mysql_fetch_array

(PHP 4, PHP 5)

mysql_fetch_array — Recupera una fila de resultados como un array asociativo, un array numérico o como ambos

Advertencia

Esta extensión fue declarada obsoleta en PHP 5.5.0 y eliminada en PHP 7.0.0. En su lugar debería utilzarse las extensiones MySQLi o PDO_MySQL. Véase también la guía MySQL: elegir una API. Las alternativas a esta función son:

Descripción

mysql_fetch_array(resource $result, int $result_type = MYSQL_BOTH): array

Devuelve un array que corresponde a la fila recuperada y mueve el puntero de datos interno hacia delante.

Parámetros

result: El resultado resource que está siendo evaluado. Este resultado proviene de una llamada a mysql_query().
result_type: El tipo de array que va a ser devuelto. Es una constante y puede tomar los siguientes valores: MYSQL_ASSOC, MYSQL_NUM, y MYSQL_BOTH.

Valores devueltos

Devuelve un array de cadenas que corresponde a la fila recuperada, o false si no hay más filas. El tipo del array retornado depende de como esté definido result_type. Al utilizar MYSQL_BOTH (predeterminado), se obtendrá un array con ambos índices: asociativos y numéricos. Al utilizar MYSQL_ASSOC, se obtienen solo los índices asociativos (tal como funciona mysql_fetch_assoc()). Al utilizar MYSQL_NUM, se obtienen solo los índices numéricos (tal como funciona mysql_fetch_row()).

Si dos o más columnas del resultado tienen el mismo nombre de campo, la última columna tomará precedencia. Para acceder a la/s otra/s columna/s con el mismo nombre, se deberá usar el índice numérico de la columna o crear un alias para la columna. Para las columnas con alias, no se puede acceder al contenido con el nombre de la columna original.

Ejemplos

Ejemplo #1 Consulta con nombres de campos duplicados con alias

SELECT tabla1.campo AS foo, tabla2.campo AS bar FROM tabla1, tabla2

Ejemplo #2 mysql_fetch_array() con MYSQL_NUM

<?php
mysql_connect("localhost", "usuario_mysql", "contraseña_mysql") or
    die("No se pudo conectar: " . mysql_error());
mysql_select_db("mibd");

$resultado = mysql_query("SELECT id, nombre FROM mitabla");

while ($fila = mysql_fetch_array($resultado, MYSQL_NUM)) {
    printf("ID: %s  Nombre: %s", $fila[0], $fila[1]);
}

mysql_free_result($resultado);
?>

Ejemplo #3 mysql_fetch_array() con MYSQL_ASSOC

<?php
mysql_connect("localhost", "usuario_mysql", "contraseña_mysql") or
    die("No se pudo conectar: " . mysql_error());
mysql_select_db("mibd");

$resultado = mysql_query("SELECT id, nombre FROM mitabla");

while ($fila = mysql_fetch_array($resultado, MYSQL_ASSOC)) {
    printf("ID: %s  Nombre: %s", $fila["id"], $fila["nombre"]);
}

mysql_free_result($resultado);
?>

Ejemplo #4 mysql_fetch_array() con MYSQL_BOTH

<?php
mysql_connect("localhost", "usuario_mysql", "contraseña_mysql") or
    die("No se pudo conectar: " . mysql_error());
mysql_select_db("mibd");

$resultado = mysql_query("SELECT id, nombre FROM mitabla");

while ($fila = mysql_fetch_array($resultado, MYSQL_BOTH)) {
    printf ("ID: %s  Nombre: %s", $fila[0], $fila["nombre"]);
}

mysql_free_result($resultado);
?>

Notas

Nota: Rendimiento

Una cosa importante a tener en cuenta es que el uso de mysql_fetch_array() no es significativamente más lento que el uso de mysql_fetch_row(), aunque provee un valor añadido considerable.

Nota: Los nombres de los campos devueltos por esta función son sensibles a mayúsculas y minúsculas.

Nota: Esta función define campos NULOS al valor null de PHP.

Ver también

mysql_fetch_row() - Obtiene una fila de resultados como un array numérico
mysql_fetch_assoc() - Recupera una fila de resultados como un array asociativo
mysql_data_seek() - Mueve el puntero de resultados interno
mysql_query() - Enviar una consulta MySQL

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User Contributed Notes 13 notes

down

robjohnson at black-hole dot com ¶

22 years ago

Benchmark on a table with 38567 rows:

mysql_fetch_array
MYSQL_BOTH: 6.01940000057 secs
MYSQL_NUM: 3.22173595428 secs 
MYSQL_ASSOC: 3.92950594425 secs 

mysql_fetch_row: 2.35096800327 secs 
mysql_fetch_assoc: 2.92349803448 secs 

As you can see, it's twice as effecient to fetch either an array or a hash, rather than getting both.  it's even faster to use fetch_row rather than passing fetch_array MYSQL_NUM, or fetch_assoc rather than fetch_array MYSQL_ASSOC.  Don't fetch BOTH unless you really need them, and most of the time you don't.

down

KingIsulgard ¶

15 years ago

I have found a way to put all results from the select query in an array in one line.

// Read records
$result = mysql_query("SELECT * FROM table;") or die(mysql_error());
    
// Put them in array
for($i = 0; $array[$i] = mysql_fetch_assoc($result); $i++) ;
    
// Delete last empty one
array_pop($array);

You need to delete the last one because this will always be empty.

By this you can easily read the entire table to an array and preserve the keys of the table columns. Very handy.

down

-4

puzbie at facebookanswers dot co dot uk ¶

12 years ago

<?php
 while($r[]=mysql_fetch_array($sql));
 ?>
 
Yes, that will generate a dummy array element containing the false of the final mysql_fetch_array. You should either truncate the array or (more sensibly in my mind) check that the result of mysql_fetch_array is not false before adding it to the array.

down

-3

info at o08 dot com ¶

15 years ago

As opposite of mysql_fetch_array:



<?php

function mysql_insert_array ($my_table, $my_array) { 

    $keys = array_keys($my_array); 

    $values = array_values($my_array); 

    $sql = 'INSERT INTO ' . $my_table . '(' . implode(',', $keys) . ') VALUES ("' . implode('","', $values) . '")';

    return(mysql_query($sql)); 

}

#http://www.weberdev.com/get_example-4493.html

?>

down

-5

final at skilled dot ch ¶

13 years ago

I ran into troubles with MySQL NULL values when I generated dynamic queries and then had to figure out whether my resultset contained a specific field.

First instict was to use isset() and is_null(), but these function will not behave as you probably expect.

I ended up using array_key_exists, as it was the only function that could tell me whether the key actually existed or not.

<?php
$row = mysql_fetch_assoc(mysql_query("SELECT null as a"));
var_dump($row); //array(1) {  ["a"]=>  NULL }
var_dump(isset($row['a'])); //false
var_dump(isset($row['b'])); //false
var_dump(is_null($row['a'])); //true
var_dump(is_null($row['b'])); //true + throws undefined index notice
var_dump(array_key_exists('a', $row)); // true
var_dump(array_key_exists('b', $row)); // false
?>

down

-4

john at skem9 dot com ¶

18 years ago

my main purpose was to show the fetched array into a table, showing the results side by side instead of underneath each other, and heres what I've come up with. 

just change the $display number to however many columns you would like to have, just dont change the $cols number or you might run into some problems.

<?php
$display = 4;
$cols = 0;
echo "<table>";
while($fetched = mysql_fetch_array($result)){
    if($cols == 0){
        echo "<tr>\n";
    }
    // put what you would like to display within each cell here
    echo "<td>".$fetched['id']."<br />".$fetched['name']."</td>\n";
    $cols++;
    if($cols == $display){
        echo "</tr>\n";
        $cols = 0;
    }
}
// added the following so it would display the correct html
if($cols != $display && $cols != 0){
    $neededtds = $display - $cols;
    for($i=0;$i<$neededtds;$i++){
        echo "<td></td>\n";
    }
     echo "</tr></table>"; 
    } else {
    echo "</table>";
}
?>

Hopefully this will save some of you a lot of searching.

any kind of improvements on this would be awesome!

down

-5

joey at clean dot q7 dot com ¶

20 years ago

The issue of NULL fields seems to not be an issue anymore (as of 4.2.2 at least).  mysql_fetch_* now seems to fully populate the array and put in entries with values of NULL when that is what the database returned.  This is certainly the behaviour I expected, so I was concerned when i saw the notes here, but testing shows it does work the way I expected.

down

-4

kunky at mail dot berlios dot de ¶

18 years ago

This is very useful when the following query is used:

`SHOW TABLE STATUS`

Different versions of MySQL give different responses to this.

Therefore, it is better to use mysql_fetch_array() because the numeric references given my mysql_fetch_row() give very different results.

down

-5

Anonymous ¶

13 years ago

If I use 

<?php
while($r[]=mysql_fetch_array($sql));
?>

so in array $r is one more entry then rows returned from the database.

down

-5

barbieri at NOSPAMzero dot it ¶

22 years ago

Here is a suggestion to workaround the problem of NULL values:

// get associative array, with NULL values set
$record = mysql_fetch_array($queryID,MYSQL_ASSOC);

// set number indices
if(is_array($record))
{
    $i = 0;
    foreach($record as $element)
        $record[$i++] = $element;
}

This way you can access $result array as usual, having NULL fields set.

down

-5

joelwan at gmail dot com ¶

19 years ago

Try Php Object Generator: http://www.phpobjectgenerator.com

It's kind of similar to Daogen, which was suggested in one of the comments above, but simpler and easier to use.

Php Object Generator generates the Php Classes for your Php Objects. It also provides the database class so you can focus on more important aspects of your project. Hope this helps.

down

-5

tim at wiltshirewebs dot com ¶

18 years ago

Here's a quick way to duplicate or clone a record to the same table using only 4 lines of code:

// first, get the highest id number, so we can calc the new id number for the dupe
// second, get the original entity
// third, increment the dupe record id to 1 over the max
// finally insert the new record - voila - 4 lines!

$id_max = mysql_result(mysql_query("SELECT MAX(id) FROM table_name"),0,0) or die("Could not execute query"); 
$entity = mysql_fetch_array(mysql_query("SELECT * FROM table." WHERE id='$id_original'),MYSQL_ASSOC) or die("Could not select original record"); // MYSQL_ASSOC forces a purely associative array and blocks twin key dupes, vitally, it brings the keys out so they can be used in line 4
$entity["id"]=$id_max+1; 
mysql_query("INSERT INTO it_pages (".implode(", ",array_keys($Entity)).") VALUES ('".implode("', '",array_values($Entity))."')");

Really struggled in cracking this nut - maybe there's an easier way out there?  Thanks to other posters for providing inspiration. Good luck - Tim

down

-5

some at gamepoint dot net ¶

22 years ago

I never had so much trouble with null fields but it's to my understanding that extract only works as expected when using an associative array only, which is the case with mysql_fetch_assoc() as used in the previous note.

However a mysql_fetch_array will return field values with both the numerical and associative keys, the numerical ones being those extract() can't handle very well.
You can prevent that by calling mysql_fetch_array($result,MYSQL_ASSOC) which will return the same result as mysql_fetch_assoc and is extract() friendly.

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