SunshinePHP Developer Conference 2015

mysqli_stmt::fetch

mysqli_stmt_fetch

(PHP 5)

mysqli_stmt::fetch -- mysqli_stmt_fetchObtiene los resultados de una sentencia preparadas en las variables vinculadas

Descripción

Estilo orientado a objetos

bool mysqli_stmt::fetch ( void )

Estilo por procedimientos

bool mysqli_stmt_fetch ( mysqli_stmt $stmt )

Obtiene los resultados de una sentencia preparadas en las variables vinculadas mediante mysqli_stmt_bind_result().

Nota:

Observe que todas las columnas deben estar vinculadas por la aplicación antes de llamar a mysqli_stmt_fetch().

Nota:

Los datos son transferidos sin almacenarlos en buffer sin llamar a mysqli_stmt_store_result(), la cual puede disminuir el rendimiento (pero reduce el coste de memoria).

Parámetros

stmt

Sólo estilo por procediminetos: Un identificador de declaraciones devuelto por mysqli_stmt_init().

Valores devueltos

Valores devueltos
Valor Descripción
TRUE Éxito. Los datos se han obtenido
FALSE Ocurrió un error
NULL No existen más filas/datos u ocurrió un truncamiento de los datos

Ejemplos

Ejemplo #1 Estilo orientado a objetos

<?php
$mysqli 
= new mysqli("localhost""mi_usuario""mi_contraseña""world");

/* comprobar la conexión */
if (mysqli_connect_errno()) {
    
printf("Falló la conexión: %s\n"mysqli_connect_error());
    exit();
}

$consulta "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5";

if (
$sentencia $mysqli->prepare($consulta)) {

    
/* ejecutar la sentencia */
    
$sentencia->execute();

    
/* vincular las variables de resultados */
    
$sentencia->bind_result($nombre$código);

    
/* obtener los valores */
    
while ($sentencia->fetch()) {
        
printf ("%s (%s)\n"$nombre$código);
    }

    
/* cerrar la sentencia */
    
$sentencia->close();
}

/* cerrar la conexión */
$mysqli->close();
?>

Ejemplo #2 Estilo por procedimientos

<?php
$enlace 
mysqli_connect("localhost""mi_usuario""mi_contraseña""world");

/* comprobar la conexión */
if (mysqli_connect_errno()) {
    
printf("Falló la conexión: %s\n"mysqli_connect_error());
    exit();
}

$consulta "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 150,5";

if (
$sentencia mysqli_prepare($link$consulta)) {

    
/* ejecutar la sentencia */
    
mysqli_stmt_execute($sentencia);

    
/* vincular las variables de resultados */
    
mysqli_stmt_bind_result($sentencia$nombre$código);

    
/* obtener los valores */
    
while (mysqli_stmt_fetch($sentencia)) {
        
printf ("%s (%s)\n"$nombre$código);
    }

    
/* cerrar la sentencia */
    
mysqli_stmt_close($sentencia);
}

/* cerrar la conexión */
mysqli_close($link);
?>

El resultado de los ejemplos serían:

Rockford (USA)
Tallahassee (USA)
Salinas (USA)
Santa Clarita (USA)
Springfield (USA)

Ver también

add a note add a note

User Contributed Notes 9 notes

up
4
Lyndon
6 years ago
This function uses the same idea as the last, but instead binds the fields to a given array.
<?php
function stmt_bind_assoc (&$stmt, &$out) {
   
$data = mysqli_stmt_result_metadata($stmt);
   
$fields = array();
   
$out = array();

   
$fields[0] = $stmt;
   
$count = 1;

    while(
$field = mysqli_fetch_field($data)) {
       
$fields[$count] = &$out[$field->name];
       
$count++;
    }   
   
call_user_func_array(mysqli_stmt_bind_result, $fields);
}

// example

$stmt = $mysqli->prepare("SELECT name, userid FROM somewhere");
$stmt->execute();

$row = array();
stmt_bind_assoc($stmt, $row);

// loop through all result rows
while ($stmt->fetch()) {
   
print_r($row);
}
?>
up
6
Bruce Martin
2 years ago
I was trying to use a generic select * from table statment and have the results returned in an array. I finally came up with this solution, others have similar solutions, but they where not working for me.
<?php
   
//Snip use normal methods to get to this point
   
$stmt->execute();
   
$metaResults = $stmt->result_metadata();
   
$fields = $metaResults->fetch_fields();
   
$statementParams='';
    
//build the bind_results statement dynamically so I can get the results in an array
    
foreach($fields as $field){
         if(empty(
$statementParams)){
            
$statementParams.="\$column['".$field->name."']";
         }else{
            
$statementParams.=", \$column['".$field->name."']";
         }
    }
   
$statment="\$stmt->bind_result($statementParams);";
    eval(
$statment);
    while(
$stmt->fetch()){
       
//Now the data is contained in the assoc array $column. Useful if you need to do a foreach, or
        //if your lazy and didn't want to write out each param to bind.
   
}
   
// Continue on as usual.
?>
up
2
andrey at php dot net
9 years ago
IMPORTANT note: Be careful when you use this function with big result sets or with BLOB/TEXT columns. When one or more columns are of type (MEDIUM|LONG)(BLOB|TEXT) and ::store_result() was not called mysqli_stmt_fetch() will try to allocate at least 16MB for every such column. It _doesn't_ matter that the longest value in the result set is for example 30 bytes, 16MB will be allocated. Therefore it is not the best idea ot use binding of parameters whenever fetching big data. Why? Because once the data is in the mysql result set stored in memory and then second time in the PHP variable.
up
2
dan dot latter at gmail dot com
7 years ago
The following function taken from PHP Cookbook 2, returns an associative array of a row in the resultset, place in while loop to iterate through whole result set.

<?php
public function fetchArray () {
  
$data = mysqli_stmt_result_metadata($this->stmt);
       
$fields = array();
       
$out = array();

       
$fields[0] = &$this->stmt;
       
$count = 1;

        while(
$field = mysqli_fetch_field($data)) {
           
$fields[$count] = &$out[$field->name];
           
$count++;
        }
       
       
call_user_func_array(mysqli_stmt_bind_result, $fields);
       
mysqli_stmt_fetch($this->stmt);
        return (
count($out) == 0) ? false : $out;

    }
?>
up
2
php at johnbaldock dot co dot uk
7 years ago
Having just learned about call_user_func_array I reworked my fetch_assoc example. Swapping the following code makes for a more elegant (and faster) solution.

Using:
<?php
while ($columnName = $meta->fetch_field()) {
   
$columns[] = &$results[$columnName->name];
}       
call_user_func_array(array($stmt, 'bind_result'), $columns);
?>

Instead of this code from my example below:
<?php
$bindResult
= '$stmt->bind_result(';
while (
$columnName = $meta->fetch_field()) {
  
$bindResult .= '$results["'.$columnName->name.'"],';
}
$bindResult = rtrim($bindResult, ',') . ');';
eval(
$bindResult);
?>

The full reworked fetch_assoc code for reference:
<?php
$mysqli
= new mysqli($dbHost, $dbUsername, $dbPassword, $dbDatabase);
$stmt = $mysqli->prepare('select * from foobar');
$stmt->execute();
$stmt->store_result();
$meta = $stmt->result_metadata();

while (
$column = $meta->fetch_field()) {
  
$bindVarsArray[] = &$results[$column->name];
}       
call_user_func_array(array($stmt, 'bind_result'), $bindVarsArray);

$stmt->fetch();

echo
var_dump($results);
// outputs:
//
// array(3) {
//  ["id"]=>
//  &int(1)
//  ["foo"]=>
//  &string(11) "This is Foo"
//  ["bar"]=>
//  &string(11) "This is Bar"
// }
?>
up
1
denath2 at yahoo dot com
6 years ago
As php at johnbaldock dot co dot uk mentioned the problem is that the $row returned is reference and not data. So, when you write  $array[] = $row, the $array will be filled up with the last element of the dataset. To come up with this you can write the following hack:

// loop through all result rows
while ($stmt->fetch()) {

    foreach( $row as $key=>$value )
    {
        $row_tmb[ $key ] = $value;
    }
    $array[] = $row_tmb;
   
}
up
0
piedone at pyrocenter dot hu
6 years ago
I tried the mentioned stmt_bind_assoc() function, but somehow, very strangely it doesn't allow the values to be written in an array! In the while loop, the row is fetched correctly, but if I write $array[] = $row;, the array will be filled up with the last element of the dataset... Unfortunately I couldn't find a solution.
up
0
Typer85 at gmail dot com
7 years ago
Just a side note,

I see many people are contributing in ways to help return result sets for prepared statements in ASSOSITAVE arrays the same as the mysqli_fetch_assos function might return from a normal query issued via mysqli_query.

This is done, in all the examples I have seen, by dynamically getting the field names in the prepared statement and binding them using 'variable' variables, which are variables that are created dynamically with the name of the field names.

Some thing though you should take into consideration is illegal variable names in PHP. Assume that you have a field name in your database table named 'My Field' , notice the space between 'My' and 'Field'.

To dynamically create this variable is illegal in PHP as variables can not have spaces in them. Furthermore, you won't be able to access the binded data as you can not reference a variable like so:

<?php

// Syntax Error.

echo $My Table;

?>

The only suitable solution I find now is to replace all spaces in a field name with an underscore so that you can use the binded variable like so:

<?php

// This Works.

echo $My_Table;

// Notice the space is now replaced with an underscore.

?>

All you simply have to do is before you dynamically bind the data, so a string search for any spaces in the table name, replace them with an underscore, THEN bind the variable.

That way you should not run into problems.
up
-1
php at johnbaldock dot co dot uk
7 years ago
I wanted a simple way to get the equivalent of fetch_assoc when using a prepared statement. I came up with the following:

<?php
$mysqli
= new mysqli($dbHost, $dbUsername, $dbPassword, $dbDatabase);
$stmt = $mysqli->prepare('select * from foobar');
$stmt->execute();
$stmt->store_result();
$meta = $stmt->result_metadata();

// the following creates a bind_result string with an argument for each column in the query
// e.g. $stmt->bind_result($results["id"], $results["foo"], $results["bar"]);
$bindResult = '$stmt->bind_result(';
while (
$columnName = $meta->fetch_field()) {
   
$bindResult .= '$results["'.$columnName->name.'"],';
}
$bindResult = rtrim($bindResult, ',') . ');';

// executes the bind_result string
eval($bindResult);
$stmt->fetch();

echo
var_dump($results);
// outputs:
//
// array(3) {
//   ["id"]=>
//   &int(1)
//   ["foo"]=>
//   &string(11) "This is Foo"
//   ["bar"]=>
//   &string(11) "This is Bar"
// }
?>
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