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。 7! A%6
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一、基础 DJ2]NA$Q*
1、说明:创建数据库 K
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CREATE DATABASE database-name N@du.d:
2、说明:删除数据库 ~m;MM)_V
drop database dbname ,B/p1^;.
3、说明:备份sql server {J6sM$aj
--- 创建 备份数据的 device d ;7pri)B
USE master y:6'&`L
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1j)!d$8
--- 开始 备份 qer'V
BACKUP DATABASE pubs TO testBack QmkC~kK1.
4、说明:创建新表 +` Y ?-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) LK-6z w5=(
根据已有的表创建新表: tP^mq>
A:create table tab_new like tab_old (使用旧表创建新表) "6o}qeB l
B:create table tab_new as select col1,col2... from tab_old definition only >^\>-U|
5、说明:删除新表 7[.Q.3FL
drop table tabname uW--
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6、说明:增加一个列 _>)"+z^r
Alter table tabname add column col type JLV}Fw
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 1S.e5{
7、说明:添加主键: Alter table tabname add primary key(col) qLi1yH
说明:删除主键: Alter table tabname drop primary key(col)
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8、说明:创建索引:create [unique] index idxname on tabname(col....) S%gO6&^
删除索引:drop index idxname R{Kd%Y:2Y
注:索引是不可更改的,想更改必须删除重新建。 byj mH
9、说明:创建视图:create view viewname as select statement po$ynp756
删除视图:drop view viewname ;gu>;_
10、说明:几个简单的基本的sql语句 0}7Rm>
选择:select * from table1 where 范围 ci NTYow
插入:insert into table1(field1,field2) values(value1,value2) ~JRuMP
删除:delete from table1 where 范围 G~hILW^
更新:update table1 set field1=value1 where 范围 88=FPEU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! cyP*QW[
排序:select * from table1 order by field1,field2 [desc] $cpQ7
总数:select count as totalcount from table1 3!w>"h0(
求和:select sum(field1) as sumvalue from table1 1eyyu!
平均:select avg(field1) as avgvalue from table1 f(MHU
最大:select max(field1) as maxvalue from table1 w7?9e#>Z
最小:select min(field1) as minvalue from table1 714nUA872
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11、说明:几个高级查询运算词 `xAJy5
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A: UNION 运算符 )n[Mh!mn
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。 b0=AQ/:
B: EXCEPT 运算符 iZUz6
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。 i-vJ&}}
C: INTERSECT 运算符 ^^Q32XC,
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。 VP[!ji9P
注:使用运算词的几个查询结果行必须是一致的。 Gz5@1CF
12、说明:使用外连接 "/-v 9
A、left outer join: 9@*>$6
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 }`FC__
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k*6eZ 7
B:right outer join: N6
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 >@e%,z
C:full outer join: /,%o<Ql9
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 HZ4
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二、提升 I2!HXMrp
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) q8v!{Os+#
法一:select * into b from a where 1<>1 wTbIS~!gF
法二:select top 0 * into b from a {#Cm> @')
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "A`'~]/hE
insert into b(a, b, c) select d,e,f from b; M
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) <rmV$_
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 U.h PC3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. D5vtZu!"
4、说明:子查询(表名1:a 表名2:b) 1vudT&
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) iL'
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5、说明:显示文章、提交人和最后回复时间 kakWXGeR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b j=QjvWD
6、说明:外连接查询(表名1:a 表名2:b) w~?eX/;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c TL:RB)- <
7、说明:在线视图查询(表名1:a ) #T`+~tW'|
select * from (SELECT a,b,c FROM a) T where t.a > 1; *heQ@ww
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 L<]PK4
select * from table1 where time between time1 and time2 ^P`'qfZ
select a,b,c, from table1 where a not between 数值1 and 数值2 ,R6$SrNcd
9、说明:in 的使用方法 y^BM*C I
select * from table1 where a [not] in ('值1','值2','值4','值6') <L#r6y~H
10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) v]S8!wU
11、说明:四表联查问题: .1lc'gu5y
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 ..... 3_/d=ZI\
12、说明:日程安排提前五分钟提醒 <2A'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 a8c]B/
13、说明:一条sql 语句搞定数据库分页 9oz)E>K4f
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 vLS6Gb't
14、说明:前10条记录 SJ@_eir\o
select top 10 * form table1 where 范围 F\<i>LWT'
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.) AOUO',v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }1 ^.A84a
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 .JjuY'-Q
(select a from tableA ) except (select a from tableB) except (select a from tableC) j
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17、说明:随机取出10条数据 (Cd`~*5
select top 10 * from tablename order by newid() \zyGJyy.
18、说明:随机选择记录 `rQl{$9IC
select newid() }"tYb6*
19、说明:删除重复记录 F4Z0g*^x
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Zv7)+Q
20、说明:列出数据库里所有的表名 x|5/#H
select name from sysobjects where type='U' &ayoTE^0,
21、说明:列出表里的所有的 ]uf_"D
select name from syscolumns where id=object_id('TableName') j]^]p;An
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。 [%:NR
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 Ccmbdw,Z5
显示结果:
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type vender pcs Q5JeL6t
电脑 A 1 krU2S-
电脑 A 1 ^;bkU|(`6
光盘 B 2 R)z|("%ec
光盘 A 2 ln7.>.F
手机 B 3 &5<lQ1
手机 C 3 $4pW#4/4
23、说明:初始化表table1 +0DIN4Y(4
TRUNCATE TABLE table1 GS%Dn^l
24、说明:选择从10到15的记录 uv!/DX#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc fCR;Fk2B
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三、技巧 3-D!Z S&
1、1=1,1=2的使用,在SQL语句组合时用的较多 N8TO"`wdbs
"where 1=1" 是表示选择全部 "where 1=2"全部不选, o hCPNm
如: XijQ)}'C3
if @strWhere !='' hAdEq$
begin WjB[e>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CgWj9 [
end FKP^f\!M
else qsp,Usu/
begin F)G#\r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "7DPsPs
end >J1o@0tk
我们可以直接写成 c=gUY~Rl
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Zl)|x%z
2、收缩数据库 s0u$DM2
--重建索引 =|V3cM4'
DBCC REINDEX 1 /`>Eh
DBCC INDEXDEFRAG t9}XO M*
--收缩数据和日志 Jc+U$h4
DBCC SHRINKDB <|4j<U
DBCC SHRINKFILE ?g&]*zc^\
3、压缩数据库 7)T+!>
dbcc shrinkdatabase(dbname) TJ<PT
4、转移数据库给新用户以已存在用户权限 \r2w@F{C
exec sp_change_users_login 'update_one','newname','oldname' fITml6mbE
go ~gf$ L9
5、检查备份集 7]Egu D4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' |Yx8Ez
6、修复数据库 v7-'H/d.
ALTER DATABASE [dvbbs] SET SINGLE_USER A28w/=e7
GO wcOAyo5(n
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK I'gnw~
GO 8P 8"dN[
ALTER DATABASE [dvbbs] SET MULTI_USER |lv4X}H
GO 86Rit!ih
7、日志清除 {MS&t09Wh
SET NOCOUNT ON R8KL4g-d
DECLARE @LogicalFileName sysname, Pzqgg43Xf
@MaxMinutes INT, cE3co(j
@NewSize INT UaBR;v-.B3
USE tablename -- 要操作的数据库名 ;9~z_orNQZ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #O~Y[''C5X
@MaxMinutes = 10, -- Limit on time allowed to wrap log. p#&6Ed*V
@NewSize = 1 -- 你想设定的日志文件的大小(M) oTL "]3`'
-- Setup / initialize IkvH8E
DECLARE @OriginalSize int ,iyIF~1~#>
SELECT @OriginalSize = size kxP6#8*:
FROM sysfiles %guot~S|
WHERE name = @LogicalFileName \8pbPo=x
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %nIjRmqM~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |LQmdgVr$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' YcI]_[
FROM sysfiles ldxUq,p
WHERE name = @LogicalFileName L/ZZe5I
CREATE TABLE DummyTrans ]u:NE'0Xy
(DummyColumn char (8000) not null) WRgz]=W3w
DECLARE @Counter INT, _+{s^n=
@StartTime DATETIME, ("aYjKk
@TruncLog VARCHAR(255) G$Dg*<
SELECT @StartTime = GETDATE(), e' Zg F~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5mV'k"Om#"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) czp5MU_^
EXEC (@TruncLog) /oI''O%M
-- Wrap the log if necessary. acH.L_B:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired TQ BL!w
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) E )PEKWK\
AND (@OriginalSize * 8 /1024) > @NewSize ugCc&~`
BEGIN -- Outer loop. [:o#d`^
SELECT @Counter = 0 bUBuJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _V;J7Vz
BEGIN -- update /i]Gg
\)
INSERT DummyTrans VALUES ('Fill Log') QW!'A`*x
DELETE DummyTrans 4M:oa#gh@
SELECT @Counter = @Counter + 1 qjWgyhL
END T4UY%E!0
EXEC (@TruncLog) koUH>J:
END ^a(q7ZfY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Vf:t!'WD?2
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + MDlCU
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' iZ58;`
FROM sysfiles l})uYae/
WHERE name = @LogicalFileName K)k!`du!6
DROP TABLE DummyTrans QCjmg5bf'7
SET NOCOUNT OFF vb%\q sf
8、说明:更改某个表 | zA ey\
exec sp_changeobjectowner 'tablename','dbo' VTF),e!
9、存储更改全部表 T.xW|Iwx
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $Fn# b|e
@OldOwner as NVARCHAR(128), :9)>!+|'
@NewOwner as NVARCHAR(128) A[b'MNsv
AS iX,Qh2(ig
DECLARE @Name as NVARCHAR(128) 7#RW4ZM
DECLARE @Owner as NVARCHAR(128) j/W#=\xz
DECLARE @OwnerName as NVARCHAR(128) KL xg
DECLARE curObject CURSOR FOR lmod8B
select 'Name' = name, A*$vk2VWw
'Owner' = user_name(uid) 9|go`^*.
from sysobjects `0so)2ty+
where user_name(uid)=@OldOwner 'Hq}h)`
order by name u%T.XgY=j
OPEN curObject H<qR^a
FETCH NEXT FROM curObject INTO @Name, @Owner j\ )Qn2r
WHILE(@@FETCH_STATUS=0) ]s u\[?l
BEGIN Xc@4(Nyp
if @Owner=@OldOwner 0!^{V:DtQ
begin R; IB o
set @OwnerName = @OldOwner + '.' + rtrim(@Name) -j(/5.a
exec sp_changeobjectowner @OwnerName, @NewOwner k<St:X%.O
end s*VZLKO
-- select @name,@NewOwner,@OldOwner HezCRtxRcc
FETCH NEXT FROM curObject INTO @Name, @Owner tvg7mU]l
END %Jw;c`JM
close curObject EswM#D9(4
deallocate curObject ?1[go+56X
GO 2Aff3]-:Gd
10、SQL SERVER中直接循环写入数据 |S.-5CAh4
declare @i int H6~QSe0l
set @i=1 8*|@A6ig
while @i<30 Kr9 @
begin 7%0PsF _
insert into test (userid) values(@i) l
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set @i=@i+1 ,,i;6q_f
end 04,]upC${W
小记存储过程中经常用到的本周,本月,本年函数 (5atU |8r
Dateadd(wk,datediff(wk,0,getdate()),-1) )2R:P`U
Dateadd(wk,datediff(wk,0,getdate()),6) h'N,oDB)
Dateadd(mm,datediff(mm,0,getdate()),0) HC$_p,9OV
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) D L$P
Dateadd(yy,datediff(yy,0,getdate()),0) ;KnnAZJ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) wD*_S}]
上面的SQL代码只是一个时间段 c|I{U[(U
Dateadd(wk,datediff(wk,0,getdate()),-1) Ble <n6
Dateadd(wk,datediff(wk,0,getdate()),6) ^*Ca+22xO
就是表示本周时间段. ptUnV3h
下面的SQL的条件部分,就是查询时间段在本周范围内的: H1q>UU:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d,$[633It}
而在存储过程中 0C0iAp
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cnI!}Bu
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) G66vzwO