mysql replacing columns in a table

Question

I'm inserting data from a file that has 18 columns, the table that I would like to insert it into has 20 columns. 2 of those columns already contain data. How do I go about inserting the file into the table without overwriting the existing data.

below is a example of the code. note $line .= ',,' is appending two columns because the update wont' work unless the columns match the exact table size of 20 columns. But the $line .= ',,' overwrites the data already inserted. What do i do?

$fcontents = file('data.txt'); 

if(mysql_error())
    echo mysql_error();

for($i=0; $i<sizeof($fcontents); $i++) 
{   
    //strip out double quotes
    $line = ereg_replace('"','',trim($fcontents[$i])); 

    $line .= ',,';

    //strip replace semi-colon with blank spaces
    $line = ereg_replace(';',' ',$line); 

    //single quote in parts records breaks replace code, removing single quote...
    $line = ereg_replace("'",'',$line); 


    //breaks apart the tab delimited row into a array
    $arr = explode(",", $line); 

    //add comma deliminted data back
    mysql_query("REPLACE INTO products VALUES ('". implode("','", $arr) ."')");


}

Answer 1

Specify the column names:

REPLACE INTO products (col1, col2, ...) VALUES (val1, val2, ...)

See the MySQL online manual.