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。 U~CG(9
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一、基础 )t#>fnN
1、说明:创建数据库 qX9x#92
CREATE DATABASE database-name L.ML0H-
2、说明:删除数据库 ^WF/gup\hS
drop database dbname 4
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3、说明:备份sql server {u}d`%_.M
--- 创建 备份数据的 device ]&b>P ;j:
USE master u=QG%O#B
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' {)`tN&\
--- 开始 备份 57|RE5]|!
BACKUP DATABASE pubs TO testBack 1ze\ U>
4、说明:创建新表 }+@GgipyO.
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kO3N.t@n
根据已有的表创建新表: x&
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A:create table tab_new like tab_old (使用旧表创建新表) X;/5Niv32q
B:create table tab_new as select col1,col2... from tab_old definition only e0Jz|?d=
5、说明:删除新表 E\Qm09Dj`<
drop table tabname n9H4~[JiC
6、说明:增加一个列 ITssBB9
Alter table tabname add column col type 'g5 Gdn
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。 Dve+ #H6N
7、说明:添加主键: Alter table tabname add primary key(col) )lhPl
说明:删除主键: Alter table tabname drop primary key(col) #@UzOQ>
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^{}$o#iof
删除索引:drop index idxname vk><S|[n
注:索引是不可更改的,想更改必须删除重新建。 Mn<#rBE B
9、说明:创建视图:create view viewname as select statement R3bHX%T
删除视图:drop view viewname "/kTEp
10、说明:几个简单的基本的sql语句 w}rsboU
选择:select * from table1 where 范围 <*Bk.>f!
插入:insert into table1(field1,field2) values(value1,value2) af-
删除:delete from table1 where 范围 a(#aEbN?d
更新:update table1 set field1=value1 where 范围 x=I|O;"><
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F1A7l"X]
排序:select * from table1 order by field1,field2 [desc] CT0 ~
总数:select count as totalcount from table1 w7E7r?)Wl|
求和:select sum(field1) as sumvalue from table1 WU+OS(
平均:select avg(field1) as avgvalue from table1 k.n-JS
最大:select max(field1) as maxvalue from table1 }lQ`ka
最小:select min(field1) as minvalue from table1 $S'~UbmYU
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11、说明:几个高级查询运算词 +1pY^#A
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A: UNION 运算符 BG9.h!
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 `JAM]qB"
B: EXCEPT 运算符 X/qLg+X
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 "i^<
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C: INTERSECT 运算符 Dt~ |)L+
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 s&)>gE\
注:使用运算词的几个查询结果行必须是一致的。 i_{b*o_an
12、说明:使用外连接 %0Mvd;#[
A、left outer join: pd\x^F`sk.
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 |*5HNP
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c efrVF5,y?
B:right outer join: L ]Y6/Q
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Z=.$mFE\
C:full outer join: yt[vd8O'c
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。 8`B]UcL)
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二、提升 p0sq{d~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o>jM4sk$
法一:select * into b from a where 1<>1 c( 8>|^M
法二:select top 0 * into b from a ?}ly`Js
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "CY#_)
insert into b(a, b, c) select d,e,f from b; _Squ%z:D
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) b-OniMq~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 w#!b #TNc
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. =im7RgIBo
4、说明:子查询(表名1:a 表名2:b) J ?^R1
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) xcM*D3
5、说明:显示文章、提交人和最后回复时间 6d{&1-@>
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (iJ9ekB
6、说明:外连接查询(表名1:a 表名2:b) xe@11/F
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Vo`,|3^
7、说明:在线视图查询(表名1:a ) 8Cef ]@x
select * from (SELECT a,b,c FROM a) T where t.a > 1; E(-@F%Q
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 "n%0L4J
select * from table1 where time between time1 and time2 Ql]+,^kA@
select a,b,c, from table1 where a not between 数值1 and 数值2 ~]V}wZt>h
9、说明:in 的使用方法 8nE}RD7bx
select * from table1 where a [not] in ('值1','值2','值4','值6') :lE_hY
10、说明:两张关联表,删除主表中已经在副表中没有的信息 $I|6v
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) UfSqiu
11、说明:四表联查问题: U#6<80Ke
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 ..... }8eu 9~
12、说明:日程安排提前五分钟提醒 {?RVw`g&f
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 R5& R~1N
13、说明:一条sql 语句搞定数据库分页 6DT^:LHS
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 <5E: ,<
14、说明:前10条记录 z)F<{]%
select top 10 * form table1 where 范围 RAU"
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.) A+41JMH
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c-oIP~,
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 py }`thx
(select a from tableA ) except (select a from tableB) except (select a from tableC) >_|$7m.?n[
17、说明:随机取出10条数据 4GqwY"ja
select top 10 * from tablename order by newid() ?:DUsg
18、说明:随机选择记录 d:8c}t2X
select newid() ^_c6Op<F
19、说明:删除重复记录 #p7K2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) N%Uk/ c'
20、说明:列出数据库里所有的表名 n^iq?u
select name from sysobjects where type='U' y
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21、说明:列出表里的所有的 rsn^YC
select name from syscolumns where id=object_id('TableName') LTw.w:"J
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。 "I,=L;p
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 Xrr3KQaK&
显示结果: H&SoVi_V
type vender pcs o2rL&
电脑 A 1 u"gtv
电脑 A 1 A-f,&TO
光盘 B 2 Sp/<%+2(
光盘 A 2 h>"j!|#!s
手机 B 3 2Y~nU(
手机 C 3 EE5mVC&
23、说明:初始化表table1 vHXCT?FuG
TRUNCATE TABLE table1 -]Y@_T.C
24、说明:选择从10到15的记录 3eERY[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc pD17r}%
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三、技巧 Vrn+"2pdJ
1、1=1,1=2的使用,在SQL语句组合时用的较多 ib- H
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, !2F X l;
如: %R^*MUTx
if @strWhere !='' .]YTS
begin 7q(A&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere a.2Xl}2o5
end =/Ph]f9
else IXv9mr?H}
begin A)_HSIVi
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i]15g@
end _=_<cgy1u
我们可以直接写成 txik{' :
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7 T
2、收缩数据库 "A]#KTP
--重建索引 Y/ I32@
DBCC REINDEX Zo<j"FG
DBCC INDEXDEFRAG mtmTlGp6Lc
--收缩数据和日志 SS6K7
DBCC SHRINKDB $.x,[R
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DBCC SHRINKFILE Xp[x O 0
3、压缩数据库 [`kk<$=,&
dbcc shrinkdatabase(dbname) xF6byTi
4、转移数据库给新用户以已存在用户权限 /B<QYvv
exec sp_change_users_login 'update_one','newname','oldname' C}qHvwFm
go rXR!jZ.hi
5、检查备份集 \V#fl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' DY\~O
6、修复数据库 8.:WMH`
ALTER DATABASE [dvbbs] SET SINGLE_USER Y @Ur}
GO %-woaj
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK E[cH/Rm
GO r+k g$+%b
ALTER DATABASE [dvbbs] SET MULTI_USER rK\9#[?x
GO AsI\#wL)
7、日志清除 "hk {"0E
SET NOCOUNT ON K /$-H#;N
DECLARE @LogicalFileName sysname, YQcaWd(
@MaxMinutes INT, sYbmL`{
@NewSize INT /gn!="J
USE tablename -- 要操作的数据库名 nS](d2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 i5aY{3!
@MaxMinutes = 10, -- Limit on time allowed to wrap log. G@txX
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@NewSize = 1 -- 你想设定的日志文件的大小(M) ]$=#:uf
-- Setup / initialize x4K A8
DECLARE @OriginalSize int V8Ri2&|3
SELECT @OriginalSize = size c \;_jg
FROM sysfiles 1obajN
WHERE name = @LogicalFileName ~=Q^]y,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^YJ%^P
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + U;j\FE^+>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~+C)0Yn
FROM sysfiles YmCu\+u
WHERE name = @LogicalFileName GT<!e]=6
CREATE TABLE DummyTrans GVhy
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(DummyColumn char (8000) not null) k{H7+;_
DECLARE @Counter INT, {[3xi`0-
@StartTime DATETIME, e/&^~ $h
@TruncLog VARCHAR(255) E\ls- (,
SELECT @StartTime = GETDATE(), L5'?.9]
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' gD2P)7:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Q'Tg0,,S
EXEC (@TruncLog) '50}QY_R.
-- Wrap the log if necessary. ^HxIy;EQ<z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired I1Otu~%d
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %/ctt_p0x
AND (@OriginalSize * 8 /1024) > @NewSize B77`azwF
BEGIN -- Outer loop.
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SELECT @Counter = 0 D^gS.X ^
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) [X91nUz#
BEGIN -- update wh)F&@6 R!
INSERT DummyTrans VALUES ('Fill Log') Nv^byWqu
DELETE DummyTrans Ra"hdxH
SELECT @Counter = @Counter + 1 5YneoM]Q
END >7PNl\=gG
EXEC (@TruncLog) PW82
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END Au6Y]
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .)SR3?
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + CW2)1%1iz
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' =t`cHs29
FROM sysfiles `ZbFky{
WHERE name = @LogicalFileName !*f$*,=^
DROP TABLE DummyTrans QIg'js$W
SET NOCOUNT OFF C T\@>!'f
8、说明:更改某个表 ITg<u?z_
exec sp_changeobjectowner 'tablename','dbo' ~GcWG4
9、存储更改全部表 Cv}^]_`Q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch NWP!V@WG
@OldOwner as NVARCHAR(128), a{@}vZx>3
@NewOwner as NVARCHAR(128) |B^Mj57DO
AS uuxVVgWp{
DECLARE @Name as NVARCHAR(128) qXhdU/
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DECLARE @Owner as NVARCHAR(128) lB0`|UEb (
DECLARE @OwnerName as NVARCHAR(128) Rw|'LaW
DECLARE curObject CURSOR FOR 4v`IAR?&K;
select 'Name' = name, .!Pg)|
'Owner' = user_name(uid) #?V rt,n
from sysobjects NSBcYObX
where user_name(uid)=@OldOwner b]fx
order by name TDUY& 1[
OPEN curObject #q h
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FETCH NEXT FROM curObject INTO @Name, @Owner b\"w/'XX
WHILE(@@FETCH_STATUS=0) D$7#&2y
BEGIN !sSq 4K
if @Owner=@OldOwner :PtZKt;~X
begin ~USt&?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1Qu@pb^
exec sp_changeobjectowner @OwnerName, @NewOwner .r2*tB).
end 9Msy=qvYG
-- select @name,@NewOwner,@OldOwner z~ywFk}KGd
FETCH NEXT FROM curObject INTO @Name, @Owner <N1wET-
END B]@25
close curObject uKd4+Km
deallocate curObject L,[Q{:C S
GO OZ+v ~'oD
10、SQL SERVER中直接循环写入数据 +[<YE
declare @i int [:FiA?O]
set @i=1 a&V;^ /
while @i<30 g;v;xlY`N
begin fGO\f;P
insert into test (userid) values(@i) ;AE-=/<
set @i=@i+1 4(|yl^w
end A4'5cR9T!
小记存储过程中经常用到的本周,本月,本年函数 3+15
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Dateadd(wk,datediff(wk,0,getdate()),-1) !
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Dateadd(wk,datediff(wk,0,getdate()),6) 8AX_y3$
Dateadd(mm,datediff(mm,0,getdate()),0) :nQlS
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I O:*F0
Dateadd(yy,datediff(yy,0,getdate()),0) u '7h(1@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) IHYLM;@L
上面的SQL代码只是一个时间段 Ps74SoD-
Dateadd(wk,datediff(wk,0,getdate()),-1) BBRL_6
Dateadd(wk,datediff(wk,0,getdate()),6) Y}1c>5{bE
就是表示本周时间段. ;4[[T%&v
下面的SQL的条件部分,就是查询时间段在本周范围内的: xbm%+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]S%(l,
而在存储过程中 o87kF!x
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %VH, (}i
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) XTo7fbW*