相关疑难解决方法(0)

我需要修改以下MySQL语句以包含来自第三个表的信息......但我很糟糕.

select
    ss.*,
    se.name as engine,
    ss.last_run_at + interval ss.refresh_frequency day as next_run_at,
    se.logo_name    
from 
    searches ss join search_engines se on ss.engine_id = se.id
where
    ss.user_id='.$user_id.'
group by ss.id
order by ss.project_id, ss.domain, ss.keywords

我还需要包括检索projects.project_name通过匹配searches.project_id来projects.id.

我只想将变量"$ read"定义为数据库中的值.我怎样才能做到这一点？

$read =  "SELECT `read` FROM `users` WHERE `id` = '$id'";