Question

I wanted to know if data is present then there must be mysql update query else insert data into mysql table.

What I have done is, I am fetching data from .csv file into mysql using fgetcsv() function.
Then reading each row from csv & putting those four values in four variables & then firing update query.
SO how can I check that if one of the data is not present still update query is working(0 rows successfully updated) so I want to identify that data & insert that into table else if data present my update query will work.

I want to either update or insert data into product_entity_price table.
My script-:

    if(($handle = fopen("/data/sample/items_0420.csv", "r")) !== FALSE) 
    {          
         while (($data = fgetcsv($handle, 8000, ",")) !== FALSE)      
         {
        $num = count($data);
        for ($c=0; $c < $num; $c++) 
        {             
            $temp = $data;             
            $string = implode(";", $temp);           
        }
            $pieces = explode(";", $string);               
            $col1 = $pieces[0];
            $col2 = $pieces[1];         
            $col3 = $pieces[2];               
            $col4 = $pieces[3]; 

    $query_insert = "INSERT INTO import_prices (customer_id, sku, price, website) ".             
    "VALUES($col1,'$col2',$col3,'$col4') ".             
    "ON DUPLICATE KEY UPDATE customer_id=$col1, price=$col3,website='$col4' "; 
        $result = mysql_query($query_insert);

             $query_update = "UPDATE  product_entity_price pep 
             JOIN   catalog_product cp   ON    cp.entity_id = pep.entity_id    
             AND    cp.sku LIKE '$col2'   AND   website_id = $col4 
             JOIN   customer_group cg   ON    cg.customer_group_id = pep.customer_group_id   AND   cg.customer_group_code =  $col1 
SET cpetp.value = ".$col3.";";
             mysql_query($query_update);
          }
    }

Answer 1

Check mysql command replace :

http://dev.mysql.com/doc/refman/5.0/en/replace.html