benchmarks for conditional existance

<pre><?php

$c = mysql_connect('localhost', 'root', '');

if(!$c) die('!');
echo mysql_select_db('test', $c)?'Connection':'Failure';
echo PHP_EOL;

echo ':::::::::::::::::::::::::BEGINNING NON-EXISTING TABLE::::::::::::::::::::::::::::::';
$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    mysql_query( 'SELECT 1 FROM foo' );
}
$end = microtime(1);

echo  ($end - $start) . " for bad select";
echo PHP_EOL;

$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SELECT table_name FROM information_schema.tables WHERE table_schema = 'test' AND table_name = 'foo';");
    if( $q ) $r = mysql_num_rows($q);
}
$end = microtime(1);

echo  ($end - $start) . " for select from schema num rows";

echo PHP_EOL;
$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SELECT table_name FROM information_schema.tables WHERE table_schema = 'test' AND table_name = 'foo';");
    if( $q ) $r = mysql_fetch_row($q);
}
$end = microtime(1);

echo  ($end - $start) . " for select from schema fetch row";

echo PHP_EOL;

$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SHOW TABLES FROM test");
    while( $r = mysql_fetch_array($q) )
    {
        if($r['Tables_in_test'] == 'foo') break;
    }
}
$end = microtime(1);

echo  ($end - $start) . " for SHOW TABLES FROM test";

echo PHP_EOL;
echo ':::::::::::::::::::::::::BEGINNING EXISTING TABLE::::::::::::::::::::::::::::::';
echo PHP_EOL;
$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    mysql_query( 'SELECT 1 FROM bar' );
}
$end = microtime(1);

echo  ($end - $start) . " for good select";

echo PHP_EOL;
$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SELECT table_name FROM information_schema.tables WHERE table_schema = 'test' AND table_name = 'bar';");
    if( $q ) $r = mysql_num_rows($q);
}
$end = microtime(1);

echo  ($end - $start) . " for select from schema num rows";
echo PHP_EOL;

$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SELECT table_name FROM information_schema.tables WHERE table_schema = 'test' AND table_name = 'bar';");
    if( $q ) $r = mysql_fetch_row($q);
}
$end = microtime(1);

echo  ($end - $start) . " for select from schema fetch row";
echo PHP_EOL;


$start = microtime(1);
for( $i = 0; $i < 100000; $i++ )
{
    $q = mysql_query("SHOW TABLES FROM test");
    while( $r = mysql_fetch_array($q) )
    {
        if($r['Tables_in_test'] == 'bar') break;
    }
}
$end = microtime(1);

echo  ($end - $start) . " for SHOW TABLES FROM test";
echo PHP_EOL;