如何访问具有相同名称的多个mysql行的不同表

Question

I think im close to the solution, but not quite getting it.

What im trying to do is get a product.naam and a categorie.naam from 2 different tables. This code below gets me the naam from both and i can acces them both, but now i want everything from product, not just the name and then i don't know how to access it from the $row...

Every little bit of help is appreciated

$kerst_sql = "  SELECT      product.naam, product.prijs AS p_naam, categorie.naam AS c_naam
                FROM        categorie_product, 
                            product, categorie 
                WHERE       product.product_id = categorie_product.product_product_id 
                AND         categorie_product.categorie_categorie_id = '1'
                GROUP BY    product.naam";
$result = mysqli_query($con, $kerst_sql);
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
    echo $row['p_naam'];
    echo $row['c_naam'];
}

Answer 1

If you don't want to explicitly list them all out, you can use SELECT product.*, categorie.naam AS c_naam FROM ... and then access it like this:

echo $row['naam']; // product.naam
echo $row['prijs']; // product.prijs
echo $row['c_naam']; // categorie.naam

But I think it's usually a good idea to select the specific columns you need (and alias them appropriately) instead of using SELECT * . IMO, you should have a real reason to want to use the asterisk, and not just that you don't feel like typing out all the column names.

---

An example of a situation where I would use SELECT * is when I know that I need all the columns that currently exist in the table AND any columns that might be added in the future. For instance, if I were writing an application whose purpose is to display the entire contents of a table.

And when looping through the columns, you want to take care to keep in mind that at any time, columns can be added or removed. So if you're showing them in an HTML table, for instance, make sure you don't hard-code your column headers, because if a column is added or removed from the table, you'll have an extra or missing column.

If this isn't something that you're trying to do, it might be better to just explicitly list out every column that you want to select.