MySQL count(*) Óë count(col) ²éѯЧÂʱȽÏ
MySQL count(*) Óë count(col) ²éѯЧÂʱȽÏ
ÓÅ»¯×ܽ᣺
1.ÈκÎÇé¿öÏÂSELECT COUNT(*) from xxx ÊÇ×îÓÅÑ¡Ôñ£»
2.¾¡Á¿¼õÉÙSELECT
COUNT(*) from xxx WHERE COL = ‘xxx’ ÕâÖÖ²éѯ£»
3.¶Å¾øSELECT COUNT(COL) from tablename WHERE COL = ‘xxx’
µÄ³öÏÖ¡£(ÆäÖÐCOL·ÇÖ÷¼ü)
»·¾³£º
MySQL°æ±¾£º5.0.45
OS£ºWindows XP SP3
Êý
¾Ý±íÒ»£ºsphinx
+———-+——————+——+—–+———+—————-+
| Field |
Type | Null | Key | Default | Extra |
+———-+——————+——+—–+———+—————-+
|
id | int(10) unsigned | NO | PRI | NULL | auto_increment |
|
til | varchar(100) | NO | | | |
|
content | text | NO | | | |
|
dataline | int(11) | NO | | | |
+———-+——————+——+—–+———+—————-+
¼Ç
¼Êý£º1120100
²éѯһ£º
mysql>
Ïà¹ØÎĵµ£º
mysqlÃüÁîÐг£ÓÃÃüÁî
µÚÒ»ÕС¢mysql·þÎñµÄÆô¶¯ºÍÍ£Ö¹
net stop mysql
net start mysql
µÚ¶þÕС¢µÇ½mysql
Óï·¨ÈçÏ£º mysql -uÓû§Ãû -pÓû§ÃÜÂë
¼üÈëÃüÁîmysql -uroot -p£¬ »Ø³µºóÌáʾÄãÊäÈëÃÜÂ룬ÊäÈë12345£¬È»ºó»Ø³µ¼´¿É½øÈëµ½mysqlÖÐÁË£¬mysqlµÄÌáʾ·ûÊÇ£º
mysql>
×¢Ò⣬Èç¹ûÊÇÁ¬½Óµ½ÁíÍâµÄ»úÆ÷ÉÏ£¬ÔòÐèÒª¼ ......
£¨1£©ÒÔubuntuµÄrootÓû§µÇ½
£¨2£©Í£Ö¹MYSQL·þÎñÆ÷£º
/etc/init.d/mysql stop
£¨3£©Ìø¹ýÊÚȨ±íÖ´ÐÐMYSQL·þÎñÆ÷£º
mysqld_safe --skip-grant-tables --skip-networking &
(×¢£º²ÎÊý--skip-grant-tablesΪÌø¹ýÊÚȨ±í£»--sk ......
½ñÌì¿´µ½Ò»Æª¹ØÓÚubuntuÏÂÅäÖÃApache+Mysql+PHPµÄÎÄÕ£¬¾õµÃºÜÓÐÓ㬼ÓÒÔ×Ô¼ºµÄÀí½âºÍ±àд£¬¼Ç¼ÏÂÀ´¡£
Ò»¡¢ApacheµÄ°²×°
Apache×÷Ϊһ¸ö¹¦ÄÜÇ¿´óµÄWeb³ÌÐò£¬×ÔÈ»ÊǼܽ¨Web·þÎñÆ÷µÄÊ×Ñ¡£¬ºÃÁË£¬ÏÂÃæÎÒÃǾÍÀ´°²×°Apache¡£ÔÚÖÕ¶ËÏÂÊäÈëÏÂÔÚÃæÃüÁ
sudo apt-get i ......
×î½üÒòΪÍüÁËmysqlµÄrootÃÜÂ룬ÉÏÍøGoogleһϣ¬ÏÖÔڰѲ½Öè¼Çһϣ¬·ÀÖ¹ÒÔºóÍüÁË¡£
ÎÒÓõÄÊÇxamppÈí¼þ°ü¡£
1. ֹͣmysql
2. ´ò¿ªcmd£¬Çл»Ä¿Â¼µ½ \xampp\mysql\bin, ÔËÐÐ
mysqld -skip-grant-tables
ÕâÌõÃüÁîÊÇÌø¹ýȨÏÞ¼ì²éÆô¶¯mysql·þÎñ
3. ´ò¿ªÁíÒ»¸öcmd£¬Í¬ÑùÇл»Ä¿ ......
Mysql ·ÖÇøÏà¹Ø×ÊÔ´
http://www.bigheaddba.net/article/y2009/339_mysql%E5%88%86%E5%8C%BA%E8%A1%A8%E5%B1%80%E9%99%90%E6%80%A7%E6%80%BB%E7%BB%93.html
http://www.ooso.net/archives/217
http://dev.mysql.com/doc/refman/5.1/zh/partitioning.html#partitioning-range
http://hi.baidu.com/zhangguanshi/blog/i ......