SQL ѧϰ±Ê¼ÇÖ®SelectÍêÕûÓï·¨¼°Ö´Ðйý³ÌÏê½â
SELECTÓï¾äµÄÍêÕûÓ﷨Ϊ£º
SELECT[ALL|DISTINCT|DISTINCTROW|TOP]
{*|talbe.*|[table.]field1[AS alias1][,[table.]field2[AS alias2][,…]]}
from tableexpression[,…][IN externaldatabase]
[WHERE…]
[GROUP BY…]
[HAVING…]
[ORDER BY…]
[WITH OWNERACCESS OPTION]
×¢Òâ Where£¬GroupBy£¬Having£¬OrderBy ˳Ðò¡£
Ö´Ðв½Öè
1£©ÏÈ´Ófrom×Ö¾äÒ»¸ö±í»ò¶à¸ö±í´´½¨¹¤×÷±í
2£©½«whereÌõ¼þÓ¦ÓÃÓÚ1£©µÄ¹¤×÷±í£¬±£ÁôÂú×ãÌõ¼þµÄÐÐ
3£©GroupBy ½«2£©µÄ½á¹û·Ö³É¶à¸ö×é
4£©Having ½«Ìõ¼þÓ¦ÓÃÓÚ3£©×éºÏµÄÌõ¼þ¹ýÂË£¬Ö»±£Áô·ûºÏÒªÇóµÄ×é¡£
5£©Order By¶Ô½á¹û½øÐÐÅÅÐò¡£
ʹÓÃDISTINCTÈ¥³ýÖØ¸´µÄÐÅÏ¢
Ö´ÐУº
select * from student
·µ»Ø½á¹û
-stuName -stuno
Tom Sawyer 1
Andy Ke 2
Angelia Jolie 3
Celine Dion 4
alex 5
alex 6
Ö´ÐУº
select distinct stu_name from student
½á¹û£º
alex
Andy Ke
Angelia Jolie
Celine Dion
Tom Sawyer
¼´È¥µôÁËÖØ¸´Öµ£¬ÓÖ¶Ô²éѯ½á¹û½øÐÐÁËÅÅÐò¡£Êµ¼ÊÉÏDBMSµÄ²Ù×÷¹ý³ÌÊÇÏȶԲéѯ½á¹ûÅÅÐòÔÚ´Ó½á¹ûÖÐÈ¥³ýÖØ¸´µÄ
Ïà¹ØÎĵµ£º
--´´½¨Ð´ÎļþµÄ´æ´¢¹ý³Ì
ALTER proc [dbo].[p_movefile]
@filename varchar(1000),--Òª²Ù×÷µÄÎı¾ÎļþÃû
@text varchar(8000), --ҪдÈëµÄÄÚÈÝ
@obj int
as
begin
declare @err int,
@src varchar(255),
&n ......
SQL Server´´½¨ÁÙʱ±í£º
´´½¨ÁÙʱ±í
·½·¨Ò»£º
create table #ÁÙʱ±íÃû(×Ö¶Î1 Ô¼ÊøÌõ¼þ,
×Ö¶Î2 Ô¼ÊøÌõ¼þ,
.....)
create table ##ÁÙʱ±íÃû(×Ö¶Î1 Ô¼ÊøÌõ¼þ,
×Ö¶Î2 Ô¼ÊøÌõ¼þ,
.....)
·½·¨¶þ£º
select * into #ÁÙʱ±íÃû from ÄãµÄ±í;
select * into ##ÁÙʱ±íÃû from ÄãµÄ±í;
×¢£ºÒÔÉϵÄ#´ú±í¾Ö²¿ÁÙʱ±í£¬##´ú±íÈ«¾ ......
±¾ÎĽéÉÜÁËSQL Server 2005ÖÐÉÙÊýÈËÓõ½µÄÁ½Ìõ¾«Æ·ÐÂÓï·¨£¬´ó¼Ò¿´¿´×Ô¼ºÊÇ·ñÖªµÀÄØ……
¡¡¡¡1. OUTPUT ... INTO
¡¡¡¡ÓÃÓÚ½«Ò»Ìõ¼Ç¼´Ó±íÒ»ÒÆ¶¯µ½±í¶þʱ·Ç³£ºÃÓ㬳£¼ûÓÚ±¸·Ý¼Ç¼µÄÓ¦ÓÃ
¡¡¡¡ÀýÒ»£º
¡¡¡¡DELETE [TableUseing]
¡¡¡¡OUTPUT *
¡¡¡¡INTO [TableBak]
¡¡¡¡Àý¶þ£º(ÓÃÓÚÒÆ¶¯Ê±ÐÞ ......
¡¡ÈçºÎÔ¶³ÌÅжÏOracleÊý¾Ý¿âµÄ°²×°Æ½Ì¨
¡¡¡¡select * from v$version;
¡¡¡¡²é¿´±í¿Õ¼äµÄʹÓÃÇé¿ö
¡¡¡¡select sum(bytes)/(1024*1024) as free_space,tablespace_name
¡¡¡¡from dba_free_space
¡¡¡¡group by tablespace_name;
¡¡¡¡SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE,
¡¡¡¡(B.BYTE ......