我有一个mysql表,如下所示:当访问者访问网站时,它将访问者id和页面id存储为一行。SELECT COUNT(visid),visid FROM vislog GROUP BY visid ORDER BY COUNT(visid) DESC
但我不知道下一步该怎么计算可以像MySQL查询一样做吗?
PRIMARY KEY (`id`), KEY `name_all` (`name`)name_first_letter MySQL我已经做了一些快速测试,即使在使用索引提示时,我也不确定MySQL是否会选择name_first_letter索引:EXPLAIN SELECT nameSELECT name FROM mytable USE INDEX (name_first_letter)
WHERE SUBSTRING(n