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。 9J?G"JV?
}>:x
nD+vMG1~w
一、基础 ^J>jU`)CJ
1、说明:创建数据库 6#k
Ap+g7
CREATE DATABASE database-name 4565U
2、说明:删除数据库 swVq%]')"
drop database dbname 96Tc:#9i
3、说明:备份sql server Dc[Qu?]LM
--- 创建 备份数据的 device 4>gMe3]0
USE master WQ]~TGW
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9k^;]jE
--- 开始 备份 K`@GNT&
BACKUP DATABASE pubs TO testBack i%W,Y8\uf*
4、说明:创建新表 `C`_2y8
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h<9h2
根据已有的表创建新表: h(I~HZ[K&T
A:create table tab_new like tab_old (使用旧表创建新表) T]nZ3EZ
B:create table tab_new as select col1,col2... from tab_old definition only 3X{=*wvt
5、说明:删除新表 MQQ!@I`
drop table tabname [PrR30:
6、说明:增加一个列 Kk~0jP_ B9
Alter table tabname add column col type U"xI1fg%b
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。 Z8=4cWI~;
7、说明:添加主键: Alter table tabname add primary key(col) *4^!e/
说明:删除主键: Alter table tabname drop primary key(col) 6!i0ioZzi0
8、说明:创建索引:create [unique] index idxname on tabname(col....) g2hxWf"
删除索引:drop index idxname 2WIbu-"l
注:索引是不可更改的,想更改必须删除重新建。 `\&qk)ZP
9、说明:创建视图:create view viewname as select statement 9`)NFy?
删除视图:drop view viewname w<awCp
10、说明:几个简单的基本的sql语句 N2}].}
选择:select * from table1 where 范围 R9yK"
插入:insert into table1(field1,field2) values(value1,value2) }tU<RvT
删除:delete from table1 where 范围 %t\`20-1<
更新:update table1 set field1=value1 where 范围 VbtFM=Dg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #cQ[ vE)y
排序:select * from table1 order by field1,field2 [desc] ~2~KcgPsq
总数:select count as totalcount from table1 S[NV-)r=
求和:select sum(field1) as sumvalue from table1 oS$&jd
平均:select avg(field1) as avgvalue from table1 Z\{WBUR;4t
最大:select max(field1) as maxvalue from table1 ^n<p#0)+a
最小:select min(field1) as minvalue from table1 ];1z%.
e@L'H)w,
h2KXW}y"4
11
.RG
*
11、说明:几个高级查询运算词 HqU"iY>b
3;j?i<kM
{61NLF\0H
A: UNION 运算符 +6f5uMKUvs
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ''wWw(2O
B: EXCEPT 运算符 FI~)ZhE)]
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 QHsS|\u
C: INTERSECT 运算符 jjz<V(Sk
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 RH. oo&
注:使用运算词的几个查询结果行必须是一致的。
mYb8
12、说明:使用外连接 jo<[|ZD
A、left outer join: e9q/[xMi
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 iYv6B6o/99
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c P7E}^y`e
B:right outer join: slHlfWHq
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 sj`9O- ?49
C:full outer join: (>>pla^
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 .dp~%!"Sn,
;oULtQ
ix]3t^
二、提升 :M ix*NCf
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) r[M]2h
法一:select * into b from a where 1<>1 :H\6wJ
法二:select top 0 * into b from a z0HCmj9T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) mw`%xID*
insert into b(a, b, c) select d,e,f from b; ~@bCSOIy
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ?i(Tc!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 pp#Kb 2*
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. GwwxSB&y
4、说明:子查询(表名1:a 表名2:b) 4I^6[{_
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) _e8@y{/~Fd
5、说明:显示文章、提交人和最后回复时间 ?YgK]IxD
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4\2p8__
6、说明:外连接查询(表名1:a 表名2:b) +]CKu$,8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c IVkKmO(qO
7、说明:在线视图查询(表名1:a ) eJ%~6c`@!
select * from (SELECT a,b,c FROM a) T where t.a > 1; $z{HNY*2
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 QD<^VY6
select * from table1 where time between time1 and time2 !V@Y \M
d
select a,b,c, from table1 where a not between 数值1 and 数值2 cWp
n/.a
9、说明:in 的使用方法 Iu(T@",Q#
select * from table1 where a [not] in ('值1','值2','值4','值6') N!"GwH
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >H5BY9]I
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) v>)[NAY9
11、说明:四表联查问题: Y#{KGVT<
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ',6QL4qV/
12、说明:日程安排提前五分钟提醒
M5exo
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 =t&B8+6
13、说明:一条sql 语句搞定数据库分页 *xU^e`P
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 n1uJQt
14、说明:前10条记录 v2EM| Q xp
select top 10 * form table1 where 范围 w>H!H6Q
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 6l [TQ
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) lbT<HWzNH
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 %MbjKw
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,$vc*}yI0
17、说明:随机取出10条数据 4VaUa8 D
select top 10 * from tablename order by newid() x;Dr40wD@y
18、说明:随机选择记录 k%:]PQjYT
select newid() #&r^~>,#L-
19、说明:删除重复记录 Q-O:L
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +VDl"Hx
20、说明:列出数据库里所有的表名 9qwVBu ;
select name from sysobjects where type='U' -1S+fUkiK/
21、说明:列出表里的所有的 wXXv0OzK
select name from syscolumns where id=object_id('TableName') BIbcm,YQ
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。 uTP=kgYqJ
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 s4MP!n?gB
显示结果: ^bL.|vB
type vender pcs eiP>?8
电脑 A 1 kc|`VB8L
电脑 A 1 pwd7I
光盘 B 2 wm*`
光盘 A 2 kZ`60X%wE
手机 B 3 b
|m$ W
手机 C 3 |KU>+4=
@
23、说明:初始化表table1 }[D~#Z!k
TRUNCATE TABLE table1 TDtk'=;
24、说明:选择从10到15的记录 z ;y22
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc yn!LJT[~2
c
!P9`l~MQ
%>xW_5;Z
.b N0!
三、技巧 6$)Yqg`X
1、1=1,1=2的使用,在SQL语句组合时用的较多 L V33vy
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W|D'S}J
如: 0[PPVr:
if @strWhere !='' JYm@Llf)$
begin XuR!9x^5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere jc Ie<i;
end xC<OFpI\
else NO`a2HR$
begin ]wa?~;1^&
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8-juzL}
end Jev@IORN\
我们可以直接写成 ?h
K+h .{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 39"8Nq|e
2、收缩数据库 \+Qx}bS{
--重建索引 j*W]^uT,
DBCC REINDEX ~O@V;y
DBCC INDEXDEFRAG o~<fw]y
--收缩数据和日志 Rc?wIL)
DBCC SHRINKDB G*ym[
DBCC SHRINKFILE pgU54Ef
3、压缩数据库 nN@8vivP%
dbcc shrinkdatabase(dbname) )u\"xxcV
4、转移数据库给新用户以已存在用户权限 HX+'{zm]
exec sp_change_users_login 'update_one','newname','oldname' D9#e2ex]
go <po(7XB
5、检查备份集 )]>=Uo
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' A3'i
-
6、修复数据库 K{M_ 4'\
ALTER DATABASE [dvbbs] SET SINGLE_USER @] )a
GO "-v9V7KCM
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &giJO-^
f
GO $vGl Z<3g
ALTER DATABASE [dvbbs] SET MULTI_USER x3wyIio*
GO SGNi~o
7、日志清除 qUpMq:Uw
SET NOCOUNT ON
@tDVW*!
DECLARE @LogicalFileName sysname, z?j~ 2K<4
@MaxMinutes INT, I|Z5*iXqCm
@NewSize INT fB
USE tablename -- 要操作的数据库名 (zJ
TBI'
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !R{L`T0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ']Y:f)i#
@NewSize = 1 -- 你想设定的日志文件的大小(M) Z?"Pkc.Ei
-- Setup / initialize 3gv>AgG
DECLARE @OriginalSize int UvQxtT]
SELECT @OriginalSize = size 7OC,KgJ3
FROM sysfiles ; M"hX
WHERE name = @LogicalFileName ;EFs2-{K
SELECT 'Original Size of ' + db_name() + ' LOG is ' + TrkoLJmB
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `Ph4!-6#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' aWe
H,A%
FROM sysfiles {r'#(\
WHERE name = @LogicalFileName /Pg66H#RUf
CREATE TABLE DummyTrans 2{+\\.4Evk
(DummyColumn char (8000) not null) $`l- cSH;
DECLARE @Counter INT, Q$kSK+ q!
@StartTime DATETIME, tTWYlbDFN
@TruncLog VARCHAR(255) VEb}KFyP
SELECT @StartTime = GETDATE(), CCl*v
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?F?!QrL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ua4QtDSs
EXEC (@TruncLog) Q
CfA3*
-- Wrap the log if necessary. $G*$j!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired rf)\:75
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^>9M2O['!s
AND (@OriginalSize * 8 /1024) > @NewSize n]9y Cr
BEGIN -- Outer loop. {T:2+iS9:
SELECT @Counter = 0 ]lZ!en
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 7|,5;
BEGIN -- update InPq1AH
INSERT DummyTrans VALUES ('Fill Log') UnW,|n8
DELETE DummyTrans R['qBHQ?
SELECT @Counter = @Counter + 1 +(cs,?`\
END V\ARe=IWM
EXEC (@TruncLog) 8
A%)m
END Fo;xA
SELECT 'Final Size of ' + db_name() + ' LOG is ' + j24BB}mBB
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
Vs{|:L+
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5Z`f)qE
FROM sysfiles 5G\vV]RR&
WHERE name = @LogicalFileName /JR*X!&"
DROP TABLE DummyTrans pw- C=MY]
SET NOCOUNT OFF n~K_|
8、说明:更改某个表 Q4c>gds`
exec sp_changeobjectowner 'tablename','dbo' s{IycTbz
9、存储更改全部表 )5&w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch s|EP/=9i
@OldOwner as NVARCHAR(128), EkOBI[`
@NewOwner as NVARCHAR(128) p(U'c}@2
AS nBGk %NM 8
DECLARE @Name as NVARCHAR(128) )W*S6}A
DECLARE @Owner as NVARCHAR(128) 8#7z5:_
DECLARE @OwnerName as NVARCHAR(128) Eer rIV
DECLARE curObject CURSOR FOR v9M;W+J
select 'Name' = name, 5^f>L2
'Owner' = user_name(uid) #{ `(;83
from sysobjects 7*@qd&
where user_name(uid)=@OldOwner #G9S[J=xe
order by name (hd2&mSy
OPEN curObject QabF(}61
FETCH NEXT FROM curObject INTO @Name, @Owner fS!%qr
WHILE(@@FETCH_STATUS=0) #\t?`\L3
BEGIN RUO,tB|(_;
if @Owner=@OldOwner 6I_W4`<VeZ
begin dk{yx(Ty
set @OwnerName = @OldOwner + '.' + rtrim(@Name) (kb^=kw#0
exec sp_changeobjectowner @OwnerName, @NewOwner `;QpPSw +
end ~poy`h'
-- select @name,@NewOwner,@OldOwner Ov?k4kJ
FETCH NEXT FROM curObject INTO @Name, @Owner mQJRq??P
END #XC\=pZX
close curObject ">CjnF2>R
deallocate curObject qjUQ2d
GO +s1mm c
10、SQL SERVER中直接循环写入数据 Z$HYXm
declare @i int Q> @0'y=s
set @i=1 ;t"#7\
while @i<30 in#g
begin v0=^Hym
insert into test (userid) values(@i) *PZN Z{|m
set @i=@i+1 ^U:pv0Qz
end _~5{l_v|I
小记存储过程中经常用到的本周,本月,本年函数 jk 9K>4W
Dateadd(wk,datediff(wk,0,getdate()),-1) B{c,/{ =O
Dateadd(wk,datediff(wk,0,getdate()),6) rf]]I#C7
Dateadd(mm,datediff(mm,0,getdate()),0) oD~VK,.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >,32~C
Dateadd(yy,datediff(yy,0,getdate()),0) (AXSQI~y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) I&R4.;LW
上面的SQL代码只是一个时间段 m:Z=: -x
Dateadd(wk,datediff(wk,0,getdate()),-1) yWt87+%T
Dateadd(wk,datediff(wk,0,getdate()),6) -i?!em'J
就是表示本周时间段. SaQ_%-p
下面的SQL的条件部分,就是查询时间段在本周范围内的: vPSH
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) JBi<TDm/
而在存储过程中 ,$W7Q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )Hl;9
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (j}"1