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。 $,,>R[; w
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一、基础 <bZm
1、说明:创建数据库 #]DZrD&q
CREATE DATABASE database-name xqC<p`?4
2、说明:删除数据库 ?b7g9 G4
drop database dbname Q_0x6]/!
3、说明:备份sql server h4\ 6h
--- 创建 备份数据的 device LsQ8sFP_"
USE master *m&:
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `-EH0'w~"
--- 开始 备份 |ch^eb^7"
BACKUP DATABASE pubs TO testBack G+X[R^RD
4、说明:创建新表 d74g|`/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) i;hc]fYb=K
根据已有的表创建新表: niHL/\7u
A:create table tab_new like tab_old (使用旧表创建新表) jJ"EGFa8
B:create table tab_new as select col1,col2... from tab_old definition only s
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5、说明:删除新表 jc.JX_/
drop table tabname B%J%TR_
6、说明:增加一个列 5J+V:Xu{
Alter table tabname add column col type }j(2Dl
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 .`&/QiD
7、说明:添加主键: Alter table tabname add primary key(col) 1uS-Tx
说明:删除主键: Alter table tabname drop primary key(col) :-\ yy
8、说明:创建索引:create [unique] index idxname on tabname(col....) %^5 @z1d,
删除索引:drop index idxname >`<2}Me6
注:索引是不可更改的,想更改必须删除重新建。 Fv);5LD
9、说明:创建视图:create view viewname as select statement ^_KD&%M6
删除视图:drop view viewname bxdXZBn
10、说明:几个简单的基本的sql语句 iE^a%|?}
选择:select * from table1 where 范围 V}|v!h[O8
插入:insert into table1(field1,field2) values(value1,value2) ?
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删除:delete from table1 where 范围 yb4tJu$
更新:update table1 set field1=value1 where 范围 ZutB_uW
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! loUl$X.u
排序:select * from table1 order by field1,field2 [desc] fEw=I7{Y
总数:select count as totalcount from table1 ^'[@M'`~L
求和:select sum(field1) as sumvalue from table1 $C05iD
平均:select avg(field1) as avgvalue from table1 O GFE*
最大:select max(field1) as maxvalue from table1 +:,`sdv6o
最小:select min(field1) as minvalue from table1 rFq@]t3q
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11、说明:几个高级查询运算词 R@<_Hb;Aeb
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A: UNION 运算符 j|&DP-@g/
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 |#&V:GZp
B: EXCEPT 运算符 7/|F9fF@M
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 i2:+h}o$e
C: INTERSECT 运算符 7SK3
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。 %[nR|a<
注:使用运算词的几个查询结果行必须是一致的。 zvGK6qCk
12、说明:使用外连接 TsX+. i'
A、left outer join: 9PKoNd^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。 H9~%#&fF
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 m(Y.X=EZr
B:right outer join: -jVaS wt
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。 Be{/2jU%
C:full outer join: 98A(jsj
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。 Dr6s^}}~n
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二、提升 ("?&p3];b
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) NuD[-;N]
法一:select * into b from a where 1<>1 |)-|2cPRur
法二:select top 0 * into b from a b4v(k(<
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jJUGZVM6)
insert into b(a, b, c) select d,e,f from b; &]VQR2J}:
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) !{Q:(B#ec
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {xv?wenE
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. CQSpPQA
4、说明:子查询(表名1:a 表名2:b) -SvTg{Q{la
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) Q54r?|'V
5、说明:显示文章、提交人和最后回复时间 ';b3Mm
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Z cm<Fw
6、说明:外连接查询(表名1:a 表名2:b) \L ]
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c CZyz;Jtk
7、说明:在线视图查询(表名1:a ) n5v'
select * from (SELECT a,b,c FROM a) T where t.a > 1; lMC{SfdH
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 cq,v1Y<
select * from table1 where time between time1 and time2 382*
select a,b,c, from table1 where a not between 数值1 and 数值2 F!gNt<fZ
9、说明:in 的使用方法 Dn_"B0$lk
select * from table1 where a [not] in ('值1','值2','值4','值6') 2~!R*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 R<;OEN
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) x6^l6 N
11、说明:四表联查问题: tlV &eN
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 ..... D0/DI
12、说明:日程安排提前五分钟提醒 dn ZzA
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 S9G+#[.|
13、说明:一条sql 语句搞定数据库分页 ^kn^CI6
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 s.y q}Q
14、说明:前10条记录 (*6m^
select top 10 * form table1 where 范围 p^1zIC>F
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.) PS=e\(6QC
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #wenX$UTh3
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 UvxSMD:A
(select a from tableA ) except (select a from tableB) except (select a from tableC) V1SqX:;b&
17、说明:随机取出10条数据 >ZT& `E
select top 10 * from tablename order by newid() OM.k?1%+M
18、说明:随机选择记录 y?pD(u
select newid() o"p^/'ri
19、说明:删除重复记录 c,y|c`T 2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %MJL5
20、说明:列出数据库里所有的表名 bLgL0}=n
select name from sysobjects where type='U' YijMF/Uyb
21、说明:列出表里的所有的 S&4+ e:K
select name from syscolumns where id=object_id('TableName') /!3ZW XY\
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。
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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 mn]-rTr
显示结果: $Y6I_U
type vender pcs {L@+(I
电脑 A 1 0K<x=-cCB
电脑 A 1 .,3Zj /
光盘 B 2 ^rv"o:lF
光盘 A 2 z %x7fe
手机 B 3 RU2c*q$^X
手机 C 3 xvU]jl6d
23、说明:初始化表table1 d0(Cn}m"c
TRUNCATE TABLE table1 mxQR4"]jY
24、说明:选择从10到15的记录 c$0_R;4/
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc P+<BOG|m
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三、技巧 Sd},_Kh
1、1=1,1=2的使用,在SQL语句组合时用的较多 /X4yB"J>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, zfhTc=(/
如: .K IVf8)"
if @strWhere !='' =/FF1jQ
begin gH %y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere w
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end \6sqyWI
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else zZ%DtxUoU.
begin }A]BpSEP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' D+Cm<ZT~
end 5h0>!0
我们可以直接写成 ^[k0k(_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 3{"byfO#%
2、收缩数据库 IU@_)I+6
--重建索引 ?d$"[lKX
DBCC REINDEX E\0X`QeY
DBCC INDEXDEFRAG ?O??cjiA@
--收缩数据和日志 }g`Gh|C
DBCC SHRINKDB 8L%M<JRg~
DBCC SHRINKFILE -hWC_X:9jP
3、压缩数据库 Y\xUT>(J7
dbcc shrinkdatabase(dbname) x?"#gK`3;
4、转移数据库给新用户以已存在用户权限 nnNv0?>d(
exec sp_change_users_login 'update_one','newname','oldname' V!4a*,Pz
go l&Z
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5、检查备份集 f/}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 1,,|MW
6、修复数据库 %}q.cV
ALTER DATABASE [dvbbs] SET SINGLE_USER Z%}4bJ
GO n`(~OO
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8eluO ?p
GO t9FDU
ALTER DATABASE [dvbbs] SET MULTI_USER fc@'9-pt
GO ~,"N[Q
7、日志清除 0VN7/=n|
SET NOCOUNT ON 6;o3sf@Tf
DECLARE @LogicalFileName sysname, X\Y}oa."A
@MaxMinutes INT, y,E.SB
@NewSize INT P7:d ly[,q
USE tablename -- 要操作的数据库名 ~6`iY@)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~i ,"87$[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ^T6S()G
@NewSize = 1 -- 你想设定的日志文件的大小(M) gbDX7r-
-- Setup / initialize b9~A-Z
DECLARE @OriginalSize int K R, z^9
SELECT @OriginalSize = size <8!
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FROM sysfiles 1l5JP|x
WHERE name = @LogicalFileName %{!R
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + !^w
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
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FROM sysfiles s$w;q\1z
WHERE name = @LogicalFileName !E2W\chi
CREATE TABLE DummyTrans [Wi1|]X"G
(DummyColumn char (8000) not null) &xXEnV
DECLARE @Counter INT, Io n~
@StartTime DATETIME, ml6u1+v5
@TruncLog VARCHAR(255) D:"{g|nW}
SELECT @StartTime = GETDATE(), jZteooJG|
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' V`kMCE;?l
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o*5U:'=5}
EXEC (@TruncLog) t$J.+} }I
-- Wrap the log if necessary. OhVs#^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired nhT-Ido
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) jQ\zG J3
AND (@OriginalSize * 8 /1024) > @NewSize ]p7jhd=
BEGIN -- Outer loop. t)f-mQz)
SELECT @Counter = 0 ,ho3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) )G~w[~
BEGIN -- update {pL+2%`~
INSERT DummyTrans VALUES ('Fill Log') _n;;][]S
DELETE DummyTrans `R"~v/x
SELECT @Counter = @Counter + 1 a5YIUVCv
END rHjq1-t
EXEC (@TruncLog) ?t](a:IX
END up>c$jJ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Hc^W%t~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *v
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' CVNj-&vj
FROM sysfiles 3"N)xO-
WHERE name = @LogicalFileName 7aV%=_
DROP TABLE DummyTrans qpIC{'A.
SET NOCOUNT OFF M_g?<rK
8、说明:更改某个表 SAYLG
exec sp_changeobjectowner 'tablename','dbo' |`Or'%|PR
9、存储更改全部表 z2_6??tS/c
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch km~Ll
@OldOwner as NVARCHAR(128), ;X*cCb`h
@NewOwner as NVARCHAR(128) "&/-N[is
AS <sK4#!K
DECLARE @Name as NVARCHAR(128) >leU:7
DECLARE @Owner as NVARCHAR(128) 4=<tWa|@9
DECLARE @OwnerName as NVARCHAR(128) 1`ayc|9BR
DECLARE curObject CURSOR FOR q$I:`&
select 'Name' = name, hn#1%p6t
'Owner' = user_name(uid) q`-;AG|xF
from sysobjects (x/k.&
where user_name(uid)=@OldOwner =UUU$hq2
order by name ,]bB9tid
OPEN curObject [!!Q,S"
FETCH NEXT FROM curObject INTO @Name, @Owner rj(T~d4
WHILE(@@FETCH_STATUS=0) }gJ (DbnV
BEGIN 93Co}@Y;Y+
if @Owner=@OldOwner h1'\:N`
begin pe^u$YE
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ns6(cJ^a
exec sp_changeobjectowner @OwnerName, @NewOwner xJ#d1[kzo
end J8mdoVt
-- select @name,@NewOwner,@OldOwner SkmT`*v@
FETCH NEXT FROM curObject INTO @Name, @Owner :POj6j/
END `BlI@6th
close curObject x)( |[
deallocate curObject ep)>X@t
GO bv&;R
10、SQL SERVER中直接循环写入数据 n2iJ%_zp
declare @i int ty8v
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set @i=1 ")d`dj\o
while @i<30 d_IAs
begin &mb{.=
insert into test (userid) values(@i) Y "/]|'p
set @i=@i+1 ~ 4kc/a
end #B4%|v;`E?
小记存储过程中经常用到的本周,本月,本年函数 T}8Y6N<\m
Dateadd(wk,datediff(wk,0,getdate()),-1) 6i1LjLB
Dateadd(wk,datediff(wk,0,getdate()),6) #Y$hNQQ$F
Dateadd(mm,datediff(mm,0,getdate()),0) C.FI~Z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) gLOEh6
Dateadd(yy,datediff(yy,0,getdate()),0) oH_;4QU4y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V$ps>
上面的SQL代码只是一个时间段 @)fd}tV
Dateadd(wk,datediff(wk,0,getdate()),-1) ;qm
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Dateadd(wk,datediff(wk,0,getdate()),6) ,^C--tgZJg
就是表示本周时间段. EM[WK+9>I{
下面的SQL的条件部分,就是查询时间段在本周范围内的: /Njd[=B
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) `\}v#2VJ
而在存储过程中 0N$v"uX@
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) #w' kV#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) zzX_q(:S