select fp.fid, fp.message, fp.subject FROM sh_forum_post fp left join sh_forum_threadclass ft on ft.fid=fp.fid where ft.name='列表页图片'
SELECT a.fid,a.message,a.`subject` FROM sh_forum_post a inner join sh_forum_threadclass b on a.fid =b.fid WHERE b.`name` = '列表页图片' 在两表的FID上建立索引
join 查询的效率要比in 高
SELECT sh_forum_post.fid, sh_forum_post.message, sh_forum_post.`subject` FROM sh_forum_post,sh_forum_threadclass WHERE sh_forum_threadclass.fid=sh_forum_post.fid and sh_forum_threadclass.`name` = '列表页图片'
fp.fid,
fp.message,
fp.subject
FROM
sh_forum_post fp
left join sh_forum_threadclass ft on ft.fid=fp.fid
where ft.name='列表页图片'
a.fid,a.message,a.`subject`
FROM
sh_forum_post a inner join sh_forum_threadclass b
on a.fid =b.fid WHERE b.`name` = '列表页图片'
在两表的FID上建立索引
sh_forum_post.fid,
sh_forum_post.message,
sh_forum_post.`subject`
FROM
sh_forum_post,sh_forum_threadclass
WHERE sh_forum_threadclass.fid=sh_forum_post.fid and
sh_forum_threadclass.`name` = '列表页图片'