去除数据库里重复的记录,说下原理。先找到表中第一条记录,然后根据这条记录去找与这条记录某个字段相同的,但id不同的记录。删除。效率不是很高,但能用
$start = 0; $k = 10000; while(1){ if($k%10000 == 0){ $con = mysql_connect("localhost","root","root"); //链接数据库 地址:localhost,数据库用户名:getinfo,数据库密码:test123 mysql_select_db("test"); //选择表名 mysql_query("set names utf8"); //执行sql语句 设置字符集为UTF8 } $sql = "select * from site_link_3 where lid>$start order by lid asc limit 0,1"; $result = mysql_query($sql); $num = mysql_num_rows($result); if($num == 0){ die('finish'); //退出, 并打印finish } $info = mysql_fetch_assoc($result); mysql_query("delete from site_link_3 where lid!=".$info['lid']." and link='".$info['link']."'"); //去除重复link $start = $info['lid']; echo $info['lid']."\r\n"; }
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