How to filter record with specific condition?

I have a table called post which contains WordPress posts that have this structure:

ID  post_title  post_type
1   foo1        zoacres-property
2   foo2        zoacres-property
3   foo3        zoacres-property
4   foo4        post

each zoacres-property post have a meta stored inside the meta table:

meta_id post_id meta_key    meta_value
100     1       price       5000
101     2       price       10000
102     3       price       0

I’m trying to filter the zoacres-property post by price, and I successfully did this using this query:

SELECT * 
FROM post p
LEFT JOIN meta m ON p.ID = m.post_id AND m.meta_key = 'price'
AND p.post_type = 'zoacres-property'
GROUP BY p.ID
ORDER BY m.meta_value+0
LIMIT 0,6

which returns:

ID  post_title  post_type           meta_id post_id meta_key    meta_value
3   foo3        zoacres-property    102     3       price       0
1   foo1        zoacres-property    100     1       price       5000
2   foo2        zoacres-property    101     2       price       10000

this result is correct but, I would like to display all the property which have a price of 0 as first (as in the output), and after these, I need to display the property with a non 0 price using DESC, so the correct ouput the I want is:

ID  post_title  post_type           meta_id post_id meta_key    meta_value
3   foo3        zoacres-property    102     3       price       0
2   foo2        zoacres-property    101     2       price       10000
1   foo1        zoacres-property    100     1       price       5000

As you can see the post with price 0 are the firsts displayed, and then I want get all the posts with the high price to lowest. Is possible achieve this?

I also created a FIDDLE HERE.

Answer

You can use conditional ordering as

SELECT * 
FROM post p
JOIN meta m ON p.ID = m.post_id AND m.meta_key = 'price'
AND p.post_type = 'zoacres-property'
ORDER BY m.meta_value+0 = 0 desc, m.meta_value+0 desc
LIMIT 0,6

DEMO