使用PDO进行左连接

Question

I am using the following PDO query:

  <?php
            $cadena =   $_SESSION[Region];

// We Will prepare SQL Query


       $STM = $dbh->prepare("SELECT  `id_mesero`, `nombre_mesero`,`alias_mesero`, `rest_mesero` FROM tbmeseros WHERE cadena_mesero='$cadena'");
// For Executing prepared statement we will use below function
    $STM->execute();
// we will fetch records like this and use foreach loop to show multiple Results
    $STMrecords = $STM->fetchAll();
    foreach($STMrecords as $row)
        {

The value from the 'rest_mesero' field is the index from the table 'tbrestaurantes'.

I would need to join some fields values from 'tbrestaurantes' to the PDO query, but I don't know how to do it using PDO.

Any help is welcome.

UPDATED QUESTION TEXT

This is my proposal for the query :

$dbh->prepare("SELECT * FROM tbmeseros LEFT JOIN tbrestaurantes ON tbmeseros.rest_mesero = tbrestaurantes.id_restaurante WHERE tbmeseros.cad_mesero = ?");

But is show an error:

Warning: PDOStatement::execute() [pdostatement.execute]: SQLSTATE[HY093]: Invalid parameter number: no parameters were bound in /.../AdminMeseros.php on line 80

Line 80 is

$STM->execute();

This is my updated query:

              <?php
            $cadena =   $_SESSION[Region];



       $STM =$dbh->prepare("SELECT * FROM tbmeseros LEFT JOIN tbrestaurantes ON tbmeseros.rest_mesero = tbrestaurantes.id_restaurante WHERE tbmeseros.cad_mesero = ?");
       $STM->bindParam(1, $cadena);
// For Executing prepared statement we will use below function
    $STM->execute(array($cadena));
// we will fetch records like this and use foreach loop to show multiple Results
    $STMrecords = $STM->fetchAll();
    foreach($STMrecords as $row)
        {

And here table's screenshots:

For tbmeseros:

For tbrestaurantes:

The value of $cadena is 'HQ3'.

Answer 1

When you put a parameter in the SQL, you need to supply the value for the parameter. There are two ways to do that:

1) Call bindParam():

$STM->bindParam(1, $cadana);

2) Provide the values when calling execute():

$STM->execute(array($cadana));