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。 f}fM%0/5
n9#@
e}r
[P<oyd@#
一、基础 P\Ka'i
1、说明:创建数据库 Mqna0"IYx*
CREATE DATABASE database-name 'rSM6j
2、说明:删除数据库 F:n7yey
drop database dbname 3o1j l2n
3、说明:备份sql server !$O +M#
--- 创建 备份数据的 device
5!wa\)wY
USE master 1PWDK1GI8
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Z*k}I{0,-
--- 开始 备份 J~~WV<6
BACKUP DATABASE pubs TO testBack Alrk3I3{
4、说明:创建新表 zfS`@{;F`|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) *@D.=i>
根据已有的表创建新表: I!{5*~ 3
A:create table tab_new like tab_old (使用旧表创建新表) f\Qi()
B:create table tab_new as select col1,col2... from tab_old definition only Er{yQIi0L
5、说明:删除新表 \KTX{qI"f
drop table tabname oR5 'g7?
6、说明:增加一个列 FN G]
Alter table tabname add column col type um[.r,++
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。 w|N LK
7、说明:添加主键: Alter table tabname add primary key(col) 3t8VH`!mL{
说明:删除主键: Alter table tabname drop primary key(col) 1%>/%eyn5
8、说明:创建索引:create [unique] index idxname on tabname(col....) -&+[/
删除索引:drop index idxname VLR W,lR9O
注:索引是不可更改的,想更改必须删除重新建。 Wu:evaZ:i
9、说明:创建视图:create view viewname as select statement {`{U\w5Af
删除视图:drop view viewname aC;OFINK
10、说明:几个简单的基本的sql语句 y3d`$'7H>
选择:select * from table1 where 范围 emTqbO
插入:insert into table1(field1,field2) values(value1,value2) }e1f kjWk
删除:delete from table1 where 范围 Z[ys>\_To
更新:update table1 set field1=value1 where 范围 UZqr6A(/H
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! y<kW2<?
排序:select * from table1 order by field1,field2 [desc] oh|Q&R
总数:select count as totalcount from table1 'v?Z~"w=
求和:select sum(field1) as sumvalue from table1 x2l~aw#?
平均:select avg(field1) as avgvalue from table1 c!b4Y4eJ
最大:select max(field1) as maxvalue from table1 .|!Kv+yD
最小:select min(field1) as minvalue from table1 )[>{
Ie2
PyK)ks!6
>Ka}v:E
\:8
>@Q
11、说明:几个高级查询运算词 m#ID%[hg$
$vx]\`
^
T$!.
:v
A: UNION 运算符 d7A vx
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。 (V#5Cs,o:
B: EXCEPT 运算符
ym^
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。 SIVzc Hm
C: INTERSECT 运算符 b0t/~]9G
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。 Z!DGCw
注:使用运算词的几个查询结果行必须是一致的。 ).5$c0`U&
12、说明:使用外连接 54v}iG
A、left outer join: y$'(/iyz
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。 |BN^5mqP6
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 p4[cPt ~C
B:right outer join: Kx7s
d i
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。 2{(_{9<>z
C:full outer join: ]U82A**n
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。 wMr*D['" #
ve<D[jQsk
-uX): h!
二、提升 }Dp/K4
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |<gYzbq
法一:select * into b from a where 1<>1 741Sd8
法二:select top 0 * into b from a M]
7#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) /GRkQ",
insert into b(a, b, c) select d,e,f from b; WTbq)D(&[_
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) E&9BeU
a#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 az/NZlJhT
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. HW"@~-\
4、说明:子查询(表名1:a 表名2:b) +K {J*
n
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) {%gMA?b|"
5、说明:显示文章、提交人和最后回复时间 z&Cz!HrS
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @p"m{
6、说明:外连接查询(表名1:a 表名2:b) ^\KZE|^3@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c V^apDV\AV
7、说明:在线视图查询(表名1:a ) NSI$uS6
select * from (SELECT a,b,c FROM a) T where t.a > 1; H[S[ y
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 n
'gU
select * from table1 where time between time1 and time2 ir!/{IQx
select a,b,c, from table1 where a not between 数值1 and 数值2 p?PK8GL
9、说明:in 的使用方法 ~lib~Y'-
select * from table1 where a [not] in ('值1','值2','值4','值6') it77x3Mm
F
10、说明:两张关联表,删除主表中已经在副表中没有的信息 c&X2k\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Cl&YN}t5
11、说明:四表联查问题: 2!QQypQ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 05hjC
12、说明:日程安排提前五分钟提醒 LD/NMb
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lub_2Cb|j
13、说明:一条sql 语句搞定数据库分页 Q #IlUo
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ip8%9fG\>
14、说明:前10条记录 fRh}n ^X
select top 10 * form table1 where 范围 ZD ~ra7
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) y rH@:D/
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =Z}$X:
$
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 j]P'xrWl]8
(select a from tableA ) except (select a from tableB) except (select a from tableC) z[|2od
17、说明:随机取出10条数据 iC2``[m"
select top 10 * from tablename order by newid() ;S0Kf{DN2
18、说明:随机选择记录 /F@CrNFb(
select newid() %[B^b)2
19、说明:删除重复记录 }2%L
0
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) As{ "B
20、说明:列出数据库里所有的表名
z>lIZ}
select name from sysobjects where type='U' > zA*W<g
21、说明:列出表里的所有的 mUA!GzJ~u-
select name from syscolumns where id=object_id('TableName') M47t(9krV
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。 ?*LVn~y
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
w#}[=jy
显示结果: uo`zAKM&A
type vender pcs "rA-u)Te
电脑 A 1 i/|}#yw8A
电脑 A 1 n,D&pl9f
光盘 B 2 g^I?u$&E
光盘 A 2 "o)jB~:L
手机 B 3 Y#[xX2z9
手机 C 3 D,\hRQ
23、说明:初始化表table1 cXw8#M!
TRUNCATE TABLE table1 ghGpi U$
24、说明:选择从10到15的记录 pF/s5z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc q{Ao
j
P"[\p|[U
k@Qd:I;;
&ea6YQ
三、技巧 +N}yqgE
1、1=1,1=2的使用,在SQL语句组合时用的较多 %-fQ[@5
"where 1=1" 是表示选择全部 "where 1=2"全部不选, swKqsN.
如: 7?ICXhu9
if @strWhere !='' UMUG~P&@
begin TrPw*4h 9s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere WeZ?L|&%w0
end 2Q=I`H_
else `l2h65\
begin 18,;2Sr44
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b|pp}il
end u.ej<Lo
我们可以直接写成 !mH
!W5&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere uN&UYJ'B
2、收缩数据库 U0=: `G2l
--重建索引 qr4.s$VGs*
DBCC REINDEX 1R,SA:L$
DBCC INDEXDEFRAG IFsh"i
--收缩数据和日志 ;F|8#! (
DBCC SHRINKDB nvB<pSm
DBCC SHRINKFILE s+t[{i4|
3、压缩数据库 T*z*x=<5
dbcc shrinkdatabase(dbname) ka/>jV"
4、转移数据库给新用户以已存在用户权限 )LAG$Cn
exec sp_change_users_login 'update_one','newname','oldname' qh|fq
b
go 6t=)1T
5、检查备份集 .WLwAL
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &G!~@\tMg
6、修复数据库 NY?pvb
ALTER DATABASE [dvbbs] SET SINGLE_USER 'i<%kL@
GO &'k:?@J[
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,Cd4Q7T
GO O1Ynl`}
ALTER DATABASE [dvbbs] SET MULTI_USER }Gva=N:
GO +#L'gc
7、日志清除 8.HJoos
SET NOCOUNT ON J@A^k1B
DECLARE @LogicalFileName sysname, Qe =8x7oIP
@MaxMinutes INT, kho$At)V
@NewSize INT ~p?D[]h
USE tablename -- 要操作的数据库名 ^EJ]LNk}
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 vddl9"V)
@MaxMinutes = 10, -- Limit on time allowed to wrap log. C<#_1@^:8e
@NewSize = 1 -- 你想设定的日志文件的大小(M) h t3P@;
-- Setup / initialize =6a=`3r!I
DECLARE @OriginalSize int G/ H>M%M
SELECT @OriginalSize = size b,x$wP+
FROM sysfiles b#-=Dbe
WHERE name = @LogicalFileName ?)g [Xc;K
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <m/XGFc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + iD.p KG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' cx[[K.
FROM sysfiles i0u`J
WHERE name = @LogicalFileName RdB,;Um9f
CREATE TABLE DummyTrans fI,2l
(DummyColumn char (8000) not null) tn;Uaw
DECLARE @Counter INT, 8=)9ZjfD
@StartTime DATETIME, _\<TjGtG
@TruncLog VARCHAR(255) =om<* \vsO
SELECT @StartTime = GETDATE(), +&r=XJ5:`p
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' L|8&9F\
DBCC SHRINKFILE (@LogicalFileName, @NewSize) %%9T-+T
EXEC (@TruncLog) p7W9?b9
-- Wrap the log if necessary. 0ybMI+*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired BoXPX2:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =zR9^k
AND (@OriginalSize * 8 /1024) > @NewSize Yyw9IYB;
BEGIN -- Outer loop. liBFx6\"S
SELECT @Counter = 0 )-m/(-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,#bT
BEGIN -- update ^fV-m&F)K*
INSERT DummyTrans VALUES ('Fill Log') \E6 0
DELETE DummyTrans {]%7-4E
SELECT @Counter = @Counter + 1 -Un"z6*
END uqVarRi$
EXEC (@TruncLog) CDY3+!
END "pO**z$Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + cT@H49#uB
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + K#Xl)h}y7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Tv `&
FROM sysfiles .e4upTGU
WHERE name = @LogicalFileName +i[@+`
DROP TABLE DummyTrans v|dt[>G
SET NOCOUNT OFF ?w&?P}e +
8、说明:更改某个表 vXZ
)
exec sp_changeobjectowner 'tablename','dbo' \O]kf>nC
9、存储更改全部表 Qb7&S5m
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch RBHU5]5
@OldOwner as NVARCHAR(128), 0KZ$v/m
@NewOwner as NVARCHAR(128) dGUiMix{N
AS WHqw=!G
DECLARE @Name as NVARCHAR(128) ps^["3e
DECLARE @Owner as NVARCHAR(128) *uSlp_;kB
DECLARE @OwnerName as NVARCHAR(128) ZENblh8fs
DECLARE curObject CURSOR FOR +Ht(_+To1
select 'Name' = name, _;R#B`9Iu
'Owner' = user_name(uid) TrNh,5+b
from sysobjects a]J>2A@-I
where user_name(uid)=@OldOwner l
GJ N;G7
order by name h7 mk<
OPEN curObject 'J)9#
FETCH NEXT FROM curObject INTO @Name, @Owner ;I6C`N
WHILE(@@FETCH_STATUS=0) #%pY,AK:=
BEGIN E2tUL#
if @Owner=@OldOwner ]K+8f-
begin 3v&Shb?xb;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) oFhBq0@
exec sp_changeobjectowner @OwnerName, @NewOwner aWNjl
end S~W;Ld<>fB
-- select @name,@NewOwner,@OldOwner efuiFN;
FETCH NEXT FROM curObject INTO @Name, @Owner AF,;3G
END FxT]*mo
close curObject *\_>=sS x;
deallocate curObject $h}w:AV:
GO gB>AYL%o=
10、SQL SERVER中直接循环写入数据 iVo-z#
declare @i int eep/96G
?
set @i=1 %TO&
while @i<30 VF +g+~
begin UG vUU<N|N
insert into test (userid) values(@i) ,Xg^rV~]
set @i=@i+1 (,|eE)+
end Bc`L]<
小记存储过程中经常用到的本周,本月,本年函数 a'?LC)^
Dateadd(wk,datediff(wk,0,getdate()),-1) UR(i_T&w
Dateadd(wk,datediff(wk,0,getdate()),6) t0za%q!fK<
Dateadd(mm,datediff(mm,0,getdate()),0) <dAxB$16sT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7+Nl)d:CJ
Dateadd(yy,datediff(yy,0,getdate()),0) =BbXSwv'(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) VA`VDUG,
上面的SQL代码只是一个时间段 7jr+jNsowj
Dateadd(wk,datediff(wk,0,getdate()),-1) hu7oJ H
Dateadd(wk,datediff(wk,0,getdate()),6) 2@Q5Ta#h
就是表示本周时间段. ].Ra=^q
下面的SQL的条件部分,就是查询时间段在本周范围内的: .krEfY&
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) LoOw]@>
而在存储过程中 QIdml*Np?H
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $@w,9J\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^E)8Sb9t