SELECT
tpn.news_id,
tpn.title,
tpn.news_group_id,
tpn.send_date
FROM
t_pm_news tpn
WHERE
3 > (
SELECT
COUNT(*)
FROM
t_pm_news t
WHERE
tpn.news_group_id = t.news_group_id AND tpn.send_date <= t.send_date
)
注：时间相同可能会有误差
SELECT
tpn.news_id,
tpn.title,
tpn.news_group_id,
tpn.send_date
FROM
t_pm_news tpn
WHERE
3 > (
SELECT
COUNT(*)
FROM
t_pm_news t
WHERE
tpn.news_group_id = t.news_group_id AND tpn.send_date <= t.send_date
)
注：时间相同可能会有误差