为什么结果集的计数总是0？

I'm trying to do a distinct count inside my query and return the field, but it continues to return 0.

// Get the total 
$query = "select count (distinct field_name) from table_name";

$rs = $conn->execute($query);

$count = $rs->Fields(0)->value;

echo $count;

Can I not call field on a count value?

http://phplens.com/lens/adodb/docs-adodb.htm#fields

$query = "select count (distinct field_name) as cnt from table_name";
...
$count = $rs->Fields[0];

or 
$count = $rs->Fields("cnt");

You can use mysql_num_rows to get the exact records returned in resultset