Pure SQL question

Squatrem · #1 (**permalink**) 11-16-04, 17:18

I'm not sure it's the right forum to post this question but as I'm working on mysql, I though you could help me.

I have two tables : A(id_A, name_A) and B(id_B, id_A) and I would like to select each (name_A, id_A) with its number of occurence (0 or more) in table B.
Something like :

Code:

SELECT A.id_A, A.name_A, count(B.id_A)
FROM A, B
WHERE A.id_A = B.id_A
GROUP BY A.id_A, A.name_A

But, of course, this query doesn't show name_As that have 0 occurence in B....

Does anybody have a solution ?

Squatrem · #2 (**permalink**) 11-16-04, 18:14

OK, OK, one more time I reply to myself ..

For others SQL newbies like me that could be interested, the solution is : LEFT JOIN.

The query looks like :

SELECT A.id_A, A.name_A, count(B.id_A)
FROM A
LEFT JOIN B
ON A.id_A = B.id_A
GROUP BY A.id_A, A.name_A

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