你试的时候把having子句放在哪里了？having子句必须在groupby之后和order by之前。所以是这样的：

select distinct t1.id, count(t1.ID) as Products from wp_posts t1
inner join wp_woocommerce_order_items t2 on t1.ID = t2.order_id
inner join wp_woocommerce_order_itemmeta t3 on t2.order_item_id = t3.order_item_id
where t3.meta_key = '_product_id' and (t3.meta_value=19549 or t3.meta_value=19547)
and t1.post_status='wc-on-hold'
group by t1.id
having count(t1.id) = 2
order by count(t1.ID) asc

听起来像是一场灾难 having 条款就是你想要的。我将你的问题表述为：

select p.id, count(*) as no_products 
from wp_posts p
inner join wp_woocommerce_order_items oi 
    on p.ID = oi.order_id
inner join wp_woocommerce_order_itemmeta oim 
    on oi.order_item_id = oim.order_item_id
where 
    oim.meta_key = '_product_id' 
    and oim.meta_value in (19549, 19547)
    and p.post_status = 'wc-on-hold'
group by p.id
having count(*) = 2
order by p.id

笔记：
这个 having 子句位于 group by 条款
有意义的表别名使查询更容易理解 in 可以方便地根据值列表检查同一列 count(*) 效率比 count(<column>) （在这里，它在功能上是等效的）
按计数排序是没有用的，因为您已经对它进行了筛选（所有行都有相同的计数）