请教一下 第二个sql 为啥 会查出null 数据, 或者出现两条数据 我把sql 贴出来
SELECT a.id,a.pid
FROM `shopinfo` a
WHERE a.id=(select id
from ( SELECT id,rand() as random_num
FROM bookinfo
where status='1') a
order by a.random_num
limit 1)
SELECT a.id,a.pid
FROM `shopinfo` a
WHERE a.id=( SELECT id
FROM bookinfo
where status='1'
order by rand()
LIMIT 1 )