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。 #]i*u1
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一、基础 r>S?,qr
1、说明:创建数据库 /i$
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CREATE DATABASE database-name d_*'5Eia6
2、说明:删除数据库 mvI[=e*
drop database dbname TdI5{?sW
3、说明:备份sql server R74kt36M
--- 创建 备份数据的 device ~#dNGWwG
USE master FFl[[(`%D
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' o~,dkV
--- 开始 备份 <8p53*a
BACKUP DATABASE pubs TO testBack a&~d,vC
4、说明:创建新表 QF(.fq8, U
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [y|"iSD
根据已有的表创建新表: |jV>
A:create table tab_new like tab_old (使用旧表创建新表) 0&Q-y&$7
B:create table tab_new as select col1,col2... from tab_old definition only :3$WY<
5、说明:删除新表 c4oQ4
drop table tabname ]'=]=o~4
6、说明:增加一个列 j`A%(()d
Alter table tabname add column col type }<o.VY&;.
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。 m(E-?VMHo
7、说明:添加主键: Alter table tabname add primary key(col) W~+
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说明:删除主键: Alter table tabname drop primary key(col) ^ElUU ?rX
8、说明:创建索引:create [unique] index idxname on tabname(col....) 2e zQX2q
删除索引:drop index idxname );V6YE
注:索引是不可更改的,想更改必须删除重新建。 cj@Ygc)n
9、说明:创建视图:create view viewname as select statement ~U#afGH$
删除视图:drop view viewname '5.n28W>
10、说明:几个简单的基本的sql语句 mL`,v
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选择:select * from table1 where 范围 q'77BRD3
插入:insert into table1(field1,field2) values(value1,value2) f8kPbpV,
删除:delete from table1 where 范围 W}bed],l
更新:update table1 set field1=value1 where 范围 5\}A8Ng
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .t''(0_kC
排序:select * from table1 order by field1,field2 [desc] I.TdYSB
总数:select count as totalcount from table1 N"/jn_>+j
求和:select sum(field1) as sumvalue from table1 wl #Bv,xf
平均:select avg(field1) as avgvalue from table1 [ ps5;
最大:select max(field1) as maxvalue from table1 R)d1]k8
最小:select min(field1) as minvalue from table1 DVt;I$
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11、说明:几个高级查询运算词 Y&KI/]ly,L
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A: UNION 运算符 :@{(^}N8u
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。 /)Bk
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B: EXCEPT 运算符 R!b<Sg
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。 |uId:^{
C: INTERSECT 运算符 % 1ZJi}~
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。 13wO6tS
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注:使用运算词的几个查询结果行必须是一致的。 /"?yB$s
12、说明:使用外连接 F|3Te?_
A、left outer join: Gs;wx_k^
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 G#-t&gO3
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c OAO|HH
B:right outer join: {J;[
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 P_6oMR
C:full outer join: :UM>`Y
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 P*Va<'{:{
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二、提升 ;"46H'>!
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) {Qbg'|HO=l
法一:select * into b from a where 1<>1 F
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法二:select top 0 * into b from a |N, KA|Gdq
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) H<41H;m
insert into b(a, b, c) select d,e,f from b; =n.d'
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) z5`AJrj%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3y?I^ .B
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .Qk T-12
4、说明:子查询(表名1:a 表名2:b) koDIxj'%X
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) F!.Z@y P
5、说明:显示文章、提交人和最后回复时间 E{x<P0 ;
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b OQ>8Q`
6、说明:外连接查询(表名1:a 表名2:b) [y$P'Y
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+gS%o$
7、说明:在线视图查询(表名1:a ) 4.Luy
select * from (SELECT a,b,c FROM a) T where t.a > 1; dC+WII`V
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 D! TFb E
select * from table1 where time between time1 and time2 $Y'}wB{pc
select a,b,c, from table1 where a not between 数值1 and 数值2 E;m]RtvH
9、说明:in 的使用方法 \Gm$hTvB&
select * from table1 where a [not] in ('值1','值2','值4','值6') lz1RAp0R"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 SQ&nQzL
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) fNR2(8;}
11、说明:四表联查问题: 5B6twn~[
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 ..... V$wW?+V
12、说明:日程安排提前五分钟提醒 IBfLb(I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _v=S4A#tF
13、说明:一条sql 语句搞定数据库分页 RE)!b
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 I_hus
14、说明:前10条记录 lGoP(ki
select top 10 * form table1 where 范围 2IMU &
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) !@>_5p>q*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Yf1&"WW4
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 c,@&Z#IZ`
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7Yv1et
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17、说明:随机取出10条数据 >}~\*Y\8@
select top 10 * from tablename order by newid() ]'IZ bx:
18、说明:随机选择记录 QjT$.pUd
select newid() au=A+
19、说明:删除重复记录 }+mIP:T
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) b0VEMu81k
20、说明:列出数据库里所有的表名 6ijL+5
select name from sysobjects where type='U' 9j94]w2v
21、说明:列出表里的所有的 +"mS<
select name from syscolumns where id=object_id('TableName') ,gO}H)v]t
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。 F#b^l}
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 5r2A^<)
显示结果: )wZ;}O
type vender pcs ~Un+Zs%24
电脑 A 1 \p4>onGI
电脑 A 1 |.#G G7F^S
光盘 B 2 Fal##6B
光盘 A 2 nu(;yIRP
手机 B 3 yN@3uYBF
手机 C 3 P^3`znq{
23、说明:初始化表table1 % _.kd"
TRUNCATE TABLE table1 yf4I<v$y
24、说明:选择从10到15的记录 \=1$$EDS9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc cy-o@U"s8
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三、技巧 QjlQsN!
1、1=1,1=2的使用,在SQL语句组合时用的较多 vZiuElxKi
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n 9>**&5L
如: *SK`&V
if @strWhere !='' V|{\8&2
begin Xi~7pH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mOC<a7#
end <da-iY\5
else &wa2MNCG8
begin En9>onJ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' |NdWx1
end sRI0;
我们可以直接写成 h`n)
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere $2E&~W %
2、收缩数据库 a.z)m}+
--重建索引 Z35(f0b
DBCC REINDEX [C#H _y(
DBCC INDEXDEFRAG d iWi0@
--收缩数据和日志 -Hh.8(!XoO
DBCC SHRINKDB aGAeRF
DBCC SHRINKFILE ge4Qa K
3、压缩数据库 im3BQIPR
dbcc shrinkdatabase(dbname) j4:Xel/
4、转移数据库给新用户以已存在用户权限 &J\<"3
exec sp_change_users_login 'update_one','newname','oldname' oLS/
go 50CjH"3PZ`
5、检查备份集 gX|We}H
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' K`0'2
6、修复数据库 P:>]a$Is
ALTER DATABASE [dvbbs] SET SINGLE_USER *{("T
GO MW2{w<-]7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK h e[2,
GO sOO_J!bblP
ALTER DATABASE [dvbbs] SET MULTI_USER >}E
GO (nwp s
7、日志清除 5uX-onP\[
SET NOCOUNT ON u[HamGxx$u
DECLARE @LogicalFileName sysname, 90 >V he
@MaxMinutes INT, Bm5\*Xd1(
@NewSize INT []$L"?]0uk
USE tablename -- 要操作的数据库名 CB0p2WS_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5.LfN{gE)
@MaxMinutes = 10, -- Limit on time allowed to wrap log. h0?w V5H
@NewSize = 1 -- 你想设定的日志文件的大小(M) h])oo:u'/Q
-- Setup / initialize d2?#&d'aq
DECLARE @OriginalSize int NRT@"3,1YP
SELECT @OriginalSize = size >qVSepK3
FROM sysfiles }tO>&$
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WHERE name = @LogicalFileName CiV^bYi
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^fQa whub
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + W9QVfe#s
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' p^1~o/
FROM sysfiles }]Nt:_UCX
WHERE name = @LogicalFileName J|w%n5Y
CREATE TABLE DummyTrans \YSprXe
(DummyColumn char (8000) not null) hEFOT]P4
DECLARE @Counter INT, #;=sJ[m4
@StartTime DATETIME, c#f@v45
@TruncLog VARCHAR(255) <.2jQ#So
SELECT @StartTime = GETDATE(), XE]"RD<z
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' e{H(
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0g;)je2_2?
EXEC (@TruncLog) lL&U
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-- Wrap the log if necessary. 4Y{;%;-i
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired dZo x;_b
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1xr2x;
AND (@OriginalSize * 8 /1024) > @NewSize EywBT
BEGIN -- Outer loop. .K]Uk/W
SELECT @Counter = 0 3~{0X-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) kS?CKd9by
BEGIN -- update W4bN']?
INSERT DummyTrans VALUES ('Fill Log') xS:n
DELETE DummyTrans ;XQ27,K&
SELECT @Counter = @Counter + 1 GKKDO+A=!
END @j"6f|d
EXEC (@TruncLog) +* j8[sz
END '\GU(j
SELECT 'Final Size of ' + db_name() + ' LOG is ' + JL>frS3M
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + O~v~s
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <k0/O
FROM sysfiles M ziOpraj
WHERE name = @LogicalFileName z4~p(tl
DROP TABLE DummyTrans 4U16'd
SET NOCOUNT OFF /\;m/cwrl"
8、说明:更改某个表 #WJ*)$A@&
exec sp_changeobjectowner 'tablename','dbo' Pf/8tXs}
9、存储更改全部表 O"/Sv'|H#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch t-5Y,}j
@OldOwner as NVARCHAR(128), &r,)4q+
@NewOwner as NVARCHAR(128) $4}G
AS "$aoI Xv
DECLARE @Name as NVARCHAR(128)
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DECLARE @Owner as NVARCHAR(128) u:f.;?
DECLARE @OwnerName as NVARCHAR(128) hu1ZckIw?
DECLARE curObject CURSOR FOR "Zx<hL*
select 'Name' = name, ,<'>jaC
'Owner' = user_name(uid) #@xB ?u-0q
from sysobjects qGX#(,E9;
where user_name(uid)=@OldOwner J3(E{w8Q
order by name #vhN$H :&q
OPEN curObject ?3 k_YN"
FETCH NEXT FROM curObject INTO @Name, @Owner s2GF*{
WHILE(@@FETCH_STATUS=0) !%D';wQ,/
BEGIN 0:>hK\F#
if @Owner=@OldOwner @g4o8nH}
begin I{r*Y9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) C\aHr!
exec sp_changeobjectowner @OwnerName, @NewOwner _Gf-s51s
end |
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-- select @name,@NewOwner,@OldOwner &oq0XV.M^
FETCH NEXT FROM curObject INTO @Name, @Owner .}v" `>x
END CoNaGb
close curObject ux)*B}/xh
deallocate curObject LiV&47e*>
GO ^/#G,MxNy
10、SQL SERVER中直接循环写入数据
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declare @i int 7U_ob"`JV
set @i=1 FRZ]E)9Z]b
while @i<30 iiMS3ueF
begin 8K?}!$fz
insert into test (userid) values(@i) c/A?-9
set @i=@i+1 gmbRH5k
end n|&=6hiI
小记存储过程中经常用到的本周,本月,本年函数 qz]qG=wmL
Dateadd(wk,datediff(wk,0,getdate()),-1) `1(ED= |
Dateadd(wk,datediff(wk,0,getdate()),6) .=J- !{z
Dateadd(mm,datediff(mm,0,getdate()),0) ub-e! {
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $j\>T@
Dateadd(yy,datediff(yy,0,getdate()),0) {{Ox%Zm
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 3`%E;?2
上面的SQL代码只是一个时间段 RVttk )Ny
Dateadd(wk,datediff(wk,0,getdate()),-1) YZ+G7D>
Dateadd(wk,datediff(wk,0,getdate()),6) O[t?*m1/
就是表示本周时间段. )~=8Ssu
下面的SQL的条件部分,就是查询时间段在本周范围内的: uc@4fn
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .(q'7Q Z/
而在存储过程中 3pvqF,"~D
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) CYy=f-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Yft [)id