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

ÔÚMYSQLÖÐvarcharת»»³Édouble½øÐбȽÏÎÊÌâ

ÎÒÓÃhibernateдHQLÓï¾ä£¬Ïë°Ñ±íÖеÄÒ»¸övarchar×ֶεÄÖµ½øÐбȽϣ¬Õâ¸öÖµÊÇÓÐСÊý²¿·ÖµÄ£¬²»ÈçÒ»¸öcommentsShopid×ֶΣ¬´æµÄÊý¾Ýʱ5.0£¬ÀàÐÍÊÇvarchar£¬ÎÒÏë²éѯ³öÀ´µ±Õâ¸öÖµ´óÓÚ4.0µÄʱºò¾ÍÈ¡³öÀ´¡£ÇëÎʸ÷λ´óÏÀÔõôʵÏÖ¡£
ÎÒʹÓÃ"from BbsScomments b where b.commentsShopid="+id+" and cast(b.commentsPingjia as decimal£¨10£¬3£©)>="+4.0
µ«hibernateºÃÏñ¶ÔcastÕâ¸öº¯Êý²»´óÖ§³Ö»òÕß˵¶ÔdecimalÀàÐͲ»´óÖ§³Ö¡£
²»ÖªµÀ¸÷λÓÐʲôºÃµÄ·½·¨Äܹ»ÊµÏÖ

"from BbsScomments b where b.commentsShopid="+id+" and cast(b.commentsPingjia as decimal£¨10£¬3£©)>="+4.0
-->ÊDz»ÊÇÒýºÅÎÊÌâ
"from BbsScomments b where b.commentsShopid="+id+" and cast(b.commentsPingjia as decimal£¨10£¬3£©)>=4.0 "

¶àл2λµÄ£¬Ó¦¸Ã²»ÊÇÒýºÅµÄÎÊÌ⣬createSQLQueryÕâ¸ö·½·¨¿ÉÒÔ£¬ÎÒµ±Ê±Õ¦¾ÍûÏëµ½ÄØ£¡£¡


Ïà¹ØÎÊ´ð£º

mysqlµÄÁ¬½Ó³¬Ê±Ê±¼äÔõôÉèÖà - VC/MFC / Êý¾Ý¿â

ÎÒÊÇÓÃmysql×Ô´øµÄC API
if(mysql_real_connect(&mysql,"125.0.0.108","root","root","home",3306,NULL,0))

AfxMessageBox("Êý¾Ý¿âÁ¬½Óʧ°Ü") ......

eclipseÓëmySQLµÄÎÊÌâ - Java / Eclipse

ÔÚ°²×°Java±àÒëÆ÷µÄEclipseµÄʱºò£¬¶Ô»·¾³±äÁ¿½øÐÐÁËÅäÖã¬ÔÚ°²×°MySQlµÄʱºòÒ²Òª¶Ô»·¾³±äÁ¿½øÐÐÅäÖã»ÄÇôºóÃæµÄÅäÖûáÓ°ÏìÇ°ÃæµÄEclipseµÄÅäÖÃÂð£¿
Çë´ó¼Ò¶àÖ¸½Ì~£¡Ð»Ð»£¡
²»»á°Ñ£¬ÎÒÕâ¶¼×°Á赀 ÎÒϵͳÀï »¹×°ÁË ......

ÓйØmysqlµÄÎÊÌ⣡ - Java / Web ¿ª·¢

ÎÒµÄmysqlÔõôûÓа취дÈëÖÐÎÄÊý¾Ý£¿Ö»ÒªÊÇÊý¾ÝдÈëÊý¾Ý¿âʱ ¾Í»á±ä³ÉÈý¸öÎʺŠ£¿Çë½Ì¸ßÈË£¡£¡
linux? ÔõôдÈëµÄ

ÔÚmysqlÖÐÖ´ÐÐ show variables like 'character%'Ìù½á¹û³öÀ´¡£

ÔÚ°²×°MYSLQʱ½«Êý¾Ý¿âµÄ×Ö· ......

mysqlÖÐÎÄÂÒÂë - ÆäËûÊý¾Ý¿â¿ª·¢ / MySQL/Postgresql

ÔÚC++³ÌÐòÖÐͨ¹ýmysqlµÄC APIÖ±½ÓÁ¬½ÓÊý¾Ý¿â£¬µ±°ÑÖÐÎIJåÈëmysqlµÄʱºò£¬¾Í±ä³ÉÂÒÂëÁË.
»¹ÓоÍÊÇʹÓÃload°ÑÎı¾Îļþµ¼ÈëmysqlÊý¾Ý¿â£¬ÎÞÂÛÎı¾ÎļþÊÇANSI±àÂ뻹ÊÇutf8±àÂ룬µ¼ÈëÖ®ºó¶¼ÊÇÂÒÂë¡£
ÆäÖÐmysqµÄ±àÂë¸ñʽ ......

¹ØÓÚMySQLɾ³ý¼Ç¼ºóIDÈçºÎÁªÏµ

id INT NOT NULL PRIMARY KEY AUTO_INCREMENT
È»ºóɾ³ýÊý¾Ý¿âÖеÄÈô¸ÉÖØ¸´¼Ç¼ºóID±äµÄ²»Á¬Ðø£¬ÈçºÎ±äµÃÁ¬Ðø£¿£¿
ÔËÐÐ
ALTER TABLE tablename DROP id;
ALTER TABLE tablename ADD id INT NOT NULL PRIMARY KEY ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ