Question

Hy, i have a big question … it may sound simple but actually it’s very complicated

I have two mysql tables :

info_cat (id, name)
info_subcat (id, id_info_cat, name)

I want to show the user the info_cat.name followed by info_subcat.name but the problem is that info_cat.name i want to appear just one time.
Something like this:

Laptop

• Hp
• Sony
• Acer

HDD

• Western DIgital
• Seagate
• ETC

So normaly i will query like this (old fashioned)

$query = mysql_query("SELECT * FROM info_cat");
while ($row = mysql_fetch_assoc($query)) {
$id_info_cat = $row['id'];
echo $row['name']; 
 $query2 = mysql_query("SELECT * FROM info_subcat WHERE id_info_cat = '$id_info_cat'");
 while($row2 = mysql_fetch_assoc($query2)) {
 echo $row2['nume'];
 }
}

and i have while within while.
My question is how can i use only a query to acomplish this (i think with JOIN) ??
I have tried the following command :

SELECT info_cat.name, info_subcat.name AS name2, info_subcat.id FROM info_cat, info_subcat WHERE info_cat.id = info_subcat.id_info_cat;

but can’t figure it out how to manipulate data because it will output :

name       name2                 id
Laptop     Acer                  1
Laptop     HP                    2
Laptop     Sony                  3
HDD        Western Digital       4
HDD        Seagate               5
HDD        ETC                   6

and i just want to echo Laptop one time and HDD one time followed by its subcat names.
How can i do that ?

Pleaseee ….

Thank you

Answer 1

Try using GROUP BY and GROUP_CONCAT.

SELECT
    info_cat.name,
    GROUP_CONCAT(info_subcat.name ORDER BY info_subcat.name SEPARATOR ', ')
FROM
    info_cat
        LEFT JOIN
    info_subcat ON (info_car.id = info_subcat.id_info_cat)
GROUP BY
    info_cat.id