PHP: How to foreach in foreach with condition?

Question

I have two MySQL tables, both connected via MySQL JOIN:

TableA:
hom_id  con_id
3       4
5       3

TableB:
hom_id  con_id  hp_id
3       4       1
3       4       2

My pseudo PHP Code:

foreach ($hom as $h) //from TableA
    echo $h->con_id
---myidea---    
        foreach ($pro as $p) //from TableB
            echo $p->hp_id
        endforeach
---END---
endforeach

The HTML result I got is:

Result HTML Table:
con_id      hp_id
3           1 2
4           1 2

What I want to have is:

result HTML:
con_id      hp_id
3           
4           1 2

I am pretty sure, that its just few line of php code which I have to change. But I can't see the answer, please give me a hint how to change it. Thanks

Answer 1

Guess a simple if would solve your problem, if I got ir right.

foreach ($hom as $h) {//from TableA
    echo $h->con_id
    foreach ($pro as $p) { //from TableB
        if ($p->con_id == $h->con_id) {
            echo $p->hp_id
        }
    }
}

Or, maybe you should just handle it in your SQL query, using a LEFT JOIN

Answer 2

You can use following sql statement:

select a.con_id,group_concat(b.hp_id SEPARATOR " ") as hp_id
from tableA a
left join tableB b on(a.hom_id=b.hom_id and a.con_id=b.con_id)
group by a.hom_id,a.con_id

It will give the result as per your requirement.

Answer 3

Why don't you try change your query?

SELECT A.con_id, B.hp_id
FROM A
LEFT JOIN B ON(A.con_id = B.con_id)

And do a simple foreach

foreach($result as $res)
{
    echo $res->con_id, $res->hp_id
}