mysql_num_rows allways returns 0

Anon

Hi All:
I am a newbie to Mysql,I used a "select * " query to retrieve information from my mysql database,and use the function Mysql_num_rows($rs) to get the number of rows of result.but the function allway return 0.what is the reason ? is that it need some configuration in php.ini ?.
By the way,I used Mysql_result($rs,$rownum,"$filedname") to retrieve a cell data.but the system say it can not jump to the row .
Did anyone has similar problem?
I will greatly appreciate if some one can give me a clue.

Thanx.
Barry Lee.
Lijiang,China.

Anon

you need to phrase your select statement like this: "select * from your_table". MySQL doesn't know what table you are trying to select data from. One thing I do that helps with tracking down database errors is this:

$results = mysql_query("select * from my_table") or die(mysql_error());

The 'or die(mysql_error())' will output database errors if they occur. Hope this helps.

Anon

Hi,Aaron,
thank u for your help,but it is not a problem on table name,every thing is OK(I did a lot experiment),I want to input a sql statement from a form,and let the PHP do the query and generate the data listing.I input some sql like inserting and alter table,all works well.but when I select something,the fieldnum is allways 1,and when I want to repeat by:
for ($i=0;$i<$rownum;$i++),it give nothing.
can u give me more suggestion?.
the code is following:
the fields name heading is fine.but only a heading,now data below.
{
$rs=mysql_query($sql,$conn);
echo $sql." OK !!<hr color=red>";
$rownum=mysql_num_rows($rs);
$fieldnum=mysql_num_fields($rs);
echo "fields num is ".$fieldnum;
echo "<br>row nums is:".$rownum;
echo "<table cellspacing=0 border=1 bordercolor=blue><tr>";
for($i=0;$i<=($fieldnum-1);$i++)
{echo "<td>".mysql_field_name($rs,$i)."</td>";}
echo "</tr>";
$i=0;
while ($i<$rownum)
{echo "<tr>";
for ($j=0;$j<=($fieldnum-1);$j++)
{ echo "<td>";
$fieldname=mysql_field_name($rs,$j);
echo mysql_result($rs,$i,$fieldname);
echo "</td>";
}
echo "</tr>";
$i++;
}

 echo "</table>";
}

Barry Lee.
Lijiang,China

Anon

If Mysql_num_rows() returns 0, that means your query did not return any results.

Do you get any results in you run the query manally?