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。 'mH9O
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一、基础 ZW6ZO[`6
1、说明:创建数据库 efK|)_i
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CREATE DATABASE database-name }bW"Z2^nB
2、说明:删除数据库 Jvk!a~e
drop database dbname 3XCePA5z
3、说明:备份sql server L=ala1{O
--- 创建 备份数据的 device 2=&4@c|cn
USE master AB!P(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' C6$F.v
--- 开始 备份 ^9{mjy0Q
BACKUP DATABASE pubs TO testBack vS!%!-F
4、说明:创建新表 &.>
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) CSUXa8u7
根据已有的表创建新表: LSR{N|h+)
A:create table tab_new like tab_old (使用旧表创建新表) EH*Lw
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B:create table tab_new as select col1,col2... from tab_old definition only 3X0"</G6
5、说明:删除新表 yXuF<+CJ
drop table tabname 0Y%u[i/
6、说明:增加一个列 j~|pSu.<
Alter table tabname add column col type .4jU G=
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 BrWo/1b
7、说明:添加主键: Alter table tabname add primary key(col) #6'x-Z_
说明:删除主键: Alter table tabname drop primary key(col) KA=cIm
8、说明:创建索引:create [unique] index idxname on tabname(col....) M<4tjVQ6
删除索引:drop index idxname b,Z\{M:f;F
注:索引是不可更改的,想更改必须删除重新建。 20Umjw.D
9、说明:创建视图:create view viewname as select statement TqvgCk-
删除视图:drop view viewname gPo3jw o$
10、说明:几个简单的基本的sql语句 r )EuH.z
选择:select * from table1 where 范围 aBBTcN%'
插入:insert into table1(field1,field2) values(value1,value2) @v#]+9F
删除:delete from table1 where 范围 TA2?Ia;@xV
更新:update table1 set field1=value1 where 范围 gc
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 3gUGfedi
排序:select * from table1 order by field1,field2 [desc] "kS(b4^
总数:select count as totalcount from table1 Lrr1) h
求和:select sum(field1) as sumvalue from table1 ^an3&
平均:select avg(field1) as avgvalue from table1 ^}F @*A;o
最大:select max(field1) as maxvalue from table1 4axc05
最小:select min(field1) as minvalue from table1 4
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11、说明:几个高级查询运算词 9d\B*OU
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A: UNION 运算符 <b5J"i&m
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。 m(CbMu
B: EXCEPT 运算符 yV'<l
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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。 6r|Bi HP
C: INTERSECT 运算符 wDL dmrB
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。 |uT&M`7\{
注:使用运算词的几个查询结果行必须是一致的。 _ ?\4k{ET
12、说明:使用外连接 K+`$*vS~ws
A、left outer join: @CxXkR
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。 *c0\<BI
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 $bGe1\
B:right outer join: Fz3QSr7FU
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。 cAL*Md8+
C:full outer join: MFHc>O
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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。 K|OowM4tv
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二、提升 ,{pC1A@s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6F@2:]W
法一:select * into b from a where 1<>1 Q9[$8
法二:select top 0 * into b from a "G(^v?x:P
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;&A%"8o
insert into b(a, b, c) select d,e,f from b; Q9\6Pn ]T
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Wg V'T#*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 No'^]r
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. T##_?=22I
4、说明:子查询(表名1:a 表名2:b) -f4>4@y
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) #nzVgV]
5、说明:显示文章、提交人和最后回复时间 =LUDg7P
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b TqZ&X|G
6、说明:外连接查询(表名1:a 表名2:b) Uc?4!{$X
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c PXH"%vVF
7、说明:在线视图查询(表名1:a ) r=`]L-}V
select * from (SELECT a,b,c FROM a) T where t.a > 1; z .xOT;t
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 !Q0aKkMfL
select * from table1 where time between time1 and time2 h/AL`$
select a,b,c, from table1 where a not between 数值1 and 数值2 #Is/j =
9、说明:in 的使用方法 :We}l;.jQ
select * from table1 where a [not] in ('值1','值2','值4','值6') 2".^Ma^D!
10、说明:两张关联表,删除主表中已经在副表中没有的信息 V*|#j0}b
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %"1*,g{
11、说明:四表联查问题: L,
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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 ..... ?9?eA^X%
12、说明:日程安排提前五分钟提醒 .2si[:_(p
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 9AbSt&#
13、说明:一条sql 语句搞定数据库分页 (t{m(;/
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 0D\b;ju<
14、说明:前10条记录 7Lv5@
select top 10 * form table1 where 范围 5z$>M3
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.) 5 GwXZ;(G
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ,z*-93H1
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 +mr\AAFn
(select a from tableA ) except (select a from tableB) except (select a from tableC) [T5z}!_y
17、说明:随机取出10条数据 ~I+}u]J
select top 10 * from tablename order by newid() ;M95A
18、说明:随机选择记录 w^.^XK4v.
select newid() 8" x+^
19、说明:删除重复记录 -d|VXD5N
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) -9.Rmv#og{
20、说明:列出数据库里所有的表名 :=0XT`iY
select name from sysobjects where type='U' wl*"Vagb
21、说明:列出表里的所有的 uAWmg8
select name from syscolumns where id=object_id('TableName') 0%m}tfQ5
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。 @rTAbEk{U
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 \mBH6GS
显示结果: dZ
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type vender pcs \[-z4Fxg|'
电脑 A 1 s`bC?wr5h
电脑 A 1 49BLJ|:P?
光盘 B 2 `$X|VAS2
光盘 A 2 >/kwy2
手机 B 3 T%Vg0Y)P;
手机 C 3 w84
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23、说明:初始化表table1 Z1(-FT6O
TRUNCATE TABLE table1 PR&D67:Jy
24、说明:选择从10到15的记录 )LA^j|Y}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Qe~2'Hw#9
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三、技巧 ~okIiC]#
1、1=1,1=2的使用,在SQL语句组合时用的较多 `%2e?"OOJ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, h-XMr_F
如: pearf2F
if @strWhere !='' XZcT-w7
begin U#B,Q6~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $Qm-p?f
end a?+Ni|+
else S;o U'KOY
begin Kb_R "b3v
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' cU y,q]PO
end 3X+uJb2
我们可以直接写成 ,RkL|'1l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere b&$ ?.z
2、收缩数据库 >.D0McQg
--重建索引 mGQgy[gX
DBCC REINDEX BO5gwvyI
DBCC INDEXDEFRAG XFeeNcqF
--收缩数据和日志 ."m6zq
DBCC SHRINKDB iL-I#"qT,
DBCC SHRINKFILE E)Z$7;N0x
3、压缩数据库 zS Yh ?NB5
dbcc shrinkdatabase(dbname) :!a9|Fh~
4、转移数据库给新用户以已存在用户权限 Yx_[vLm
exec sp_change_users_login 'update_one','newname','oldname' H=vrF - #
go B|IQ/g?
5、检查备份集 UarU.~Uqi
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' U~8.uldnF
6、修复数据库 k_9tz}Z
ALTER DATABASE [dvbbs] SET SINGLE_USER &bx;GG\<4
GO -aiQp@^/J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A9!gww
GO \lK iUy/
ALTER DATABASE [dvbbs] SET MULTI_USER khl(9R4a
GO H/_R!G8\
7、日志清除 d 7A08l{
SET NOCOUNT ON &XosDt
DECLARE @LogicalFileName sysname, lz!F{mR
@MaxMinutes INT, }DTpl?l
@NewSize INT 0&U,WA
USE tablename -- 要操作的数据库名 4BG6C'`%
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z*d8b
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \#5t%t
@NewSize = 1 -- 你想设定的日志文件的大小(M) L!E/ )#{
-- Setup / initialize &\] [:kG;
DECLARE @OriginalSize int oK h#th
SELECT @OriginalSize = size /"?y @;Y~
FROM sysfiles d"+zDc;
WHERE name = @LogicalFileName B]< 6\Z?=
SELECT 'Original Size of ' + db_name() + ' LOG is ' + r)<]W@Pr
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8uoFV=bj\
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' p(MhDS\J
FROM sysfiles eL9RrSXz
WHERE name = @LogicalFileName >_U)=q
CREATE TABLE DummyTrans (US]e
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(DummyColumn char (8000) not null) KO(+%>^R
DECLARE @Counter INT, )t{oyBT
@StartTime DATETIME, SMaC{RPQ
@TruncLog VARCHAR(255) CjM+%l0MW
SELECT @StartTime = GETDATE(), 2O {@W +Mt
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1oaiA/bq
DBCC SHRINKFILE (@LogicalFileName, @NewSize) vV1F|
EXEC (@TruncLog) 9Y1&SEsNX
-- Wrap the log if necessary. Q44Pg$jp
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired d$s1l
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) WO$PW`k
AND (@OriginalSize * 8 /1024) > @NewSize o|8
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BEGIN -- Outer loop. 4EzmH)4G
SELECT @Counter = 0 s
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) K1Nhz'^=D
BEGIN -- update *52*IRH
INSERT DummyTrans VALUES ('Fill Log') 6%NX|4_
DELETE DummyTrans R8UtX9'*sa
SELECT @Counter = @Counter + 1 Eom|*2vWIC
END V'~]b~R
EXEC (@TruncLog) dg 0`0k
END km'3[}8o&
SELECT 'Final Size of ' + db_name() + ' LOG is ' + VO>A+vx3M
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + &^4\Rx_I
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' A] pLq`
FROM sysfiles xh[Mmq/R
WHERE name = @LogicalFileName Z}.N4 /
DROP TABLE DummyTrans ]y@8mb&
SET NOCOUNT OFF zu<b#W v
8、说明:更改某个表 5+b[-Daz
exec sp_changeobjectowner 'tablename','dbo' #gi0FXL
9、存储更改全部表 $"C]y$}
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )I{41/_YA
@OldOwner as NVARCHAR(128), oabc=N!7r
@NewOwner as NVARCHAR(128) 4&)*PKq
AS
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DECLARE @Name as NVARCHAR(128) O^|dc=
DECLARE @Owner as NVARCHAR(128) fM?HZKo
DECLARE @OwnerName as NVARCHAR(128) oAe]/ j$
DECLARE curObject CURSOR FOR Ojq>4=Z\
select 'Name' = name, n[lf==R
'Owner' = user_name(uid) Y8`4K* 58%
from sysobjects E~ _2Jf\U
where user_name(uid)=@OldOwner cjsQm6
order by name [Rw0']i`4
OPEN curObject 1Vt7[L*
FETCH NEXT FROM curObject INTO @Name, @Owner Oga0CR_
WHILE(@@FETCH_STATUS=0) Bvzl*
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BEGIN (%"M% Qko
if @Owner=@OldOwner [ jve
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begin 7kO5hlKeo
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2Ch!LS:+
exec sp_changeobjectowner @OwnerName, @NewOwner L=3^A'|
end G`PSb<h\oc
-- select @name,@NewOwner,@OldOwner /4+M0P l
FETCH NEXT FROM curObject INTO @Name, @Owner 1w'iD
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END OEy'8O$
close curObject 1.!rq,+>1
deallocate curObject v5i[jM8
GO !=--pb
10、SQL SERVER中直接循环写入数据 &K2[>5
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declare @i int 5:E7nqsNhq
set @i=1 c 6@!?8J
while @i<30 HS.3PE0^C
begin xz[a3In+
insert into test (userid) values(@i) dQ@e+u5
set @i=@i+1 YUJlQ2e(
end Kc_QxON4
小记存储过程中经常用到的本周,本月,本年函数 (p26TN;*$5
Dateadd(wk,datediff(wk,0,getdate()),-1) .]0B=w* Z
Dateadd(wk,datediff(wk,0,getdate()),6) yd[}?
Dateadd(mm,datediff(mm,0,getdate()),0) )VQ:L:1t(
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) RxU6.5N
Dateadd(yy,datediff(yy,0,getdate()),0) J!O5`k*.C
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) T5.1qr L
上面的SQL代码只是一个时间段 % @3AA<
Dateadd(wk,datediff(wk,0,getdate()),-1) Q]Q i
Dateadd(wk,datediff(wk,0,getdate()),6) qY`)W[
就是表示本周时间段. &F9BaJ
下面的SQL的条件部分,就是查询时间段在本周范围内的: 1s8 v E
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) VI0^Zq!6R
而在存储过程中 )Y}t~ Zfx
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %s P C3L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) FFb`4.