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。 3mnq=.<(w
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一、基础 ]OKs65
1、说明:创建数据库 vo_m$ /O
CREATE DATABASE database-name PI0[
2、说明:删除数据库 e8"?Qm7 J
drop database dbname GY%48}7
3、说明:备份sql server G&/RJLX|w
--- 创建 备份数据的 device >>C(y?g
USE master HO(9)sK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^q0Ox&X
--- 开始 备份 $pm5G} .
BACKUP DATABASE pubs TO testBack Z@I.socA
4、说明:创建新表 T};fy+iq
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) E#=slj@
根据已有的表创建新表: r!vSYgee
A:create table tab_new like tab_old (使用旧表创建新表) ;8
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B:create table tab_new as select col1,col2... from tab_old definition only 7TjK;w7xS.
5、说明:删除新表 7#BpGQJQ
drop table tabname wZA(><\
6、说明:增加一个列 "`AIU}[_I
Alter table tabname add column col type )0I;+9:D=
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。 '8 ~E
7、说明:添加主键: Alter table tabname add primary key(col) 71?>~PnbH}
说明:删除主键: Alter table tabname drop primary key(col) <ZV !fn
8、说明:创建索引:create [unique] index idxname on tabname(col....) :3# t;
删除索引:drop index idxname \)pT+QxZ
注:索引是不可更改的,想更改必须删除重新建。 H1FSN6'
9、说明:创建视图:create view viewname as select statement /~Q2SrYH
删除视图:drop view viewname yI 6AafS~
10、说明:几个简单的基本的sql语句 W c"f
选择:select * from table1 where 范围 U`es
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插入:insert into table1(field1,field2) values(value1,value2) ( &U8NeWZ
删除:delete from table1 where 范围 {Y! -]_5
更新:update table1 set field1=value1 where 范围 k]=Yi;
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $6a55~h|(
排序:select * from table1 order by field1,field2 [desc] =sk]/64h``
总数:select count as totalcount from table1 u^T{sQ"_
求和:select sum(field1) as sumvalue from table1 OJUH".o
平均:select avg(field1) as avgvalue from table1 jc|"wN]
最大:select max(field1) as maxvalue from table1 :N<ZO`l?
最小:select min(field1) as minvalue from table1 7Xu.z9y
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11、说明:几个高级查询运算词 C"I:^&sL
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A: UNION 运算符 0#
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 p<\yp<g
B: EXCEPT 运算符 `4&
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 (0Xgv3wd
C: INTERSECT 运算符 U!L<v!$
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。 3sf+u oV
注:使用运算词的几个查询结果行必须是一致的。 >900O4
12、说明:使用外连接 !'()QtvC<
A、left outer join: P%v7(bqL4+
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。 e{~s\G8g
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 VQ/<MY C
B:right outer join: |.x |BJ
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。 ;=IGl:
C:full outer join: zice0({iJ
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。 fD#VI
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二、提升 5sD\4 g)HK
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) h^h!OQK Q
法一:select * into b from a where 1<>1 |RBgJkS;8
法二:select top 0 * into b from a .6yC' 3~;o
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jj,Y:
insert into b(a, b, c) select d,e,f from b; FfnW
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) 5fK#*(x
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Y!C=0&p
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. xA DjQ%B
4、说明:子查询(表名1:a 表名2:b) -,t2D/xK
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) Q
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5、说明:显示文章、提交人和最后回复时间 oGi;S ="I
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~G!>2 +L
6、说明:外连接查询(表名1:a 表名2:b) F^Yt\V~T
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 15i8) 4h
7、说明:在线视图查询(表名1:a ) f>Mg.9gJ(
select * from (SELECT a,b,c FROM a) T where t.a > 1; 51Yq>'8
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 0^VA,QkQ\
select * from table1 where time between time1 and time2 5+<<:5_6l
select a,b,c, from table1 where a not between 数值1 and 数值2 Zb)j2Xgl
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') $okGqu8z.O
10、说明:两张关联表,删除主表中已经在副表中没有的信息 "=0#pH1o
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Y4Hi<JWo
11、说明:四表联查问题: n%lY7.z8d
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... _u$X.5Q;
12、说明:日程安排提前五分钟提醒 io_4d2uBh
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 d>z?JDt
13、说明:一条sql 语句搞定数据库分页 =6Dz<Lq
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 Z[Gs/D
14、说明:前10条记录 1/>#L6VAZ
select top 10 * form table1 where 范围 IT a8*Myj
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.) _C3l2v'I$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) P>/n!1c
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 >E&mNp
(select a from tableA ) except (select a from tableB) except (select a from tableC) P%hi*0pwZ
17、说明:随机取出10条数据 U$j*{`$4
select top 10 * from tablename order by newid() W8:?y*6
18、说明:随机选择记录 iq> PN:mr
select newid() ?:(BkY,K5
19、说明:删除重复记录 SG1fu<Q6J
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) t&+f:)n
20、说明:列出数据库里所有的表名 "oX@Z^
select name from sysobjects where type='U' Hf( d x\5
21、说明:列出表里的所有的 _Y'+E
select name from syscolumns where id=object_id('TableName') #!d@;=[\
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 #M;Cw}pW
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 0GW(?7ZC
显示结果: -,NiSh}A
type vender pcs 1s4+a^&
电脑 A 1 u9Wi@sO#
电脑 A 1 4-@D` ,3L
光盘 B 2 Z `FqC
光盘 A 2 9H~3&-8&
手机 B 3 LMchNTL
手机 C 3 0?3Ztdlb
23、说明:初始化表table1 >'4Bq*5>
TRUNCATE TABLE table1 Ur`Ri?
24、说明:选择从10到15的记录 kH
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [U_Su,
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三、技巧 Fw!CssW
1、1=1,1=2的使用,在SQL语句组合时用的较多 (P
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ay'2!K,I
如: +$Q33@F5l
if @strWhere !='' RX.n7Tb
begin hC@oyC(4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere SsiKuoxk
end =}txcA+
else juPW!u
begin 5#+G7 'k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' g6:S"Em
end G"3)\FEM
我们可以直接写成 x{IxS?.j+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Z)cGe1?q
2、收缩数据库 gR)T(%W
--重建索引 _idTsd:\
DBCC REINDEX O-r,&W
DBCC INDEXDEFRAG FBpf_=(_1
--收缩数据和日志 Nq|b$S [4
DBCC SHRINKDB 6T>e~<^
DBCC SHRINKFILE f8u m.Xnp6
3、压缩数据库 PzThVeJ+
dbcc shrinkdatabase(dbname) a= *&OW
4、转移数据库给新用户以已存在用户权限 #% PnZ
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exec sp_change_users_login 'update_one','newname','oldname' V=}AFGC85
go )8Defuxk
5、检查备份集 +~lZ]a7k
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Y>*{(QD
6、修复数据库 ?5d7J,"<h
ALTER DATABASE [dvbbs] SET SINGLE_USER IHCEuK
GO %;+Q0
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o@6:|X)7
GO i;!#:JX
ALTER DATABASE [dvbbs] SET MULTI_USER 7Pu.<b}
GO
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7、日志清除 q~9Y&>D
SET NOCOUNT ON y'ULhDgq^B
DECLARE @LogicalFileName sysname, DDh$n?2fd
@MaxMinutes INT, QEIu}e6b
@NewSize INT _MfXN$I?}
USE tablename -- 要操作的数据库名 g+Z~"O]$M
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &Pu}"M$[MH
@MaxMinutes = 10, -- Limit on time allowed to wrap log. _]W
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@NewSize = 1 -- 你想设定的日志文件的大小(M) Ar4@7
-- Setup / initialize Z)B5g>
DECLARE @OriginalSize int {U?UM
SELECT @OriginalSize = size R(Y4n w+Y-
FROM sysfiles Jybx'vZj
WHERE name = @LogicalFileName >(Mu9ie*`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bgs2~50
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,zmGKn#n2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z7X[$T$V
FROM sysfiles dZ'hTzw~
WHERE name = @LogicalFileName _&s37A&\
CREATE TABLE DummyTrans ni$7)YcF
(DummyColumn char (8000) not null) `4E6&&E+S
DECLARE @Counter INT, ^s<p5V
@StartTime DATETIME, ,gHgb
@TruncLog VARCHAR(255) Tdvw7I-q
SELECT @StartTime = GETDATE(), 6@_Vg~=S
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' g:bw;6^u
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0KknsP7
EXEC (@TruncLog) W#1t%hT$
-- Wrap the log if necessary. n~xh
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /(-X[[V
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) qI,4uGg
AND (@OriginalSize * 8 /1024) > @NewSize }{<@wE%s
BEGIN -- Outer loop. Ba-Ftkb
SELECT @Counter = 0 ts rcX
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C]{:>= K
BEGIN -- update r9@4-U7v&
INSERT DummyTrans VALUES ('Fill Log') xB=~3
DELETE DummyTrans oW]~\vp^0
SELECT @Counter = @Counter + 1 ^3*k6h[(
END OEc$ro=m*
EXEC (@TruncLog) :n36}VG|
END >% a^;gk(
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Z3Le?cMt^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |1vikG8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 67zCil
FROM sysfiles cY1d6P0
WHERE name = @LogicalFileName H% c:f
DROP TABLE DummyTrans D&KD5_Sw
SET NOCOUNT OFF Z~O1$,Z
8、说明:更改某个表 Aa^%_5
exec sp_changeobjectowner 'tablename','dbo' '{9nQDgT
9、存储更改全部表 1muB*
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 9L+dN%C
@OldOwner as NVARCHAR(128), z&!n'N<C
@NewOwner as NVARCHAR(128) (9bFIvMc
AS bL>J0LWQ
DECLARE @Name as NVARCHAR(128) k!Y7Rc{"
DECLARE @Owner as NVARCHAR(128) *,Bo $:(n
DECLARE @OwnerName as NVARCHAR(128) zX+NhTTB
DECLARE curObject CURSOR FOR [43:E*\$
select 'Name' = name, 8RC7Ei
'Owner' = user_name(uid) rOC2 S(m
from sysobjects OmO/x
where user_name(uid)=@OldOwner 9Yg=4>#$
order by name 3=(Gb
OPEN curObject Si[:l
FETCH NEXT FROM curObject INTO @Name, @Owner FF]xwptrx
WHILE(@@FETCH_STATUS=0) ]mEY/)~7
BEGIN MpZ
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if @Owner=@OldOwner 5v:c@n
begin l*;Isz:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) V@6,\1#`|
exec sp_changeobjectowner @OwnerName, @NewOwner P9j[
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end 8.9TWsZ
-- select @name,@NewOwner,@OldOwner ,U9gg-.Lp
FETCH NEXT FROM curObject INTO @Name, @Owner 0Q]@T@F.
END eq)8V x0
close curObject md8r"
deallocate curObject %hcn|-"F
GO : ]&O