使用php访问Prestashop数据库

Question

I am developing a php program. I can not make this code work:

$ref="demo_3";
$ident=comprobarExisteProd($ref);

function comprobarExisteProd ($refer)
{
    $id_product=0;
    $sqlpr = 'SELECT * FROM `'._DB_PREFIX_.'product` WHERE `reference`=(string)$refer';
    $res = Db::getInstance()->executeS($sqlpr);
    var_dump($res);
    echo "<br>";
    if (!$res){
        echo "The product does not exist in database";
        echo "<br>";
    } else{
        $id_product=$res[0]['id_product'];
        $precio=$res[0]['price'];
        echo "The product exist with identifier: : ";
        echo $id_product;
        echo "<br>";
        echo "The product price is: ";
        echo $precio;
        echo "<br>";
    }
    return id_product;
}

However, if I change:

$sqlpr = 'SELECT * FROM `'._DB_PREFIX_.'product` WHERE `reference`=(string)$refer';

with this other:

$sqlpr = 'SELECT * FROM `'._DB_PREFIX_.'product` WHERE `reference`="demo_3"';

Then the code works correctly.

How can I use the function comprobarExisteProd($refer) using the parameter $refer?

I have changed the code many times, but it does not work.

Answer 1

You can't cast the variable $refer inside the statement. The statement should be:

$sqlpr = 'SELECT * FROM `'._DB_PREFIX_.'product` WHERE `reference`="'.(string)$refer.'"';