Mysql add temporary column if data not found

Question

I have these two tables in mysql database, Can a query be made like this that if there is no data find for the column islike in like_tbl auto make a temp column with value false.

Like there is no data for post_id = 3 in like_tbl so the result should be like this as I mentioned below.

post_tbl

post_id	uid	fname
1	1	abc
2	1	abc
3	1	abc

like_tbl

likeid	uid	postid	islike
1	2	1	true
2	3	2	true

This is the result I'm looking for:

post_id	uid	fname	islike
1	2	abc	false
2	2	abc	true
3	2	abc	false

Summary I am trying to make a query which will return all post_id and check in like_tbl that the specific user has liked the post or not. If the data is there for the specific post_id of uid in the like_tbl it will return islike column value true otherwise it will return false if no data is found there for that post_id of the specific uid.

I have try this but not helping,

select n.* , e.isLike 
from post_tbl n 
join like_tbl on e.post_id = n.post_id 
where n.uid = '2' 
order by post_id desc

New to mysql DB any help would be appreciated

Answer 1

you could try using ifnull and left join

select n.* , ifnull(e.isLike , 'false')
from post_tbl n 
LEFT JOIN like_tbl e on e.postid = n.post_id 
    AND e.uid = n.uid

order by post_id DESC