如何从带变量的日期获取日期名称

Question

i want to use the funtion DAYNAME, but will get this date from a form, and depends of the day of the week, the person who create the form will win more points

i think something like this

if ($row['DAYNAME($Data)'] == "Monday") {
$suma1=1;
} elseif ($row['DAYNAME($Data)'] == "Tuesday"){
    $suma1=1;
} elseif ($row['DAYNAME($Data)'] == "Wednesday"){
    $suma1=1;
} elseif ($row['DAYNAME($Data)'] == "Thursday"){
    $suma1=1;
} elseif ($row['DAYNAME($Data)'] == "Friday"){
    $suma1=1;
} elseif ($row['DAYNAME($Data)'] == "Saturday"){
    $suma1=2;
} elseif ($row['DAYNAME($Data)'] == "Sunday"){
    $suma1=2;
}

the problem is here

i have this...

 <?php
$db = "sp28";  
$dbh = new PDO("mysql:host=$hostname;dbname=$db", $username, $password);  
foreach($dbh->query('SELECT DAYNAME("2017-04-06")') as $row) {  
echo "<tr>";  
echo "<td>" . $row['DAYNAME("2017-04-06")'] . "</td>";   
echo "</tr>";  

but i want have like this, the variable in DAYNAME,but it doesnt work

<?php
$Data="2017-04-06";
$db = "sp28";  
$dbh = new PDO("mysql:host=$hostname;dbname=$db", $username, $password);  
foreach($dbh->query('SELECT DAYNAME("$Data")') as $row) {  
echo "<tr>";  
echo "<td>" . $row['DAYNAME("$Data")'] . "</td>";   
echo "</tr>";  

}
?>