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。 BY*{j&^
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一、基础 &8=wkG%
1、说明:创建数据库 JSXJlau
CREATE DATABASE database-name %@C(H%obWd
2、说明:删除数据库 ~H<oqk:O-
drop database dbname
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3、说明:备份sql server >WYiOXYv
--- 创建 备份数据的 device 1P8XVI'
USE master ^a>3U l{
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' QuB`}rfLf
--- 开始 备份 ~rnbuIh
BACKUP DATABASE pubs TO testBack T"h@-UcTl
4、说明:创建新表 pr~%%fCh
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kHWW\?O
根据已有的表创建新表: 2EO WbN}M
A:create table tab_new like tab_old (使用旧表创建新表) O_v8R7 {
B:create table tab_new as select col1,col2... from tab_old definition only x}^:Bs+j
5、说明:删除新表
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drop table tabname pFB^l|\ ]
6、说明:增加一个列 cy_'QS$W
Alter table tabname add column col type j 3/ I=
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。 s&Bk@a8
7、说明:添加主键: Alter table tabname add primary key(col) ^nO0/nqz]
说明:删除主键: Alter table tabname drop primary key(col) xi+bBqg<.K
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;)nkY6-
删除索引:drop index idxname <@F.qMl
注:索引是不可更改的,想更改必须删除重新建。 ig-V^P
9、说明:创建视图:create view viewname as select statement T[?wbYfW
删除视图:drop view viewname Uz4!O
10、说明:几个简单的基本的sql语句 ~wejy3|@0
选择:select * from table1 where 范围 Gy;>.:n
插入:insert into table1(field1,field2) values(value1,value2) ?"hrCEHV{9
删除:delete from table1 where 范围 Z--A:D>
更新:update table1 set field1=value1 where 范围 d+caGpaR
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! kdgU1T@y.
排序:select * from table1 order by field1,field2 [desc] g4eEkG`XTS
总数:select count as totalcount from table1 5{z muv:
求和:select sum(field1) as sumvalue from table1 J\@ r~x5G
平均:select avg(field1) as avgvalue from table1 \*a7o GyH>
最大:select max(field1) as maxvalue from table1 E=*82Y=B
最小:select min(field1) as minvalue from table1 >Bw<THx
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11、说明:几个高级查询运算词 O c,E\~
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A: UNION 运算符 RJp Rsr
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。 k?bIu
B: EXCEPT 运算符 6%-RKQi
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。 L'Yg$9 Vz
C: INTERSECT 运算符 c*m7'\
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 mp'Z.4
注:使用运算词的几个查询结果行必须是一致的。 LL0Y$pHV
12、说明:使用外连接 (^{tu89ab
A、left outer join: thU9s%,
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。 =00c1v
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 Mzg zOM
B:right outer join: KD<smwXjG
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。 4 ZUTF3
C:full outer join: f]_{4Olk
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。 /VmtQ{KTt+
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二、提升 AT:L&~O.
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) i?3~Gog
法一:select * into b from a where 1<>1 ia9=&Hy])
法二:select top 0 * into b from a }O+a
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 2iWSk6%R
insert into b(a, b, c) select d,e,f from b; JI3x^[(Z
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) ro n-v"!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. i-jrF6&
4、说明:子查询(表名1:a 表名2:b) P
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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) Nc da~h
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5、说明:显示文章、提交人和最后回复时间 g7UZtpLTm
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Xf YbWR
6、说明:外连接查询(表名1:a 表名2:b) )K}-z+$)k
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mf W}^mu
7、说明:在线视图查询(表名1:a ) ufF>I
select * from (SELECT a,b,c FROM a) T where t.a > 1; i8h^~d2"
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 [yhK4A
select * from table1 where time between time1 and time2 1PN!1= F}
select a,b,c, from table1 where a not between 数值1 and 数值2 ke)}JU^"
9、说明:in 的使用方法 6(1S_b=a
select * from table1 where a [not] in ('值1','值2','值4','值6') ?Tlt(%f
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ymW? <\AD,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) mx!EuF$I
11、说明:四表联查问题: sU$<v( `"
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 ..... #iiXJnG
12、说明:日程安排提前五分钟提醒 L%`MoTpKq
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 }> ]`#s
13、说明:一条sql 语句搞定数据库分页 rj
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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 $~,J8?)(z
14、说明:前10条记录 2CF5qn}T
select top 10 * form table1 where 范围 FokSg[)5
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) (&KBYiwr
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) u9*7Buou^
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 dFl8 'D
(select a from tableA ) except (select a from tableB) except (select a from tableC) uqsVq0H
17、说明:随机取出10条数据 b[2 #t
select top 10 * from tablename order by newid() R*`=Bk0+
18、说明:随机选择记录 W9G1wU
select newid() E)iX`Xq|0{
19、说明:删除重复记录 4c]=kb GW
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (
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20、说明:列出数据库里所有的表名 3+/^
select name from sysobjects where type='U' u- }@^Y$M
21、说明:列出表里的所有的 Bfu/w
select name from syscolumns where id=object_id('TableName') VvUP;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。 eyzXHS*s;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 W,5_i7vr
显示结果: X@Bg_9\i
type vender pcs m7|S'{+!
电脑 A 1 +Ym#!"
电脑 A 1 [$D%]]/,
光盘 B 2 IcA]B?+
光盘 A 2 7NMy1'-q
手机 B 3 }3/|;0j$
手机 C 3 6n:oEXM>
23、说明:初始化表table1 %D49A-R
TRUNCATE TABLE table1 Y_FQB K U
24、说明:选择从10到15的记录 4g)$(5jI}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !DkIM}.
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三、技巧 ) E*-
1、1=1,1=2的使用,在SQL语句组合时用的较多 Kw =RqF
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 98Y1-Z^ .
如: RDOV+2K
if @strWhere !='' oi7Y?hTj
begin 8xt8kf*k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4jw q$G
end n+1`y8dy
else )tx2lyY:
begin @;X#/dZe
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' d-jZ 5nl(
end E^B3MyS^^
我们可以直接写成 )
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere RN2z/FUf
2、收缩数据库 Fu>;hx]s
--重建索引 T[- %b9h>
DBCC REINDEX nH}V:C
DBCC INDEXDEFRAG (7C$'T-ZK
--收缩数据和日志 i
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DBCC SHRINKDB p+;;01Z+_
DBCC SHRINKFILE 5Y>fVq{U?;
3、压缩数据库 f{-,"6Y1
dbcc shrinkdatabase(dbname) u/apnAW@M
4、转移数据库给新用户以已存在用户权限 #G\Ae:O
exec sp_change_users_login 'update_one','newname','oldname' a/n~#5-
go (\%J0kR3[
5、检查备份集 ~g}blv0q+B
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' lXRB"z
6、修复数据库 r-_-/O"l
ALTER DATABASE [dvbbs] SET SINGLE_USER eB9F35[
GO $+ORq3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK uMjL>YLq{?
GO g:YUuZ
ALTER DATABASE [dvbbs] SET MULTI_USER i(4.7{*
GO gNC'kCx0c
7、日志清除 BKK@_B"
SET NOCOUNT ON mGoNT
DECLARE @LogicalFileName sysname, 63'L58O
@MaxMinutes INT, 5R6QZVc
@NewSize INT NNBT.k3)
USE tablename -- 要操作的数据库名 nK`H;k
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 U45-R-
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 44pVZ5c
@NewSize = 1 -- 你想设定的日志文件的大小(M) `_x#`%!#2
-- Setup / initialize mr,GHx
DECLARE @OriginalSize int +hcJ!$J7
SELECT @OriginalSize = size +I@2,T(eG
FROM sysfiles E( *S]Z[
WHERE name = @LogicalFileName {<zE}7/2-
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wj8\eK)]L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + BkB9u&s^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' X=? \A{Y
FROM sysfiles P]7s1kgaS
WHERE name = @LogicalFileName w+{{4<+cd
CREATE TABLE DummyTrans 9hgIQl
(DummyColumn char (8000) not null) 1[-RIN;U8
DECLARE @Counter INT, f[q_eY
@StartTime DATETIME, y!x-R!3
@TruncLog VARCHAR(255) E O "
SELECT @StartTime = GETDATE(), GL^
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Uv(}x7e)
DBCC SHRINKFILE (@LogicalFileName, @NewSize) q)PSHr=Z
EXEC (@TruncLog) yMOYTN@]
-- Wrap the log if necessary. y2PxC. -
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m/WDJ$d
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) !lKDNQ8>["
AND (@OriginalSize * 8 /1024) > @NewSize \}Kad\)
BEGIN -- Outer loop. N@"e^i
SELECT @Counter = 0 r<;Y4<,BZ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `F~Fb S
BEGIN -- update <)+;Bg
INSERT DummyTrans VALUES ('Fill Log') +B7UGI
DELETE DummyTrans =H"%{VeC5
SELECT @Counter = @Counter + 1 _+gpdQq\p
END J?Rp
EXEC (@TruncLog) V/ZWyYxjLi
END #+^l3hMK
SELECT 'Final Size of ' + db_name() + ' LOG is ' + qz 29f
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + hDbZ62DDN
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1?r$Rx<R
FROM sysfiles BT(G9Pj;
WHERE name = @LogicalFileName hP/uS%X
DROP TABLE DummyTrans Y5TBWcGU%
SET NOCOUNT OFF ZRUA w,T *
8、说明:更改某个表 4VzSqb
exec sp_changeobjectowner 'tablename','dbo' ,88%eX|
9、存储更改全部表 8g/r8u~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch R!WeSgKCs
@OldOwner as NVARCHAR(128), K,*If Hi6[
@NewOwner as NVARCHAR(128) QzYaxNGv
AS eXdH)|l,\
DECLARE @Name as NVARCHAR(128) r<*Y1;7H'
DECLARE @Owner as NVARCHAR(128) HPK}Z|Vl
DECLARE @OwnerName as NVARCHAR(128) XlGB`P>?KD
DECLARE curObject CURSOR FOR /sl#M
select 'Name' = name, ik0w\*
'Owner' = user_name(uid) ^1ks`1
from sysobjects eoPoGC
where user_name(uid)=@OldOwner vf`]
order by name QEEX|WM
OPEN curObject =OR&,xt
FETCH NEXT FROM curObject INTO @Name, @Owner 7.C]ZcU
WHILE(@@FETCH_STATUS=0) ^Cg@'R9
BEGIN }80n5X<9
if @Owner=@OldOwner V{0 V/Nv
begin 7wqD_Xr
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ezd@>(hJ
exec sp_changeobjectowner @OwnerName, @NewOwner }Z`@Z'
end 4;w#mzd
-- select @name,@NewOwner,@OldOwner OmP(&t7
FETCH NEXT FROM curObject INTO @Name, @Owner s'@@q
END ]j(Ld\:L
close curObject :Czvwp{z
deallocate curObject !" : arK
GO 1xwq:vFC.
10、SQL SERVER中直接循环写入数据 &J=x[{R
declare @i int ^9kdd[
set @i=1 t*Wxvoxk
while @i<30 NO#^_N`#\
begin ,0$b8lb;x/
insert into test (userid) values(@i) ||?wRMV
set @i=@i+1 ,qlFk|A|
end tWdP5vfp
小记存储过程中经常用到的本周,本月,本年函数 EtB56FU\
Dateadd(wk,datediff(wk,0,getdate()),-1) zyI4E\
Dateadd(wk,datediff(wk,0,getdate()),6) x[%% )[d
Dateadd(mm,datediff(mm,0,getdate()),0) ;}k_2mr~
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) X .S8vlb4z
Dateadd(yy,datediff(yy,0,getdate()),0) Vs[!WJ
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) POQ1K
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上面的SQL代码只是一个时间段 LZu_-I
Dateadd(wk,datediff(wk,0,getdate()),-1) 5TdI
Dateadd(wk,datediff(wk,0,getdate()),6) W&^2Fb
就是表示本周时间段. F^');8~L
下面的SQL的条件部分,就是查询时间段在本周范围内的: @yjui
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ;Y16I#?;Kh
而在存储过程中 t,;b*ZR
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Ia)^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *$>$O%