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。 G> >_G<x
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一、基础 Eq{TZV
1、说明:创建数据库 "-%H</
CREATE DATABASE database-name 9f`Pi:*+/
2、说明:删除数据库 ;wrgpP3
drop database dbname YvX I
3、说明:备份sql server =ndKG5
--- 创建 备份数据的 device 6Tnzg`0I
USE master 9_{!nQC.g
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' = ;d<Ikj
--- 开始 备份 (%}C
BACKUP DATABASE pubs TO testBack T:$_1I $
4、说明:创建新表 M='Kjc>e
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lfP|+=^B
根据已有的表创建新表: |#6Lcz7[
A:create table tab_new like tab_old (使用旧表创建新表) _(foJRr
B:create table tab_new as select col1,col2... from tab_old definition only ~JpUO~i/
5、说明:删除新表 ej+!|97M
drop table tabname mZyTo/\0
6、说明:增加一个列 `>Cx!sYhV
Alter table tabname add column col type .2xkf@OP
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。 nCU4a1rZ
7、说明:添加主键: Alter table tabname add primary key(col) >.|gmo>b
说明:删除主键: Alter table tabname drop primary key(col) at!?"u
8、说明:创建索引:create [unique] index idxname on tabname(col....) "RLb wm~
删除索引:drop index idxname AK
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注:索引是不可更改的,想更改必须删除重新建。 30@ GFaab
9、说明:创建视图:create view viewname as select statement ;H lv
删除视图:drop view viewname S J5kA`
10、说明:几个简单的基本的sql语句 j7&l&)5
选择:select * from table1 where 范围 /Ny&;Y
插入:insert into table1(field1,field2) values(value1,value2) HdM;c*K
删除:delete from table1 where 范围 zKNk(/y
更新:update table1 set field1=value1 where 范围 il~,y8WTU{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! JN_#
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排序:select * from table1 order by field1,field2 [desc] s><co]
总数:select count as totalcount from table1 uZ+<
求和:select sum(field1) as sumvalue from table1 )c/]
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平均:select avg(field1) as avgvalue from table1 mX89^
最大:select max(field1) as maxvalue from table1 q<VhP2R
最小:select min(field1) as minvalue from table1 !T*izMX}
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11、说明:几个高级查询运算词 E_K7.c4M
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A: UNION 运算符 >EY0-B
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。 |NI0zd
B: EXCEPT 运算符 k{~5pxd-t
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。 SpgVsz
C: INTERSECT 运算符 ' vwBG=9C
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。 utr_fFu
注:使用运算词的几个查询结果行必须是一致的。 DxlX-
12、说明:使用外连接 {#vo^& B
A、left outer join: `d8TA#|`
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。 am}zOr\
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 nMhc3t
B:right outer join: X\;y;pmRH
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。 <Wpz\U
C:full outer join: `JRdOe
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。 C.@TX
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二、提升 FB@G.f
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) &b_duWs
法一:select * into b from a where 1<>1 IY'S<)vOY
法二:select top 0 * into b from a +mJAIjH
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8L:0Wp
insert into b(a, b, c) select d,e,f from b; y3x_B@}BY
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) 4
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 344- ~i*
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. %vW@_A~
4、说明:子查询(表名1:a 表名2:b) [Y[|:_+5
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) N67m=wRx
5、说明:显示文章、提交人和最后回复时间 1peN@Yk2W
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b QZX+E
6、说明:外连接查询(表名1:a 表名2:b) y=t
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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"j7},P@
7、说明:在线视图查询(表名1:a ) NunT1ved
select * from (SELECT a,b,c FROM a) T where t.a > 1; n'SnqJ&}
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 j9%=^ZoQj
select * from table1 where time between time1 and time2 ;yr'K
select a,b,c, from table1 where a not between 数值1 and 数值2 qg_=5s
9、说明:in 的使用方法 m9r
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select * from table1 where a [not] in ('值1','值2','值4','值6') CGQ`i
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ='(:fHhhX
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Na4\)({
11、说明:四表联查问题: #(OL!B
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 ..... &W1cc#(
12、说明:日程安排提前五分钟提醒 !^y'G0
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 sPut@4[S
13、说明:一条sql 语句搞定数据库分页 DUaj]V{_^
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 "_lSw3
14、说明:前10条记录 O[!]/qP+.
select top 10 * form table1 where 范围 :p89J\
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.) KcHW>IBxdv
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Hd
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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 aPRF
(select a from tableA ) except (select a from tableB) except (select a from tableC) eKt~pzXwm
17、说明:随机取出10条数据 'Je;3"@
select top 10 * from tablename order by newid() _k&vW(O=:
18、说明:随机选择记录 {D$+~lO
select newid() Z<`QDBN"4
19、说明:删除重复记录 ^]K_k7`I
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) MFRM M%`
20、说明:列出数据库里所有的表名 +d<o2n4!
select name from sysobjects where type='U' [:Sl^ Z&6M
21、说明:列出表里的所有的 /@:I\&{f'9
select name from syscolumns where id=object_id('TableName') g/eE^o~;
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。 A\LMmg
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 >o.4sN@
显示结果: NSZ9M%7
type vender pcs #V@[<S2
电脑 A 1 W2'u]1bs
电脑 A 1 `Ps&N^[
光盘 B 2 13kl\<6
光盘 A 2 =XVw{\#9 b
手机 B 3 a0~LZQ?
手机 C 3 ]@0C1r
23、说明:初始化表table1 !Wgi[VB
TRUNCATE TABLE table1 |cs]98FEf
24、说明:选择从10到15的记录 @P@?KZ..v!
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc /V0[Urc@
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三、技巧 )\Am:?RH;
1、1=1,1=2的使用,在SQL语句组合时用的较多 7v't# =
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Xh+;$2l.B
如: uVN2}3!)Y
if @strWhere !='' l|v`B6(
begin 3N257]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere r'8qZJgm
end @q]4]U)
else c^3,e/H
begin iSbPOC7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ||D PIn]
end ,+~8R"
我们可以直接写成 q#=HBSyM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /*P) C'_M
2、收缩数据库 gWQ(B
--重建索引 ~[<C6{
DBCC REINDEX Wz%H?m:g#
DBCC INDEXDEFRAG KT[ZOtu
--收缩数据和日志 K
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DBCC SHRINKDB DQ<4`wE M
DBCC SHRINKFILE nr&bpA/
3、压缩数据库 ijP`fM8
dbcc shrinkdatabase(dbname) .exBU1Yk@
4、转移数据库给新用户以已存在用户权限 ?zex]!R
exec sp_change_users_login 'update_one','newname','oldname' >$,P )cB'
go .d I".L
5、检查备份集 \#4mPk_"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .do8\
6、修复数据库 |M`'
ALTER DATABASE [dvbbs] SET SINGLE_USER t W+"/<U
GO X$e*s\4
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK d~ +(g!
GO OClG dFJ|
ALTER DATABASE [dvbbs] SET MULTI_USER eAmI~oku
GO Z_[ P7P
7、日志清除 u@1 2:U$
SET NOCOUNT ON s_ t/
DECLARE @LogicalFileName sysname, HjIIhl?UY
@MaxMinutes INT, yDfH`]i)U
@NewSize INT l^Ob60)2
USE tablename -- 要操作的数据库名 elAWQE us
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 %N)B8A9kh
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ( <YBvpt4>
@NewSize = 1 -- 你想设定的日志文件的大小(M) {CV+1kz
-- Setup / initialize M!+J[q
DECLARE @OriginalSize int E*O($tS
SELECT @OriginalSize = size 3m= _a
FROM sysfiles b"WF]x|^
WHERE name = @LogicalFileName Q7rBc
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + +: x[cK
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + PChe w3
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [I=|"Ic~
FROM sysfiles 7mq&]4-G
WHERE name = @LogicalFileName -nXP<v=V
CREATE TABLE DummyTrans 4d\^
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, vof8bQ{&
@StartTime DATETIME, 2HtsSS#0Q
@TruncLog VARCHAR(255) ffG<hclk
SELECT @StartTime = GETDATE(), ~v%6*9
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q[_qZ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) KJRAW]?{
EXEC (@TruncLog) /i3JP}
-- Wrap the log if necessary. A+="0{P
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 0CX,"d_T,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ._^}M<o L
AND (@OriginalSize * 8 /1024) > @NewSize RI@\cJ\}
BEGIN -- Outer loop. 5afD;0D5TI
SELECT @Counter = 0 ])wdd>'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) RqgN<&g?
BEGIN -- update tGgxI D
INSERT DummyTrans VALUES ('Fill Log') LP6p
DELETE DummyTrans h{gFqkDoTI
SELECT @Counter = @Counter + 1 rz@qW2
END c`soVqT$?
EXEC (@TruncLog) j@>D]j
END !gve]>M
SELECT 'Final Size of ' + db_name() + ' LOG is ' + =..Bh8P71!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *Jgi=,!m
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' E
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FROM sysfiles j:h}ka/!p
WHERE name = @LogicalFileName 5E\.YqdV
DROP TABLE DummyTrans +P^
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SET NOCOUNT OFF Z1eT>6|]r
8、说明:更改某个表 P9/ (f$ =
exec sp_changeobjectowner 'tablename','dbo' xj3qOx$
9、存储更改全部表 !?nbB2,
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ZeP=}0TGjn
@OldOwner as NVARCHAR(128), 2)n`Bd
@NewOwner as NVARCHAR(128) .\ ;'>qy
AS rP:g`?*V
DECLARE @Name as NVARCHAR(128) 0G+Q^]0
DECLARE @Owner as NVARCHAR(128) wb0$FZzh
DECLARE @OwnerName as NVARCHAR(128) inWLIXC,
DECLARE curObject CURSOR FOR lS4r pbU_
select 'Name' = name, VHxBs
'Owner' = user_name(uid) t(u2%R4<d
from sysobjects e$J>z {
where user_name(uid)=@OldOwner oX|T&"&
order by name CRK%^3g
OPEN curObject i>YS%&O?
FETCH NEXT FROM curObject INTO @Name, @Owner aUaeK(x:H
WHILE(@@FETCH_STATUS=0) X`.##S KC
BEGIN n93q8U6m/U
if @Owner=@OldOwner J8qFdNK
begin =Kd'(ct
set @OwnerName = @OldOwner + '.' + rtrim(@Name) >v]^nJl
exec sp_changeobjectowner @OwnerName, @NewOwner h}
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end B*Tn@t W
-- select @name,@NewOwner,@OldOwner Fw 0m(7
FETCH NEXT FROM curObject INTO @Name, @Owner X'`n>1z
END 6KMO*v
close curObject |J-X3`^\H
deallocate curObject EhxpMTS
GO \ %Mcvb.?
10、SQL SERVER中直接循环写入数据 V$?6%\M^*
declare @i int @G4Z
set @i=1 YnEyL2SuU
while @i<30 j%6p:wDl
begin 2:38CdkYp
insert into test (userid) values(@i) 39v Bsc
set @i=@i+1 ~/L:$
end TxJk.c
小记存储过程中经常用到的本周,本月,本年函数 N3%#JdzZ$
Dateadd(wk,datediff(wk,0,getdate()),-1) P~j#8cH7
Dateadd(wk,datediff(wk,0,getdate()),6) )ros-dp`
Dateadd(mm,datediff(mm,0,getdate()),0) sY;h~a0n
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) (Ceru o S
Dateadd(yy,datediff(yy,0,getdate()),0) 9hzu!}~'I
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V'kBF2}
上面的SQL代码只是一个时间段 ]64Pk9z=
Dateadd(wk,datediff(wk,0,getdate()),-1) bBi>BP=
Dateadd(wk,datediff(wk,0,getdate()),6) 2j-l<!s
就是表示本周时间段. t/[2{'R4
下面的SQL的条件部分,就是查询时间段在本周范围内的: jj{:=lZB
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7nB4(A2[S4
而在存储过程中 MSCH6R"5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) QRju9x
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *$A`+D9