比较数组中的条目并删除重复项（PHP，MySQL）

Question

I have this little task I'm trying to accomplish in PHP/MySQL.

We're collecting fax-numbers (and other data) from customers that we'll use in case we have a problem with our operations at the company I work for (not in programming, don't worry).

Basically I have an array that looks something like this.

   Array
   [1]
      [company] => "Company A"
      [fax] => "031-558330"

   [2]
      [company] => "Company B"
      [fax] => "031558330"

   [3]
      [company] => "Company C"
      [fax] => "12345"

Note that [fax] is actually a duplicate in 1 and 2 if you remove the dash (-).

My problem is that I need to remove [2], because it's a duplicate of [1]. Basically, I'm trying to list unique fax numbers and print the company name of that unique fax number.

So far I've done this:

function format_text($text,$number)
{
    $text = str_ireplace(" ","",$text);
    $text = str_ireplace("-","",$text);
    $text = str_ireplace(",","",$text);
    $text = str_ireplace("/","",$text);
    $text = str_ireplace("+46","0",$text);
    $text = trim($text);

    return $text;
}


$fax_result = mysql_query("SELECT fax,company FROM beredskap GROUP BY company") or die(mysql_error());

for($i = 0; $fax_array[$i] = mysql_fetch_assoc($fax_result); $i++) ;
array_pop($fax_array);

for($i = 0; $i<count($fax_array);$i++)
{ 
    $fn = format_text($fax_array[$i]['fax']);
    if(!empty($fn)) {
    echo trim($fax_array[$i]['company']) .",". $fn ."\n";

    }
}

I have no clue as to how I'm supposed to compare two subelements (as the raw data from the SQL might have differences in them, but when stripped of dashes and commas is duplicate to other entries), and then remove the parent key.

I sincerely hoped I've posed this question in the correct fashion.

Anyone willing to help out? Thank you!

Answer 1

You can do it in SQL:

SELECT   company,
         TRIM(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(fax,
           ' ',   '' ),
           '-',   '' ),
           ',',   '' ),
           '/',   '' ),
           '+46', '0')
         ) AS faxno
FROM     beredskap
GROUP BY faxno

Note that where the same fax number appears in the table against different companies, the above query will select one of those companies indeterminately. If in such cases you would prefer to choose a particular company, please clarify how one determines the company that is to be selected.

Note also that this grouping will result in multiple entries in the resultset for a single company if that company has records with different fax numbers in the beredskap table, whereas your original query would have indeterminately chosen only one of such company's fax numbers. If this is not your desired behaviour, please clarify how one determines the fax number that is to be selected.