mysql_num_rows返回错误的值

Question

echo $sql2 = "select uid,username from userstable where username IN(".$usernameStr.")";
$res2 = mysql_query($sql2);
echo "------".mysql_num_rows($res2)."-----"; 

mysql_num_rows returns only 1 record which is the last entry but when I run the query in MySQL it is returning correct number of records.

Where is the problem?

Answer 1

while($rs=mysql_num_rows($res2)){ 
 echo $rs[0].' '.$rs[1];
}