implode()

I am having difficulty with the implode function. What I am doing is building a string for an UPDATE SQL command. At the end of the building portion of the code, I want to insert a comma between the various fields that will be updated. However, it is not working. Here is a portion of my code...thanks, in advance for any assistance received.... $sqlUpdate = "SET "; if($image11_name != '') $sqlUpdate .= "image11='$image11_name'"; if($image12_name != '') $sqlUpdate .= "image12='$image12_name'"; if($textfield11 != '') $sqlUpdate .= "textfield11='$textfield11'"; if($textfield12 != '') $sqlUpdate .= "textfield12='$textfield12'"; if($textlink11 != '') $sqlUpdate .= "textlink11='$textlink11'"; if($textlink12 != '') $sqlUpdate .= "textlink12='$textlink12'"; $update = implode(",", $sqlUpdate); $sql = "UPDATE mp " .$sqlUpdate; I get a bad parameter message on the line with the call to the Implode function. Questions? Comments? Suggestions? Jef