如何合并这两个SQL查询？

Question

架构：http://pastebin.com/jU3HmmNM

$mainfetch = "SELECT * FROM status ORDER BY status_id DESC LIMIT 10,0";

while($mainfetch -> $result) {
  $subquery = SELECT COUNT(*) FROM status s, likes l WHERE s.status_id = l.status_id AND l.member_id = 1;
$liked = $query->row();
if($liked > 0) {
//liked
}else {
//not liked
}
}

所以这不是最优的，因为$ subquery每次都会执行10次，我希望将$子查询添加到$ mainfetch，我怎么能加入它们呢？

Answer 1

你只需要在s.status_id = l.status_id添加一个左连接...然后你也得到l.status_id：如果它是null，那么成员1不喜欢它，否则当然是。< / p>

Answer 2

使用您提供的架构：

SELECT s.status_id, s.text_id, count(l.status_id) as like_count
FROM status AS s LEFT JOIN likes AS l ON (s.status_id = l.status_id AND l.member_id = 1) 
group by s.status_id, s.text_id
ORDER BY status_id DESC
LIMIT 10,0