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。 q165S
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一、基础 V.qH&FJ=l
1、说明:创建数据库 ~I;x_0iY4
CREATE DATABASE database-name -Q
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2、说明:删除数据库
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drop database dbname =H;'.!77Hx
3、说明:备份sql server *)
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--- 创建 备份数据的 device p'%S{v@5((
USE master -LUZ7,!/>o
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i '*!c
--- 开始 备份 n^hkH1vY
BACKUP DATABASE pubs TO testBack >1Hv c7DP
4、说明:创建新表 8zlvzp
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z}>F
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根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) Yk?q \1
B:create table tab_new as select col1,col2... from tab_old definition only B&B:P
5、说明:删除新表 .s,04xW\
drop table tabname gt(p%~
6、说明:增加一个列 %*npLDi
Alter table tabname add column col type p}pd&ut1
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。 :3D6OBkB
7、说明:添加主键: Alter table tabname add primary key(col) YG:^gi
说明:删除主键: Alter table tabname drop primary key(col) (Sgsy^|N
8、说明:创建索引:create [unique] index idxname on tabname(col....) tD}-&"REP
删除索引:drop index idxname 6B7*|R>
注:索引是不可更改的,想更改必须删除重新建。 I%Yq86
9、说明:创建视图:create view viewname as select statement u%yYLpaKf
删除视图:drop view viewname qGMU>J.;c
10、说明:几个简单的基本的sql语句 Xa#.GrH6
选择:select * from table1 where 范围 AH/o-$C&
插入:insert into table1(field1,field2) values(value1,value2) UQ;2g\([
删除:delete from table1 where 范围 ty"L&$bf
更新:update table1 set field1=value1 where 范围 !m9hL>5vR
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! rEC
排序:select * from table1 order by field1,field2 [desc] 00dY?d{[D
总数:select count as totalcount from table1 ]cS(2hP7
求和:select sum(field1) as sumvalue from table1 a)=|{QR>W
平均:select avg(field1) as avgvalue from table1 (?^ F }]
最大:select max(field1) as maxvalue from table1 ^p9V5o
最小:select min(field1) as minvalue from table1 F!u)8>s+z{
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11、说明:几个高级查询运算词 #\^=3A|b
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A: UNION 运算符 ZX`x9/0&
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。 `5wiXsNjLY
B: EXCEPT 运算符 w6X:39d
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。 4^:dmeMZ`
C: INTERSECT 运算符 -.MJ3
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。 oi,KA
注:使用运算词的几个查询结果行必须是一致的。 1hi,&h
12、说明:使用外连接 /}6y\3h
A、left outer join: wL3RcXW``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。 V?"U)Y@Y
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 f"*4R
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B:right outer join: =P9rOK=
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。 k\T]*A
C:full outer join: U>.5vK.+
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。 >]gB@tn[
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二、提升 LA59O@r
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) cl]W]^q-Cx
法一:select * into b from a where 1<>1 Te?PYV-
法二:select top 0 * into b from a p"~@q} 3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) v@yqTZ
insert into b(a, b, c) select d,e,f from b; c!wRq4
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) JBJ?|}5k4c
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 u?MhK#Mr
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Hf_
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4、说明:子查询(表名1:a 表名2:b) sn^ 3xAF
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) .|07IH/Di{
5、说明:显示文章、提交人和最后回复时间 VWK/(>TP
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CL7/J[TS
6、说明:外连接查询(表名1:a 表名2:b) ;y@zvec4
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c kJO Z;X=9/
7、说明:在线视图查询(表名1:a ) m,q)lbRl
select * from (SELECT a,b,c FROM a) T where t.a > 1; N5=}0s]e
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 ^mFsrw
select * from table1 where time between time1 and time2 w_@{v wM$A
select a,b,c, from table1 where a not between 数值1 and 数值2 qk3~]</
9、说明:in 的使用方法 .-&
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select * from table1 where a [not] in ('值1','值2','值4','值6') Et-|[ eL
10、说明:两张关联表,删除主表中已经在副表中没有的信息 jCNR63/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Nb_Glf
11、说明:四表联查问题: mrG?5.7W
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 ..... w ~crj$UM
12、说明:日程安排提前五分钟提醒 Ps\4k#aOv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 R_GA`U\ {
13、说明:一条sql 语句搞定数据库分页 -X%twy=
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 U"Bge\6x=
14、说明:前10条记录 y&8`NS#_p?
select top 10 * form table1 where 范围 -@#],s7
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) xy!E_CuC$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) t5K#nRd Z:
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 _:tS-Mx@5
(select a from tableA ) except (select a from tableB) except (select a from tableC) |4j6}g\
17、说明:随机取出10条数据 Z+);}>-5
select top 10 * from tablename order by newid() dQ-g\]d|
18、说明:随机选择记录 h@ ZC{B
select newid() O_th/hl
19、说明:删除重复记录 [qkW/qS
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5MCgmF*Y2
20、说明:列出数据库里所有的表名 <_eEpG}9
select name from sysobjects where type='U' LCA+y1LP-_
21、说明:列出表里的所有的 V3VTbgF
select name from syscolumns where id=object_id('TableName') |r;>2b/ x
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。 e<`?$tZ3
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >Jn` RsuV
显示结果: k$J!,!q
type vender pcs "10\y{`v^
电脑 A 1 V62lN<M
电脑 A 1 (]I=';\
光盘 B 2 Wrp+B[{r\
光盘 A 2 r]D>p&4
手机 B 3 }u0&> k|y
手机 C 3 G^SJhdO(Q
23、说明:初始化表table1 >rP[Xox'
TRUNCATE TABLE table1 iS.gN&\z^
24、说明:选择从10到15的记录 9yTkZ`M28
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc =1|p$@L`%
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三、技巧 ;ud"1wH
1、1=1,1=2的使用,在SQL语句组合时用的较多 b|kL*{;
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `uusUw-Gf
如: z+wegF
if @strWhere !='' c>/7E-T
begin '3Fb[md54
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere N:+EGmp
end ax;<idC}
else T5T[$%]6
begin \j wxW6>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' N z=P1&G'
end B]gyj
我们可以直接写成 W)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere #{?RE?nD
2、收缩数据库 FS @55mQ
--重建索引 @t$yg$Q?[
DBCC REINDEX gPd,
DBCC INDEXDEFRAG if\`M'3Xx
--收缩数据和日志 ){,Mv:#+T
DBCC SHRINKDB w}$;2g0=a<
DBCC SHRINKFILE FrLv%tK|
3、压缩数据库 jll|y0
dbcc shrinkdatabase(dbname) ;KmrBNF
4、转移数据库给新用户以已存在用户权限 (0_zp`)
exec sp_change_users_login 'update_one','newname','oldname' IIBS:&;+-
go bi@'m?XwJ
5、检查备份集 -T+'3</T
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' c`lL&*]
6、修复数据库 /FPO'} 6i
ALTER DATABASE [dvbbs] SET SINGLE_USER g@/}SJh/>
GO +s`cXTlFrk
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK PX/^*
GO JHZjf7g$k
ALTER DATABASE [dvbbs] SET MULTI_USER ^AOJ^@H^>
GO aAn p7\7
7、日志清除 QpoC-4F
SET NOCOUNT ON uXUuA/O5-
DECLARE @LogicalFileName sysname, THK^u+~LM
@MaxMinutes INT, N;>s|ET
@NewSize INT z?|bs?HKS
USE tablename -- 要操作的数据库名 KV6D0~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #RSUChe7w
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4N7|LxNNl_
@NewSize = 1 -- 你想设定的日志文件的大小(M) Q:y'G9b
-- Setup / initialize .VUnOdI
DECLARE @OriginalSize int wHx_lsY;
SELECT @OriginalSize = size c_.Fe'E
FROM sysfiles 10m|?
WHERE name = @LogicalFileName Up_"qD6
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2!b##`UjA7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }:J-o
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' cb{"1z
FROM sysfiles *1_Ef).
WHERE name = @LogicalFileName ,\RR@~u'
CREATE TABLE DummyTrans rp[3?-fk
(DummyColumn char (8000) not null) n3-VqYUP
DECLARE @Counter INT, c"1Z,M;G
@StartTime DATETIME, "*MF=VB1
@TruncLog VARCHAR(255) 44YKS>Cq
SELECT @StartTime = GETDATE(), A
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <viC~=k;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) D$NpyF.87
EXEC (@TruncLog) +~y>22Zfg
-- Wrap the log if necessary. I6@"y0I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 88?O4)c
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 0plX"NU
AND (@OriginalSize * 8 /1024) > @NewSize aS\$@41"
BEGIN -- Outer loop. F=#V/ #ia
SELECT @Counter = 0 Nqz6_!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "{t]~urLd
BEGIN -- update Unb3
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INSERT DummyTrans VALUES ('Fill Log') n;>=QG
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DELETE DummyTrans vEGI
SELECT @Counter = @Counter + 1 )%n$_N n
END WNQ<XBqAw
EXEC (@TruncLog) Qj(ppep\U"
END E7aG&K
SELECT 'Final Size of ' + db_name() + ' LOG is ' + P$*Ngt
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I:UDEoQo
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' H3ovF
FROM sysfiles +PKsiUJ|
WHERE name = @LogicalFileName fz2}M:u
DROP TABLE DummyTrans B##X94aTT
SET NOCOUNT OFF o[+t}hC[
8、说明:更改某个表 MHye!T6fO\
exec sp_changeobjectowner 'tablename','dbo' .sFN[>)
9、存储更改全部表 M:iH7K
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ,_,*I/o>B
@OldOwner as NVARCHAR(128), YgS,5::SU
@NewOwner as NVARCHAR(128) 1)zXv
AS 4i+%~X@p
DECLARE @Name as NVARCHAR(128) 0'YP9-C3
DECLARE @Owner as NVARCHAR(128) 8?YeaMIBB
DECLARE @OwnerName as NVARCHAR(128) v=cQ`nou
DECLARE curObject CURSOR FOR uI%7jA~@
select 'Name' = name, f#w
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'Owner' = user_name(uid) &oy')\H
from sysobjects PB8g4-?p6
where user_name(uid)=@OldOwner ylQj2B,CB
order by name $&KkZ
OPEN curObject k6RVP:V
FETCH NEXT FROM curObject INTO @Name, @Owner n9`]}bnX
WHILE(@@FETCH_STATUS=0) $60`Hh 4/
BEGIN af9KtX+
if @Owner=@OldOwner n^O!93a
begin FoH1O+e
set @OwnerName = @OldOwner + '.' + rtrim(@Name) BOq9\g`5s
exec sp_changeobjectowner @OwnerName, @NewOwner cGdYfi
end 5$cjCjY
-- select @name,@NewOwner,@OldOwner DZ\K7-
FETCH NEXT FROM curObject INTO @Name, @Owner : T7(sf*!*
END rKyulgP
close curObject Z*UVbyC
deallocate curObject 32%Fdz1S
GO ;+6><O!G
10、SQL SERVER中直接循环写入数据 #d-zH:uq
declare @i int 3JBXGT0gJ
set @i=1 A>2 _I)
while @i<30 C])s'XTs
begin 1# z@D(
insert into test (userid) values(@i) ugE!EEy[^
set @i=@i+1 b.@4yW
end [Z#Sj=z
小记存储过程中经常用到的本周,本月,本年函数 >$E;."a
Dateadd(wk,datediff(wk,0,getdate()),-1) DZnqCu"J
Dateadd(wk,datediff(wk,0,getdate()),6) Ef28
Dateadd(mm,datediff(mm,0,getdate()),0) Vdd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }zQgS8PQH
Dateadd(yy,datediff(yy,0,getdate()),0) U&Vu%+B
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) "`4ky]
上面的SQL代码只是一个时间段 18QqZ,t
Dateadd(wk,datediff(wk,0,getdate()),-1) z8JW iRn
Dateadd(wk,datediff(wk,0,getdate()),6) -eyF9++`
就是表示本周时间段. Bdb}4X rL
下面的SQL的条件部分,就是查询时间段在本周范围内的: W0~G`A(:;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 09jE7g @X}
而在存储过程中 8B?U\cfa^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) s hH2/.>
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 83t/\x,Q