如何找出一个值是否匹配一个可能为空的列？

Question

I am trying to write a function to determine whether or not a given value, $useremail, matches the values in a column member_email1 in a row that matches a given value $gid. Many of the rows have empty / null values in the column member_email1, while others are filled out with emails.

I'd like the function to return zero unless member_email1 actually contains a value that matches $useremail. However right now it seems to be returning 1 in all circumstances. Here is what I have so far:

function IsInvitedToGroup($useremail, $gid){
    global $db;
    $q= "select count(*) from ! where group_id=? AND member_email1=?";
    $res= $db->getOne($q, array('member_email1', $email, $gid));
    if($res > 0) {
        return 1;
    }
    return 0;
}

How can I correct this so that it returns zero whenever $useremail does not match the value in the member_email1 column of the row corresponding to $gid?

Answer 1

As stated, we don't see your db class, but does it work when you use the correct variable $useremail and the params are in the correct order?

$res= $db->getOne($q, array('member_email1', $gid, $useremail));

This was all from my crystal ball.