determining if table has no record?

[coder9]

what commands i need to determine if the table has no record or empty?

 

thank you.

 

[trq]

<?php

  // connect to db.

  $sql = "SELECT foo FROM tbl";
  if ($result = mysql_query($sql)) {
    if (!mysql_num_rows($result)) {
      echo "Table is empty";
    }
  }

?>

[Barand]

More efficient to use COUNT

 

$res = mysql_query("SELECT COUNT(*) FROM table");
if (mysql_result($res,0)==0)
{
    // empty
}

[unkwntech]

I'll Second Barand on this.

[Third_Degree]

The battle of a 13,574 posts member and a 14,131 posts member 

 

But I, also, will go with Barand.

[trq]

I'm not going to argue, though I don't really see one being more efficient than the other. The both require the execution of one query and both use two function calls. Really wouldn't be much in it.

[Third_Degree]

I was too lazy to consult the php source on this one, but if I recall, mysql_num_rows() would actually be loading a new string/array engine to actually count the number of records, but I could be woefully wrong (I guess it would do this in mysql too, but as I said, I checked neither source). I guess the only way to test it would be a speed test of each script.

[Barand]

Count(*) only ever returns a single field no matter how many recs are in the file. If there were 1000 recs in the file, SELECT foo pulls a 1000 foos down just so you can call num_rows().

 

"SELECT COUNT(*) FROM tbl" is optimised so it doesn't even need to read the table, it just looks it up in its internal tables.

[trq]

Count(*) only ever returns a single field no matter how many recs are in the file. If there were 1000 recs in the file, SELECT foo pulls a 1000 foos down just so you can call num_rows().

 

"SELECT COUNT(*) FROM tbl" is optimised so it doesn't even need to read the table, it just looks it up in its internal tables.

 

That makes sense, you win