Question

当用户删除我刚设置的帖子或评论时，delete列为1。

问题是，我使用计数向用户显示他在帖子上有多少评论。

select c.nome, p.foto, c.user, p.user, count(DISTINCT comentarios.id) as comentarios_count from posts p 
join cadastro c on p.user=c.id 
left join comentarios on comentarios.foto = p.id
where p.delete='0' and comentarios.delete='0'
group by p.id
order by p.id desc limit ?

问题是comentarios.delete =＆＃39; 0＆＃39;将仅选择至少有一条评论的帖子。我想选择所有帖子，但只计算delete设置为0的评论。怎么了？

Answer 1

如何选择所有并只删除删除

select c.nome, p.foto, c.user, p.user, count(DISTINCT comentarios.id) -sum(comentarios.delete) as comentarios_count from posts p 
join cadastro c on p.user=c.id 
left join comentarios on comentarios.foto = p.id
where p.delete='0' 
group by p.id
order by p.id desc limit ?

Answer 2

您可以使用条件求和而不是计数，如下所示：

select c.nome, p.foto, c.user, p.user,
SUM(CASE comentarios.Deleted WHEN 0 THEN 1 ELSE 0 END)
as comentarios_count from posts p 
join cadastro c on p.user=c.id 
left join comentarios on comentarios.foto = p.id
where p.delete='0' 
group by p.id
order by p.id desc limit ?

它将计算评论未删除，并且似乎比计算每个帖子的COUNT和SUM更快

删除用户评论但保留 - 计数

2 个答案: