two consecutive selections

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two consecutive selections

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#1 by (1 votes)

1

I need to do this exercise in a single file and only with php. I have two combobox with two buttons, one behind each combo. The first combo loads well from a mysql table. When the first button is clicked, the second combo is loaded with a query that is created with the choice of the first one and when the second button is clicked, a table with data from the database appears. The problem is that it does not save the variables that I select in the combos when I hit the buttons. This is the code that I have done so far.

<html>
    <head>
        <title>WORLD</title>
    </head>
    <body>
        <?php
            define("SERVIDOR","localhost");
            define("USUARIO","root");
            define("CLAVE","");
            $BD="world";
            $db;
            try{
                if($BD!='')
                    $db=new PDO("mysql:host=".SERVIDOR.";dbname=".$BD.";charset=utf8",USUARIO,CLAVE,array(PDO::MYSQL_ATTR_INIT_COMMAND=>"SET NAMES 'utf8'"));
                else
                    $db=new PDO("mysql:host=".SERVIDOR.";charset=utf8",USUARIO,CLAVE,array(PDO::MYSQL_ATTR_INIT_COMMAND=>"SET NAMES 'utf8'"));
                $db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY,true);
                $db->setAttribute(PDO::NULL_TO_STRING,true);
                if($BD==''){
                    $sql=file_get_contents('world.sql');
                    $this->ejecuta_SQL($sql);
                }
            }catch(PDOException $e){
                die("<p><h3>No se ha podido establecer la conexión.
                    <p>Compruebe si está activado el servidor de bases de
                    datos MySQL.</h3></p>\n<p>Error: ".$e->getMessage()."</p>\n");
            }
            $region="";
            $name="";
            echo "<h1>EJERCICIO CONSULTA DE PAISES POR REGIONES</h1>
                <form name='form1' method='post' action=\"index.php\">";
            $sql1='SELECT Region FROM country';
            $resultado1=$db->query($sql1);
            echo "Selecciona Region: <select name='campo_busqueda1'>
                <option>Selecciona...</option>";
            while(($fila1=$resultado1->fetch(PDO::FETCH_ASSOC))!=NULL){
                echo '<option value="'.$fila1["Region"].'">'.$fila1["Region"].'</option>';
            };
            $region=$_POST['campo_busqueda1'];
            //$region=isset($_POST["campo_busqueda1"]) ? $_POST["campo_busqueda1"] : "";
            echo "</select>";
            echo "<input type='submit' value='Enviar'><br>";
            $sql2='SELECT Name FROM country WHERE Region="'.$region.'"';
            $resultado2=$db->query($sql2);
            echo "Selecciona Pais: <select name='campo_busqueda2'>
                <option>Selecciona...</option>";
            while(($fila2=$resultado2->fetch(PDO::FETCH_ASSOC))!=NULL){
                echo '<option value="'.$fila2["Name"].'">'.$fila2["Name"].'</option>';
            };
            $name=$_POST['campo_busqueda2'];
            //$name=isset($_POST["campo_busqueda2"]) ? $_POST["campo_busqueda2"] : "";
            echo "</select>";
            echo "<input type='submit' value='Enviar'><br>
            </form>";
        ?>
        <table border=1>
            <tr>
                <th>Nombre</th>
                <th>Poblacion</th>
            </tr>
                <?php
                    $sql3='SELECT city.Name,city.Population FROM city as city INNER JOIN country AS country ON city.CountryCode=country.Code
                        WHERE (country.Region="'.$region.'") AND (country.Name="'.$name.'")';
                    $resultado3=$db->query($sql3);
                    echo $region;
                    echo $name;
                    echo $resultado3;
                    while($row=$resultado3->fetch(PDO::FETCH_ASSOC)){
                        echo $row;
                        print_r($row);
                        echo '<tr><td>'.$row[0].'</td><td>'.$row[1].'</td></tr>';
                    }
                ?>
        </table>
    </body>
</html>

mysql html php

asked by Charly Utrilla 23.12.2018 в 16:38

source

1 answer

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score 1 · Accepted Answer

To determine the selected option you must use the information stored in the post, what you can do is ask if it exists and if it matches the option marked as selected. To do this, you change the variable in which you collect the value of the post before the select. I'll give you an example with the first select, you should do the same in the second.

$sql1='SELECT Region FROM country';
$resultado1=$db->query($sql1);
$region=$_POST['campo_busqueda1'];
echo "Selecciona Region: <select name='campo_busqueda1'>
    <option>Selecciona...</option>";
    while(($fila1=$resultado1->fetch(PDO::FETCH_ASSOC))!=NULL){  
       if ($region && $fila1["Region"]==$region) { $seleccionado="selected"; } else {$seleccionado ="";}
       echo '<option value="'.$fila1["Region"].'" '.$seleccionado.'>'.$fila1["Region"].'</option>';
                };