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。 ypG*41
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一、基础 c?EvrtND
1、说明:创建数据库 8
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CREATE DATABASE database-name Y I;iG[T,&
2、说明:删除数据库 G" E_4YkJ
drop database dbname >;hAw!|#
3、说明:备份sql server !&hqj$>-}
--- 创建 备份数据的 device
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USE master ~Ck OiWC0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :>;F4gGVG
--- 开始 备份 jLt3jN
BACKUP DATABASE pubs TO testBack LtX53c
4、说明:创建新表 e2NK7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) v\4<6Z:4
根据已有的表创建新表: *9$SFe|&n:
A:create table tab_new like tab_old (使用旧表创建新表) .,p=e$x]
B:create table tab_new as select col1,col2... from tab_old definition only j}",+Hv
5、说明:删除新表 `R:W5_n
drop table tabname zD<W`_z
6、说明:增加一个列 Y
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Alter table tabname add column col type @`C'tfG/4
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 D?"P\b[/
7、说明:添加主键: Alter table tabname add primary key(col) =t)qy5
说明:删除主键: Alter table tabname drop primary key(col) eh<mJL%T
8、说明:创建索引:create [unique] index idxname on tabname(col....) :&TM0O
删除索引:drop index idxname <\ <o#Vq
注:索引是不可更改的,想更改必须删除重新建。 C$PS@4'U
9、说明:创建视图:create view viewname as select statement 'UWkJ2:!
删除视图:drop view viewname tkcs6uy
10、说明:几个简单的基本的sql语句 oC49c~`8
选择:select * from table1 where 范围 znTi_S
插入:insert into table1(field1,field2) values(value1,value2) 1<73uR&b%
删除:delete from table1 where 范围 >8kXa.)84
更新:update table1 set field1=value1 where 范围 8$A0q%n
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ls:oC},p*
排序:select * from table1 order by field1,field2 [desc] ^M6lF5
总数:select count as totalcount from table1 e9RYk:O
求和:select sum(field1) as sumvalue from table1 1J/'R37lP
平均:select avg(field1) as avgvalue from table1 $8UW^#Bpq
最大:select max(field1) as maxvalue from table1 =hFY-~U
最小:select min(field1) as minvalue from table1 $7DW-TA
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11、说明:几个高级查询运算词 bV&9>fC
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A: UNION 运算符 f%@~|:G:
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 yT_W\"=8
B: EXCEPT 运算符 `}#rcDK
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =FhP$r*
C: INTERSECT 运算符 \8QOZjy
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?l<`sTO
注:使用运算词的几个查询结果行必须是一致的。 _8u TK%|
12、说明:使用外连接 5kTs7zJ^
A、left outer join: *YeQCt-l
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。 jBYvOy*$Q
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 ^g vTc+|
B:right outer join: zU~ Ff"<
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。 2vjkThh`I
C:full outer join: ?#=xx.cF
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。 6d6cZGS[:
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二、提升 b-VygLN
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +|obU9M
法一:select * into b from a where 1<>1 e!jy6t
法二:select top 0 * into b from a =b:XL#VA
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d2#NRqgQ
insert into b(a, b, c) select d,e,f from b; <z,)4z++
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) 8A3/@Z;0S
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #\lvzMjCC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. F5
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4、说明:子查询(表名1:a 表名2:b) j9[I6ko5'
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) $YEm(:v$
5、说明:显示文章、提交人和最后回复时间 -9t"$)&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b F&czD;F
6、说明:外连接查询(表名1:a 表名2:b) :IS?si5|
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1$vG Q
7、说明:在线视图查询(表名1:a ) OA3J(4!"W
select * from (SELECT a,b,c FROM a) T where t.a > 1; MZ,1 mR
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 b`#YJpA
select * from table1 where time between time1 and time2 ,7&\jET5^0
select a,b,c, from table1 where a not between 数值1 and 数值2 Qs,\P^n
9、说明:in 的使用方法 BjvQ6M{Y"+
select * from table1 where a [not] in ('值1','值2','值4','值6') 3?*dv14
10、说明:两张关联表,删除主表中已经在副表中没有的信息 2 3PRb<q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -| m3=#
11、说明:四表联查问题: JK =A=
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 ..... IHO*%3mA/
12、说明:日程安排提前五分钟提醒 }b(hD|e
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Th9V8Rg+E
13、说明:一条sql 语句搞定数据库分页 W`Gbo
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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 ?^%[*OCCC!
14、说明:前10条记录 ,]2?S5R
select top 10 * form table1 where 范围 x'`{#bKD
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.) gE2(E0H
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) cWkg.ri-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 1WMZ$vsQUb
(select a from tableA ) except (select a from tableB) except (select a from tableC) jDY
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17、说明:随机取出10条数据 fAULuF
select top 10 * from tablename order by newid() -`k>(\Q<d
18、说明:随机选择记录 9BtGzI\
select newid() b}R_@_<u
19、说明:删除重复记录 8{G!OBxc\.
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) X#&5?oq`
20、说明:列出数据库里所有的表名 5eori8gr7
select name from sysobjects where type='U' rV%68x9
21、说明:列出表里的所有的 Vpnk>GWD
select name from syscolumns where id=object_id('TableName') ,_kw}_n=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 jy!]MAP#Gk
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type
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显示结果: Df4O~j$U"s
type vender pcs .A< HM}
电脑 A 1 Og7yT{h_
电脑 A 1 AhF@
光盘 B 2 YP02/*'
光盘 A 2 gt}Atr6>_
手机 B 3 DA
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手机 C 3 `}),wBq
23、说明:初始化表table1 zVS{X=u
TRUNCATE TABLE table1 1YV1Xnn,
24、说明:选择从10到15的记录 6m;>R%S_
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *m"9F'(Sd
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三、技巧 ~JL
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1、1=1,1=2的使用,在SQL语句组合时用的较多 k={D!4kKz
"where 1=1" 是表示选择全部 "where 1=2"全部不选, b\}a
如: caQ1SV^{9
if @strWhere !='' V|'@D#\
begin "mJo<i}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere l ubsL I
end 7#E/Q~]'6
else Z{^!z
begin B46:LQ9[
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' n>v1<^
end *LB-V%{|'
我们可以直接写成 bPOPoq1#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere e#;43=/Ia
2、收缩数据库 "rn
--重建索引 G!I++M"
DBCC REINDEX {A0F/#M]
DBCC INDEXDEFRAG %Y ZCdS
--收缩数据和日志 fxcE1=a
DBCC SHRINKDB FvT4?7-
DBCC SHRINKFILE *1dZs~_
3、压缩数据库 W8 g13oAu"
dbcc shrinkdatabase(dbname) 1-p#}VX
4、转移数据库给新用户以已存在用户权限 SSF:PTeG>
exec sp_change_users_login 'update_one','newname','oldname' i`sZP#h
go MM32\}Y6
5、检查备份集 QfEJU8/5d
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ,9ueHE
6、修复数据库 mx}5":}
ALTER DATABASE [dvbbs] SET SINGLE_USER h~#F2#.
GO \ZcI{t'a
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >k"O3Pc@
GO SdlO]y9E
ALTER DATABASE [dvbbs] SET MULTI_USER O<s7VHj
GO AJ/Hw>>$?m
7、日志清除 4xW~@meNB
SET NOCOUNT ON 2`]c&k;]
DECLARE @LogicalFileName sysname, %.$!VTO"
@MaxMinutes INT,
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@NewSize INT n8EKTuy
USE tablename -- 要操作的数据库名 Zl3l=x h
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 la{?&75]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. = cxO@Fu
@NewSize = 1 -- 你想设定的日志文件的大小(M) U[pHT _U
-- Setup / initialize J0IKI,X.
DECLARE @OriginalSize int _W(xO
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SELECT @OriginalSize = size Nt8"6k_
FROM sysfiles \*CXXp`
WHERE name = @LogicalFileName c_qox
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wBpt
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ia\Gmh
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' %t&Lq }e
FROM sysfiles h:pgN,W}
WHERE name = @LogicalFileName PNAvT$0LaZ
CREATE TABLE DummyTrans rmw}Ui"
(DummyColumn char (8000) not null) qOG@MR(5
DECLARE @Counter INT, ByjfPb#
@StartTime DATETIME, 15 {^waR6
@TruncLog VARCHAR(255) 3|$?T|#B
SELECT @StartTime = GETDATE(), RgoF4g+@
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *m"@*O'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) L?u{v X
EXEC (@TruncLog) \)28,`
-- Wrap the log if necessary. +iN!$zF5]
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired x}a?B
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) GThGV"
AND (@OriginalSize * 8 /1024) > @NewSize qsp3G7\'=
BEGIN -- Outer loop. vhOh3
SELECT @Counter = 0 E~q3o*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ds]
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BEGIN -- update 0i[t[_sce
INSERT DummyTrans VALUES ('Fill Log') bP$e1I3`
DELETE DummyTrans 7x`$ A
SELECT @Counter = @Counter + 1 MMa`}wSs
END E*)A!2rlK
EXEC (@TruncLog) _\4r~=`HQ
END *}:P
SELECT 'Final Size of ' + db_name() + ' LOG is ' + PYQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + \KJTR0EB:>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 4Ty?>'*|
FROM sysfiles xy>$^/[$
WHERE name = @LogicalFileName ,eebO~7vB
DROP TABLE DummyTrans lg-`zV3
SET NOCOUNT OFF (1S9+H>g
8、说明:更改某个表 =4q 5KI
exec sp_changeobjectowner 'tablename','dbo' L`M{bRl+1
9、存储更改全部表 !(bYh`Uy
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ui8$ F
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@OldOwner as NVARCHAR(128), ;Uch
@NewOwner as NVARCHAR(128) C,;<SV2#
AS >7a
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DECLARE @Name as NVARCHAR(128) fPN/Mxu
DECLARE @Owner as NVARCHAR(128) r|Uz?
DECLARE @OwnerName as NVARCHAR(128) G{.=27
DECLARE curObject CURSOR FOR 7oLl RU
select 'Name' = name, 2 br>{^T
'Owner' = user_name(uid) KX x+J}n
from sysobjects 8u[.s`^
where user_name(uid)=@OldOwner 71Q`B#t0'Z
order by name mn1!A`$
OPEN curObject :F5(]g 7
FETCH NEXT FROM curObject INTO @Name, @Owner 6R m d t
WHILE(@@FETCH_STATUS=0) fC^d@4ha
BEGIN >.39OQ#
if @Owner=@OldOwner \zcSfNE
begin 0F!Uai1
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fc:87ZR{K
exec sp_changeobjectowner @OwnerName, @NewOwner 7g8\q@',
end im>/$!&OyI
-- select @name,@NewOwner,@OldOwner $hJ 4=F
FETCH NEXT FROM curObject INTO @Name, @Owner jMWTNZ
END OvdBUcp[
close curObject +:#g6(P]
deallocate curObject 5Q}HLjG8Z
GO F9w2+z.
10、SQL SERVER中直接循环写入数据 .h
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declare @i int tm34Z''.>
set @i=1 E]{0lG`l
while @i<30 ViOXmK"
begin oMn'{+(w
insert into test (userid) values(@i) 8f?o?c|
set @i=@i+1 ~Gg19x.#uW
end `h'Ab63
小记存储过程中经常用到的本周,本月,本年函数 %,N-M]Jf
Dateadd(wk,datediff(wk,0,getdate()),-1) "}uu-5]3
Dateadd(wk,datediff(wk,0,getdate()),6) T?n [1%K
Dateadd(mm,datediff(mm,0,getdate()),0) P'5Lu
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) C>l (4*S
Dateadd(yy,datediff(yy,0,getdate()),0) UHl1>(U
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >SZuN"r8`
上面的SQL代码只是一个时间段 AnsJ3C
Dateadd(wk,datediff(wk,0,getdate()),-1) 6(Cjak+~!
Dateadd(wk,datediff(wk,0,getdate()),6) fb8xs<
就是表示本周时间段. K/(Z\lL
下面的SQL的条件部分,就是查询时间段在本周范围内的: kad$Fp39
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) "H=fWz5z
而在存储过程中 VF-[O
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ojWf]$^y}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^*NOG\BK@