwnerName = @OldOwner + '.' + rtrim(@Name) y2jv84
M
exec sp_changeobjectowner @OwnerName, @NewOwner S hI1f
end .~f )4'T 9
-- select @name,@NewOwner,@OldOwner mr\,"S-`
FETCH NEXT FROM curObject INTO @Name, @Owner (p-q>@m
END Kjd3!%4mB
close curObject 0)ohab
deallocate curObject :y-;V
GO oMQ4q{&|
10、SQL SERVER中直接循环写入数据 z1J)./BO
declare @i int >1j#XA8
set @i=1 1=R$ RI
while @i<30 9zwD%3Ufn
begin 4X+xh|R:U
insert into test (userid) values(@i)
k pgA2u7
set @i=@i+1 n/_q
end .G{cx=;
小记存储过程中经常用到的本周,本月,本年函数 3K
&637
Dateadd(wk,datediff(wk,0,getdate()),-1) W{F)YyR{.
Dateadd(wk,datediff(wk,0,getdate()),6) ys9:";X;}
Dateadd(mm,datediff(mm,0,getdate()),0) >dl5^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |>;PV4])(
Dateadd(yy,datediff(yy,0,getdate()),0) Nk7y2[
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) I%5vI}
上面的SQL代码只是一个时间段 t*IePz] /
Dateadd(wk,datediff(wk,0,getdate()),-1) Lh[0B.g<
Dateadd(wk,datediff(wk,0,getdate()),6) {A0jkU
就是表示本周时间段. k&$ov
下面的SQL的条件部分,就是查询时间段在本周范围内的: d&+]@ Ii
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) z%8`F%2
而在存储过程中 t1w5U+z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) zZCl]cql
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) FK^xZ?G