mysql - Return zero instead NULL in subquery -

i need count posts each author. i'm using subquery count them. author has not post, result null, wish 0.

select id, name,     (select count(id)     posts     post.author = authors.id     group author) post_num authors order post_num desc 

how can solve problem?

use coalesce:

select id, name,        coalesce((select count(id)                   posts                   post.author = authors.id                   group author), 0) post_num authors  order post_num desc