Question

I have table contains img_id and likes columns.
Example:

 1  1
 1  1
 1  0
 2  0
 2  0
 3  1

so when run this queries:

select img_id, count(likes)
from my_table
where likes = 1
group by img_id

here’s the result:

1  2
3  1

and whe I run:

select img_id, count(likes)
from my_table
where likes = 0
group by img_id

the result is:

1 1
2 2

my question is:

how can i return in query1 img_id 2 = 0 , I mean img_id = 2 has no likes
also in query 2 img_id = 3 has no dislikes so i need to return 3 -> 0

Answer 1

In MySQL and SQL Server,

SELECT  img_id,
        SUM(CASE WHEN likes = 1 THEN 1 ELSE 0 END) totalLikes,
        SUM(CASE WHEN likes = 0 THEN 1 ELSE 0 END) totalDisLikes
FROM    tableName
GROUP   BY img_ID

or simply in MySQL,

SELECT  img_id,
        SUM(likes = 1) totalLikes,
        SUM(likes = 0) totalDisLikes
FROM    tableName
GROUP   BY img_ID

• SQLFiddle Demo (BOTH)