Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

Ö´ÐÐSQLÈ¡PostgreSQLÊý¾Ý¿â»ò±í´óС

ÔÚPostgreSQL8.1.3ÉÏ¿ÉÒÔwork
1. È¡Êý¾Ý¿â´óС
SELECT pg_size_pretty(pg_database_size('somedatabase')) As fulldbsize
2. È¡±í´óС
SELECT pg_size_pretty(pg_total_relation_size('someschema.sometable')) As fulltblsize, pg_size_pretty(pg_relation_size('someschema.sometable')) As justthetblsize
Ô­Ìù£º
http://www.postgresonline.com/journal/index.php?/archives/110-Determining-size-of-database,-schema,-tables,-and-geometry.html


Ïà¹ØÎĵµ£º

Oracle SQLÓï¾ä

ORDER BY ÅÅÐò
 
ASC ÉýÐò(ĬÈÏ)
 DESC ½µÐò
 
select * from s_emp order by dept_id , salary desc
²¿ÃźÅÉýÐò£¬¹¤×ʽµÐò
¹Ø¼ü×ÖdistinctÒ²»á´¥·¢ÅÅÐò²Ù×÷¡£
 
select * from employee order by 1; //°´µÚÒ»×Ö¶ÎÅÅÐò
NULL±»ÈÏΪÎÞÇî´ó¡£order by ¿ÉÒÔ¸ú±ðÃû¡£
 
select table_name ......

pl/sqlÀûÓÃrownumÈ¡µÃÅÅÐòºóµÄ²¿·ÖÐÐÐòÁÐ

ÎÒÃÇʹÓÃoracleµÄÈ˶¼ÖªµÀ¿ÉÒÔͨ¹ýrownumαÁеõ½²éѯ½á¹ûÐòÁÐÇ°ÃæµÄÖ¸¶¨µÄÐУ¬ÎªÁËÏÂÃæ¸üºÃµÄ½øÐÐ˵Ã÷ÎÊÌ⣬ÎÒÃÇÏÈÀ´´´½¨Ò»¸öÊý¾Ý±ítable1£º
create table table1
(AAA integer primary key,
BBB varchar(30));
È»ºóÔÚtable1ÖвåÈë9ÌõÊý¾Ý£º
insert into table1 values (8, 'good');
insert into table1 values (7 ......

10. ¾«ÃîSQL語¾ä

         1. ˵Ã÷£º¸´ÖƱí(Ö»¸´Öƽṹ£¬Ô´±íÃû£ºa£¬Ð±íÃû£ºb)
SQL: select * into b from a where 1<>1;
        2. ˵Ã÷£º¿½±´±í(¿½±´Êý¾Ý£¬Ô´±íÃû£ºa£¬Ä¿±ê±íÃû£ºb)
SQL: insert into b(a, b, c) select d, e, f from b;
&nb ......

SQL Server 2008 Spatial, PostgreSQL/PostGIS 1.3

General Overview
FeatureSQL Server 2008 (RC0)MySQL 5.1/6PostgreSQL 8.3/PostGIS 1.3/1.4
OS
Windows XP, Windows Vista, Windows 2003, Windows 2008
Windows XP, Windows Vista, (haven't tested on 2008), Linux, Unix, Mac
Windows 2000+ (including Vista and 2003, haven't tested on 2008), Linux, Unix, Ma ......

sql È¡·´

 update anketo1 set fb = substring('10',fb+1,1) WHERE id =5
ºóÀ´ÎÊÁËBM,BM˵ֱ½ÓÈ¡·´
update anketo1 set fb = ~ fb WHERE id =5
ÎÒ¸æËßÁËBMÓÃsubstringÒ²¿ÉÒÔ.
BM˵:"Õâ¼Ò»ïÀ÷º¦£¬ÕâÒ²ÄÜÏë³ö,ÕâÊôÓÚаÃÅÎ书."
×îºóÓÖÏëµ½ÓÃABSÈ¡¾ø¶ÔÖµÒ²¿ÉÒÔ
update anketo1 set fb = abs(fb-1)
ÎÒ¾õµÃ²»¹ÜÊÇʲôÎ书,ÄÜÖ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ