求一个简单的流程控制语句：如何判断ＭＹＳＱＬ数据库不为空，立即结贴

Question

while($rs=mysql_fetch_object($open)){
$ifhave=1;
echo "<option w_id=".$rs->w_id.">".$rs->w_name."</option>";
}
if(!ifhave) echo"数据库为空";

Answer 1

$connect=mysql_connect("localhost","root","");
mysql_select_db("work");
$sql="select count(*) from work";
$open=mysql_query($sql);
$num=mysql_num_rows($open);if($num<=0){
echo"数据库为空"
}
else
{
while($rs=mysql_fetch_object($open))
{
echo "<option w_id=".$rs->w_id.">".$rs->w_name."</option>";
}}

Answer 2

$connect=mysql_connect("localhost","root","");
mysql_select_db("work");
$sql="select * from work";
$open=mysql_query($sql);
$row=mysql_fetch_array($open);
if(!$row[id]){
echo"数据库为空"
}
else
{
while($rs=mysql_fetch_array($open))
{
echo "<option w_id=".$rs->w_id.">".$rs->w_name."</option>";
}}

Answer 3

$sql="select * from work";
$open=mysql_query($sql);
if(mysql_num_rows($open) < 1)
   echo "data is empty!";
else{
  while($rs=mysql_fetch_object($open))
    echo "<option w_id=".$rs->w_id.">".$rs->w_name."</option>";
}