如何更改mysql数据的颜色？

This is my code :

echo "<td>".$row['Alpha']."</td>";

echo "<td>".$row['Beta']."</td>";

I want to show if $row['Alpha'] is <=100 , then color that value with red ,else if $row['Alpha']>100 then to color that value with black .And same for $row['Beta'].

This should work for you:

echo "<td style='color:" . ($row['Alpha'] <= 100 ? "red;": "black;") . "'>" . $row['Alpha'] . "</td>";
echo "<td style='color:" . ($row['Beta'] <= 100 ? "red;": "black;") . "'>" . $row['Beta'] . "</td>";

then

if($row['Alpha'] <= 100) {
  echo '<span style="color:red;">'.$row['Alpha'].'</span>';
}
else{
  echo '<span style="color:black;">'.$row['Alpha'].'</span>';
}
// so on for beta

if ($row['Alpha'] <= 100) $color = 'red';
if ($row['Alpha'] > 100) $color = 'black';
if ($row['Beta'] <= 100) $color = 'red';
if ($row['Beta'] > 100) $color = 'black';

echo "<span style=\"color: $color;\">This text is colored.</span>";

Just like this?

if ($row['Alpha'] <= 100)
    echo "<td style='color:red;'>".$row['Alpha']."</td>";
else
    echo "<td style='color:black;'>".$row['Alpha']."</td>";

You can use the code:

<?php
   //connection to the database and execution of the query
   if($row['Alpha'] <= 100){
      echo "<td style=\"color:#F00\>" . $row['Alpha'] . "</td>";
   }
   else{ 
      echo "<td style=\"color:#000\">" . $row['Alpha'] . "</td>";
   }
   if($row['Beta'] <= 100){
      echo "<td style=\"color:#F00\>" . $row['Beta'] . "</td>";
   }
   else{ 
      echo "<td style=\"color:#000\">" . $row['Beta'] . "</td>";
   }
?>

<style type="text/css">
.warning {
    color: red;
}
</style>

echo '<td' . ($row['x'] <= 100? ' class="warning"': '') . '>' . htmlentities($row['x']) . '</td>';