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。 +:KZEFY?<
~;"eNg{T
LO`0^r
一、基础 uyj!$}4
1、说明:创建数据库 '@n"'vks(\
CREATE DATABASE database-name &h5Vhzq(<
2、说明:删除数据库 6{2y$'m8
drop database dbname x ytrd.
3、说明:备份sql server FnGKt\
--- 创建 备份数据的 device
b_x!m{
USE master 1iT_mtXK$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' j+jC
J<
--- 开始 备份 j*%#~UFw
BACKUP DATABASE pubs TO testBack ndSu-8?L
4、说明:创建新表 E>fY,*0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) mF6-f#t>H+
根据已有的表创建新表: 6uRE9h|
A:create table tab_new like tab_old (使用旧表创建新表) xdSMYH{2A
B:create table tab_new as select col1,col2... from tab_old definition only HSruue8
5、说明:删除新表 RoqkT|#$
drop table tabname a*M|_&MH*
6、说明:增加一个列 !yNU-/K
Alter table tabname add column col type (hc!!:N~q
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。 1mFH7A($
7、说明:添加主键: Alter table tabname add primary key(col) '(]Wtx%9"
说明:删除主键: Alter table tabname drop primary key(col) Wv4$Lgr
8、说明:创建索引:create [unique] index idxname on tabname(col....) NEBhVh
删除索引:drop index idxname Qf:e;1F!
注:索引是不可更改的,想更改必须删除重新建。 ][
$UN
9、说明:创建视图:create view viewname as select statement S>lP?2J
删除视图:drop view viewname e~vO
10、说明:几个简单的基本的sql语句 <&eJIz=
选择:select * from table1 where 范围 q;K]NP-_p
插入:insert into table1(field1,field2) values(value1,value2) @&*TGU
删除:delete from table1 where 范围 R@\fqNq
更新:update table1 set field1=value1 where 范围 _S_,rTf&
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F8%^Ed~@
排序:select * from table1 order by field1,field2 [desc] 4MC]s~n
总数:select count as totalcount from table1 6~dAK3v5
求和:select sum(field1) as sumvalue from table1 xW"O|x$6
平均:select avg(field1) as avgvalue from table1 S^s-md>
最大:select max(field1) as maxvalue from table1 Ar%*NxX
最小:select min(field1) as minvalue from table1 _`2%)#^o
'(K4@[3t
dsIbr"m
5<Kt"5Z%7
11、说明:几个高级查询运算词 B)q }]Qn
2a@X-Di
iwnGWGcuS
A: UNION 运算符 r\m{;Z#LJm
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,2AulX1
B: EXCEPT 运算符 ~<1s[Hu
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 w1<pQ[A
C: INTERSECT 运算符 P2'c{],3V
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 L=(-BYS
注:使用运算词的几个查询结果行必须是一致的。 )Kx.v'
12、说明:使用外连接 8GkWo8rPk
A、left outer join: AQ-PHv
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 \>$zxC_
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 ?y|&Mz'XJ(
B:right outer join: Zbo4{.#
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。 RFw0u 0Nrz
C:full outer join: 7(/yyZQnZ
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}~s"Sz
Od.@G ~
+}jzge"
二、提升 -zECxHjx
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) CH7a4qL`
法一:select * into b from a where 1<>1 AMrYT+1
法二:select top 0 * into b from a $NCvF'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) /l`zZ>
insert into b(a, b, c) select d,e,f from b; -w+.'
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) J>X@g;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 0LW3VfvToN
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t__f=QB/
4、说明:子查询(表名1:a 表名2:b) 8jCho
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3)
qiOtbH=
5、说明:显示文章、提交人和最后回复时间
Y*xgY*K
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b >V.?XZ nt
6、说明:外连接查询(表名1:a 表名2:b) 33%hZ`/>
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c GUL~k@:_k
7、说明:在线视图查询(表名1:a ) WD4"ft
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^Zl[#:EFP
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 /CALXwL
select * from table1 where time between time1 and time2 YusmMsN?
select a,b,c, from table1 where a not between 数值1 and 数值2 PE{<'K\g
9、说明:in 的使用方法 1
F:bExQ
select * from table1 where a [not] in ('值1','值2','值4','值6') +1#;s!e
10、说明:两张关联表,删除主表中已经在副表中没有的信息 K^x{rn.Zf
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Bc!<!
11、说明:四表联查问题: +At[[
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *6JA&zj0B
12、说明:日程安排提前五分钟提醒 3MX#}_7A
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Z +/3rd
13、说明:一条sql 语句搞定数据库分页 cRI2$|
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 jl59;.P
14、说明:前10条记录 S^R dj ]
select top 10 * form table1 where 范围 @ws&W=NQ
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.) 3ZT3I1/D
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) e=XP4h
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 e&ti(Q=
(select a from tableA ) except (select a from tableB) except (select a from tableC) cvw17j
17、说明:随机取出10条数据 &NF$_*\E
select top 10 * from tablename order by newid() z*HM_u
18、说明:随机选择记录 )4fQ~)
select newid() b!t[PShw^
19、说明:删除重复记录 7 @\i5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) p` ~=v4;b
20、说明:列出数据库里所有的表名 *X3wf`C?
select name from sysobjects where type='U' 7OLHY t9
21、说明:列出表里的所有的 w[a(I}x
select name from syscolumns where id=object_id('TableName') 5_A*IC]
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 NxJnU<g-
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type AQ
FnS&Y
显示结果: q%d,E1
type vender pcs ebEI%8p g
电脑 A 1 "E<+idoz
电脑 A 1 v2gk1a&
光盘 B 2 !4v>|t q!
光盘 A 2 .{eMN[ n@
手机 B 3 ]@y%j'e
手机 C 3 3L2NenJB
23、说明:初始化表table1 Y'1
KH}sH
TRUNCATE TABLE table1 {'alA
24、说明:选择从10到15的记录 ftmPdha%+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc bOU"s>?
F<h+d917
{$t*XTY6R
%1
RWF6
三、技巧 [PXq<ST
1、1=1,1=2的使用,在SQL语句组合时用的较多 |WUM=g7PC
"where 1=1" 是表示选择全部 "where 1=2"全部不选, OL_#Uu
如: B0 A`@9
if @strWhere !='' 7"Nda3
begin 4'3;{k$z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0"j:-1
end %4`
U' j
else O\uIIuy
begin tvno3"
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 3AENY@*
end PcbhylKd
我们可以直接写成 +*Wlj8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere lA4-ZQ2Zp[
2、收缩数据库 6
o
--重建索引 W.s8!KH:
DBCC REINDEX erv94acq
DBCC INDEXDEFRAG nN.Gn+Cl
--收缩数据和日志 Yt =)=n
DBCC SHRINKDB Bi9Q8#lh
DBCC SHRINKFILE ObZhQ.&
3、压缩数据库 RFsUb:%V7-
dbcc shrinkdatabase(dbname) qh W]Wd"g
4、转移数据库给新用户以已存在用户权限 \{Q_\s&)
exec sp_change_users_login 'update_one','newname','oldname' {o^tSEN!-
go H9'psv
5、检查备份集 c?<)!9:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -Sh&x
6、修复数据库 2\&3x}@
ALTER DATABASE [dvbbs] SET SINGLE_USER 3O4,LXdA
GO :G98uX t
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Fnk@)1
GO QSzht$8
ALTER DATABASE [dvbbs] SET MULTI_USER 3st?6?7|
GO gP|-A`y
7、日志清除 ,gpEXUp\
SET NOCOUNT ON )sQ/$gJ
DECLARE @LogicalFileName sysname, RIUJX{?
@MaxMinutes INT, myVa5m!7Q
@NewSize INT
{d#sZT
USE tablename -- 要操作的数据库名 I%:?f{\
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4dN <B U
@MaxMinutes = 10, -- Limit on time allowed to wrap log. T)<^S(57
@NewSize = 1 -- 你想设定的日志文件的大小(M) 96;5
-- Setup / initialize :!cK?H$+
DECLARE @OriginalSize int A[@koLCL
SELECT @OriginalSize = size fp(zd;BSQ
FROM sysfiles $;(@0UDE
WHERE name = @LogicalFileName H_XspiB@
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %H{;wVjK
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + PepR]ym
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g/68&
M
FROM sysfiles |Wa.W0A
WHERE name = @LogicalFileName 'Qg!ww7O
CREATE TABLE DummyTrans WqM| nX
(DummyColumn char (8000) not null) i/C%
1<
DECLARE @Counter INT, cGm?F,/`
@StartTime DATETIME, )RTWt`
@TruncLog VARCHAR(255) &ID! lEd
SELECT @StartTime = GETDATE(), _pb*kJ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "uL~D5!f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )w<Z4_!N4s
EXEC (@TruncLog) 9iJ$M!
-- Wrap the log if necessary. wA7\K~fHV
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired # X1a v
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7.
$wK.
AND (@OriginalSize * 8 /1024) > @NewSize 7*M-?
BEGIN -- Outer loop. _UZPQ[
SELECT @Counter = 0 RcJtVOrd
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) a {x3FQ
BEGIN -- update ?zC{T*a
INSERT DummyTrans VALUES ('Fill Log') ,)dlL tUm
DELETE DummyTrans /zXOtaG
SELECT @Counter = @Counter + 1 IIT[^_g
END 6`6 / 2C$%
EXEC (@TruncLog) iOZ#}"
END i?b9zn
SELECT 'Final Size of ' + db_name() + ' LOG is ' + iF
+@aA
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + }=\?]9`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5|r*,!CF
FROM sysfiles 21Dc.t{
WHERE name = @LogicalFileName "l-#v|
54
DROP TABLE DummyTrans )HI\T];
SET NOCOUNT OFF 1MO-60
8、说明:更改某个表 2<!IYEyT
exec sp_changeobjectowner 'tablename','dbo' DOGGQ$0
9、存储更改全部表 {9{X\|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch co\Il]`R/
@OldOwner as NVARCHAR(128), Gt?l 2s
@NewOwner as NVARCHAR(128) 32HF&P+0%
AS .`_iWfK
DECLARE @Name as NVARCHAR(128) .vy@uT,
DECLARE @Owner as NVARCHAR(128) 8!.V`|@lt
DECLARE @OwnerName as NVARCHAR(128) !x
~s`z
DECLARE curObject CURSOR FOR "P|n'Mx
select 'Name' = name, M?My+o T
'Owner' = user_name(uid) 2z#S|$
from sysobjects .hG*mXw>
where user_name(uid)=@OldOwner )qMbk7:v\
order by name l(87s^_
OPEN curObject ?aWVfX!+G5
FETCH NEXT FROM curObject INTO @Name, @Owner EFx>Hu/[G
WHILE(@@FETCH_STATUS=0) {Ak
4G L
BEGIN )=iv3nF?6N
if @Owner=@OldOwner :Cx|(+T
begin }@t"B9D
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1|w@f&W"
exec sp_changeobjectowner @OwnerName, @NewOwner k]$oir
end +ansN~3
-- select @name,@NewOwner,@OldOwner =+mb@#="m
FETCH NEXT FROM curObject INTO @Name, @Owner }
)Lz%Z
END 7$g$p&,VX
close curObject ,YvOk|@R
deallocate curObject ;ltk}hJ]
GO ff R%@
10、SQL SERVER中直接循环写入数据 O<V 4j,
declare @i int %1jcY0zEQ
set @i=1 >P@VD"U
while @i<30 T^`; wD
begin li\=mH,Wr
insert into test (userid) values(@i) lqMr@
:t
set @i=@i+1 6i+,/vr
end (57!{[J
小记存储过程中经常用到的本周,本月,本年函数 o<3$|`S&
Dateadd(wk,datediff(wk,0,getdate()),-1) .1;UEb|T
Dateadd(wk,datediff(wk,0,getdate()),6) ;>5`Y8s6
Dateadd(mm,datediff(mm,0,getdate()),0) MIr+4L
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ~AYl eM
Dateadd(yy,datediff(yy,0,getdate()),0) *-5N0K<kQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Q0K$ZWM`7
上面的SQL代码只是一个时间段 .?QYqGcG
Dateadd(wk,datediff(wk,0,getdate()),-1) N2'aC}
I
Dateadd(wk,datediff(wk,0,getdate()),6) %>=6v}f,+
就是表示本周时间段. YK6'/2!
下面的SQL的条件部分,就是查询时间段在本周范围内的: $qYP|W
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M$Z2"F;
而在存储过程中 t>?tWSNf
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *n EkbI/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4LB8p7$|a3