select count(*) as Num FROM `phpbb_posts` where `post_visibility` = 1
gives now the same result.From the post_id I see Member X has deleted the post posted by Member Y on Jun 23, 2019 at 1:08 a.m.
The post text is still in the phpbb_posts table but I don't see it on the bord.
However, I am certain that, as Admin, I was able to consult the text of deleted messages : why can't I anymore ?