摘要：a数据库多表查询 select a.id,a.title,a.typeid,b.body,a.pubdate,a.keywords,a.description from ras_archives a left join ras_addonarticle b on a.id=b.aid where a 阅读全文

摘要：select a.askid,a.title,GROUP_CONCAT(b.message SEPARATOR '----') as content from gg_ask as a join gg_ask_posts as bon a.askid=b.askid GROUP BY a.askid; 阅读全文

摘要：set long_query_time=1; #设置慢查询时间为1 秒;set global slow_query_log=on; #开启慢查询日志;show global status like 'slow_queries'; #显示慢查询次数show variables like 'long_query_time' ; #显示慢查询时间;show variables like 'slow_query_log' ; #显示慢查询日志是否开启日志文件默认在data目录下在web开发中，我们经常会写出一些SQL语句，一条糟糕的SQL语句可能让你的整 阅读全文