select left join table use and condition - sql

Question

these two query output different result,
I have question AND m.status = $1 ...each condition follow the left join table or move to the final part, thats different ??
query 1
SELECT count(mua.*)
AS total_row_count
FROM media_user_action mua
LEFT JOIN media m ON m.id = mua.media_id
AND m.status = $1
LEFT JOIN gallery_media gm ON gm.id = mua.media_id
LEFT JOIN gallery g ON g.id = gm.gallery_id
AND g.status = $1
LEFT JOIN "user" mcbu ON mcbu.id = m.create_by_user_id
AND mcbu.status = $1
LEFT JOIN "user" gcbu ON gcbu.id = g.create_by_user_id
AND gcbu.status = $1
WHERE mua.user_id = $2
query 2
SELECT count(mua.*)
AS total_row_count
FROM media_user_action mua
LEFT JOIN media m ON m.id = mua.media_id
LEFT JOIN gallery_media gm ON gm.id = mua.media_id
LEFT JOIN gallery g ON g.id = gm.gallery_id
LEFT JOIN "user" mcbu ON mcbu.id = m.create_by_user_id
LEFT JOIN "user" gcbu ON gcbu.id = g.create_by_user_id
WHERE
m.status = $1
AND g.status = $1
AND mcbu.status = $1
AND gcbu.status = $1
AND mua.user_id = $2
UPDATE
base on below answer
if I want make sure return result, must all related/left join table status both equal $1, ( join table recode could be null) so I have to add AND x.status .. follow the join table, right?

Answer 1

When you use left outer join, value of the right table may be NULL.
For simplicity's sake, let say we have
Table A (id, name) and Table B (fid, status)
Then query1 will be like
select A.id, B.status
from A
left join (select * from B where status = $1)
on A.id = B.fid;
so result could have B.status is NULL
And query2 will be like
select C.*
from (select A.id, B.status
from A
left join B
on A.id = B.fid
) C
where C.status = $1;
It's equal to
select *
from A
inner join B
on A.id = B.fid
where B.status = $1;
So B.status must exactly be $1, and is never NULL

Answer 2

When you put WHERE conditions on tables that you have LEFT JOIN-ed, and that require some their fields to have non-NULL values, then you are actually converting the LEFT JOIN into an INNER JOIN.
This is because a LEFT JOIN may produce results where the joined table has no matching record. In that case all fields of that "virtual" record have value NULL. So by requiring that one of those fields is not null, you remove those instances from the result.
If on the contrary, you put such conditions in the LEFT JOIN condition, then you do not break this mechanism, where the a non-match will still give a result, albeit with NULL.

Answer 3

An outer join means that additionally to an inner join, when no match is found a mock record with all columns null gets joined.
So let's say for one mua we don't find a matching m. Then we get an m record with all columns null. m.status is null. With WHERE m.status = $1 you dismiss that record, however, so you are where you were with a simple inner join.
Criteria on outer-joined tables belongs in the ON clause.