MysqlÓÅ»¯·½°¸Ö®Ë÷ÒýµÄʹÓÃ
Ë÷ÒýÓÃÓÚ¿ìËÙÕÒ³öÔÚij¸öÁÐÖÐÓÐÒ»Ìض¨ÖµµÄÐС£²»Ê¹ÓÃË÷Òý£¬MySQL±ØÐë´ÓµÚ1Ìõ¼Ç¼¿ªÊ¼È»ºó¶ÁÍêÕû¸ö±íÖ±µ½ÕÒ³öÏà¹ØµÄÐС£±íÔ½´ó£¬»¨·ÑµÄʱ¼äÔ½¶à¡£Èç¹û±íÖвéѯµÄÁÐÓÐÒ»¸öË÷Òý£¬MySQLÄÜ¿ìËÙµ½´ïÒ»¸öλÖÃÈ¥ËÑÑ°µ½Êý¾ÝÎļþµÄÖм䣬ûÓбØÒª¿´ËùÓÐÊý¾Ý¡£Èç¹ûÒ»¸ö±íÓÐ1000ÐУ¬Õâ±È˳Ðò¶ÁÈ¡ÖÁÉÙ¿ì100±¶¡£×¢ÒâÈç¹ûÄãÐèÒª·ÃÎʴ󲿷ÖÐУ¬Ë³Ðò¶ÁÈ¡Òª¿ìµÃ¶à£¬ÒòΪ´ËʱÎÒÃDZÜÃâ´ÅÅÌËÑË÷¡£
´ó¶àÊýMySQLË÷Òý(PRIMARY KEY¡¢UNIQUE¡¢INDEXºÍFULLTEXT)ÔÚBÊ÷Öд洢¡£Ö»ÊÇ¿Õ¼äÁÐÀàÐ͵ÄË÷ÒýʹÓÃR-Ê÷£¬²¢ÇÒMEMORY±í»¹Ö§³ÖhashË÷Òý¡£
×Ö·û´®×Ô¶¯µØѹËõǰ׺ºÍ½áβ¿Õ¸ñ¡£
×ܵÄÀ´Ëµ£¬°´ºóÃæµÄÌÖÂÛʹÓÃË÷Òý¡£±¾½Ú×îºóÃèÊöhashË÷Òý(ÓÃÓÚMEMORY±í)µÄÌØÕ÷¡£
Ë÷ÒýÓÃÓÚÏÂÃæµÄ²Ù×÷£º
· ¿ìËÙÕÒ³öÆ¥ÅäÒ»¸öWHERE×Ó¾äµÄÐС£
· ɾ³ýÐС£Èç¹û¿ÉÒÔÔÚ¶à¸öË÷ÒýÖнøÐÐÑ¡Ôñ£¬MySQLͨ³£Ê¹ÓÃÕÒµ½×îÉÙÐеÄË÷Òý¡£
· µ±Ö´ÐÐÁª½Óʱ£¬´ÓÆäËü±í¼ìË÷ÐС£
· ¶Ô¾ßÌåÓÐË÷ÒýµÄÁÐkey_colÕÒ³öMAX()»òMIN()Öµ¡£ÓÉÔ¤´¦ÀíÆ÷½øÐÐÓÅ»¯£¬¼ì²éÊÇ·ñ¶ÔË÷ÒýÖÐÔÚkey_col֮ǰ·¢ÉúËùÓйؼü×ÖÔªËØʹÓÃÁËWHERE key_part_# = constant¡£ÔÚÕâÖÖÇé¿öÏ£¬MySQLΪÿ¸öMIN()»òMAX()±í´ïʽִÐÐÒ»´Î¹Ø¼ü×Ö²éÕÒ£¬²¢Óó£ÊýÌæ»»Ëü¡£Èç¹ûËùÓбí´ïʽÌ滻Ϊ³£Á¿£¬²éѯÁ¢¼´·µ»Ø¡£ÀýÈ磺
· SELECT MIN(key_part2),MAX(key_part2)
· from tbl_name WHERE key_part1=10;
· Èç¹û¶ÔÒ»¸ö¿ÉÓùؼü×ÖµÄ×î×óÃæµÄǰ׺½øÐÐÁËÅÅÐò»ò·Ö×é(ÀýÈ磬ORDER BY key_part_1,key_part_2)£¬ÅÅÐò»ò·Ö×éÒ»¸ö±í¡£Èç¹ûËùÓйؼü×ÖÔªËغóÃæÓÐDESC£¬¹Ø¼ü×ÖÒÔµ¹Ðò±»¶ÁÈ¡¡£
· ÔÚһЩÇé¿öÖУ¬¿ÉÒÔ¶ÔÒ»¸ö²éѯ½øÐÐÓÅ»¯ÒԱ㲻ÓòéѯÊý¾ÝÐм´¿ÉÒÔ¼ìË÷Öµ¡£Èç¹û²éѯֻʹÓÃÀ´×Ôij¸ö±íµÄÊý×ÖÐͲ¢ÇÒ¹¹³ÉÄ
Ïà¹ØÎĵµ£º
²éѯÊÇÊý¾Ý¿â¼¼ÊõÖÐ×î³£ÓõIJÙ×÷¡£²éѯ²Ù×÷µÄ¹ý³Ì±È½Ï¼òµ¥£¬Ê×ÏÈ´Ó¿Í»§¶Ë·¢³ö²éѯµÄSQLÓï¾ä£¬Êý¾Ý¿â·þÎñ¶ËÔÚ½ÓÊÕµ½ÓÉ¿Í»§¶Ë·¢À´µÄSQLÓï¾äºó£¬Ö´ÐÐÕâÌõSQLÓï¾ä£¬È»ºó½«²éѯµ½µÄ½á¹û·µ»Ø¸ø¿Í»§¶Ë¡£ËäÈ»¹ý³ÌºÜ¼òµ¥£¬µ«²»Í¬µÄ²éѯ·½Ê½ºÍÊý¾Ý¿âÉèÖ㬶ԲéѯµÄÐÔÄܽ«»áÓкÜÔÚµÄÓ°Ïì¡£
Òò´Ë£¬±¾ÎľÍÔÚMySQLÖг£ÓõIJéѯÓÅ»¯¼¼Êõ½ø ......
<!--#include file="zheboconn.asp"-->
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB2312" />
<title>aspºÍmysql·ÖÒ³´úÂë</title>
<style type="text/css">
<!--
.STYLE3 {
fon ......
1¡¢ÏÔʾÊý¾Ý¿âÁÐ±í¡£
show databases;
¸Õ¿ªÊ¼Ê±²ÅÁ½¸öÊý¾Ý¿â£ºmysqlºÍtest¡£mysql¿âºÜÖØÒªËüÀïÃæÓÐMYSQLµÄϵͳÐÅÏ¢£¬ÎÒÃǸÄÃÜÂëºÍÐÂÔöÓû§£¬Êµ¼ÊÉϾÍÊÇÓÃÕâ¸ö¿â½øÐкÃ×÷¡£
2¡¢ÏÔʾ¿âÖеÄÊý¾Ý±í£º
use mysql£» £¯£¯´ò¿ª¿â£¬Ñ§¹ýFOXBASEµÄÒ»¶¨²»»áÄ°Éú°É
show tables;
3¡¢ÏÔʾÊý¾Ý±íµÄ½á¹¹£º
describe ±í ......
MysqlËùÖ§³ÖµÄÒýÇæÄ¿Ç°ÓÐÒÔϼ¸ÖÖ£º
MyISAM,InnoDB,MERGE,MEMORY(HEAR),BDB(BerkeleyDB),EXAMPLE,FEDERATED,ARCHIVE,CSV,BLACKHOLE.
ΪʲôҪÓÐÕâô¶àÒýÇ棿Ö÷ÒªÊÇMysqlÊÇÒ»¿î¼«ÎªÇ¿´óµÄÊý¾Ý¿â£¬ËüÊÊÓ¦ºÜ¶à²»Í¬µÄÔËÐл·¾³£¬ÎªÁËÂú×ã¸÷ÖÖ²»Í¬µÄÔËÐл·¾³Óë´æ´¢·½°¸µÄÐèÒª£¬ÕâЩËÑË÷ÒýÇæÒ²¾ÍÓ¦Ô˶øÉú£¨²»¹âÊÇΪÁËÅäºÏMysql ......
mysqlÎļþµ¼ÈëÂÒÂëÎÊÌâµÄ½â¾ö£º
1 ÃüÁî²ì¿´×Ö·ûÉèÖá£
mysql> show variables like "%char%";
2 ½«²»ÊÇutf-8µÄ¶¼¸Ä³Éutf8¡£Ö»ÓÐfilesystem²»±ä;
| Variable_name | Value
&nb ......