sql优化
原语句：SELECT id, catid, title, keywords, description, inputtime
FROM news
WHERE catid = 5827117610
ORDER BY id DESC LIMIT 1250, 50
WHERE catid = 5827117610
ORDER BY id DESC LIMIT 1250, 50
优化后：SELECT id, catid, title, keywords, description, inputtime
FROM news
inner join (select id
from news
where catid = 5827117610
ORDER BY id DESC LIMIT 1250, 50) as lim
using (id);
FROM news
inner join (select id
from news
where catid = 5827117610
ORDER BY id DESC LIMIT 1250, 50) as lim
using (id);
