Question

I have 2 tables, table A and table B.

Table A has these fields:

id(primary key), 
references_id

Table B also has fields:

id(primary_key) 
references_id. 

Now I am given the ids of A, I need to retrieve A.id and the count(B.references_id) by A.references_id.

How can I do that in a SQL query?

Answer 1

Use LEFT JOIN so it will still show even if the references_id is not present on table B. Try something like this,

SELECT  a.ID, COUNT(b.References_ID) totalCount
FROM    A LEFT JOIN B
            ON a.References_ID = b.References_ID
GROUP BY a.ID