Querying MySQL tables - php

Question

I am working on someone else program. I have 2 tables Products and Seller. These tables are connected and the connection is made in the Seller table. I want to display the Product name from the Products table and also display the Seller who has made the product entry.
This is how I display the product table:
public function getProductName($product_id,$language_id) {
$query = $this->db->query("SELECT name FROM " . DB_PREFIX . "product_description WHERE
product_id = '".(int)$product_id."'
AND language_id = '".(int)$language_id."'");
if($query->row AND $query->row['name'] != '') {
return $query->row['name'];
} else {
return '-';
}
}
The Seller table has fields seller_name, seller_id, sproduct_id. How can I pull the associated seller name for each product?

Answer 1

Using your code:
public function getProductName($product_id, $language_id)
{
$strSQL = "SELECT p.name, s.seller_name FROM " . DB_PREFIX .
"product_description p INNER JOIN " . DB_PREFIX .
"Seller s ON p.product_id = s.sproduct_id WHERE product_id = '" .
intval($product_id) . "' AND language_id = '" .
intval($language_id) . "'";
$query = $this->db->query($strSQL);
if($query->row AND $query->row['name'] != '') {
return $query->row['name'];
} else {
return '-';
}
}
If product_id and language_id are integer values you don't need to enclosed them in ''. Also remember to add error checking to make sure that $product_id and $language_id have valid values for your query. More info on SQL joins.

Answer 2

You'll want to join the two tables together on the common product_id key. Here's the resultant Sql you'll want. Also, if product_id and language_id are integers in the database (as they seem to be in PHP) that you can drop the '':
"SELECT pd.name, s.seller_name
FROM " . DB_PREFIX . ".product_description pd
INNER JOIN " . DB_PREFIX . ".Seller s on pd.product_id = s.sproduct_id
WHERE
product_id = ".(int)$product_id."
AND language_id = ".(int)$language_id.";";