Veo que miarroba no soporta Procedimientos Almacenados (Store Procedure Language). Podeis Confirmar ?

Intentado el siguiente, pero no veo que no se almacen, luego no es ejecutable desde PHP::

    // MyDistance-----------------------------------------------------------------MyDistance
    $spl0 = "DROP FUNCTION IF EXISTS MyDistance ";
    $spl1 = "CREATE FUNCTION MyDistance(lat1 DOUBLE, lng1 DOUBLE, lat2 DOUBLE, lng2 DOUBLE) ";
    $spl1 = $spl1."RETURNS VARCHAR(12) ";
    $spl1 = $spl1."BEGIN ";
    
    //$km = 111.302;        $degtorad = 0.01745329;                $radtodeg = 57.29577951; 
    $spl1 = $spl1."DECLARE KM DOUBLE; ";        
    $spl1 = $spl1."DECLARE DEGTORAD DOUBLE; ";    
    $spl1 = $spl1."DECLARE RADTODEG DOUBLE; ";    
    $spl1 = $spl1."DECLARE DLONG DOUBLE; ";
    $spl1 = $spl1."DECLARE DVALUE DOUBLE; ";    
    $spl1 = $spl1."DECLARE DD DOUBLE; ";
    $spl1 = $spl1."DECLARE RESULT VARCHAR(12); ";
    
    $spl1 = $spl1."SET KM = 111.302; ";                            // EL ORDEN ES IMPRTANTE
    $spl1 = $spl1."SET DEGTORAD = 0.01745329; ";
    $spl1 = $spl1."SET RADTODEG = 57.29577951; ";
    
    //$dlong = ($long1 - $long2); 
    $spl1 = $spl1."SET DLONG = lng1 - lng2; ";
    
    //$dvalue = (sin($lat1 * $degtorad) * sin($lat2 * $degtorad)) + (cos($lat1 * $degtorad) * cos($lat2 * $degtorad) * cos($dlong * $degtorad)); 
    $spl1 = $spl1."SET DVALUE = (SIN(lat1 * DEGTORAD) * SIN(lat2 * DEGTORAD)); ";
    $spl1 = $spl1."SET DVALUE = DVALUE + (COS(lat1 * DEGTORAD) * COS(lat2 * DEGTORAD) * COS(DLONG * DEGTORAD)); ";
    
    //$dd = acos($dvalue) * $radtodeg; 
    $spl1 = $spl1."SET DD = ACOS(DVALUE) * RADTODEG; ";
    
    //return round(($dd * $km), 2);    
    $spl1 = $spl1."SET RESULT = CONCAT(ROUND((DD * KM), 3) , ' Km'); ";     // number_format($row['MiAvg'], 3, '.', '');
    $spl1 = $spl1."RETURN RESULT; ";    
    
    $spl1 = $spl1."END; ";
    
    if ( !mysqli_query($link, $spl0) ) {
        echo "User Defined Function failed: <br>(" . mysqli_errno($link) . ") " . mysqli_error($link) ."<br>"; } 

    
    if ( !mysqli_query($link, $spl1) ) {
        echo "User Defined Function failed: <br>(" . mysqli_errno($link) . ") " . mysqli_error($link) ."<br>"; }