mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fields — List MySQL table fields

Description

resource mysql_list_fields ( string $database_name , string $table_name [, resource $link_identifier ] )

Retrieves information about the given table name.

This function is deprecated. It is preferable to use mysql_query() to issue a SQL SHOW COLUMNS FROM table [LIKE 'name'] statement instead.

Parameters

database_name: The name of the database that's being queried.
table_name: The name of the table that's being queried.
link_identifier: The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If by chance no connection is found or established, an E_WARNING level error is generated.

Return Values

A result pointer resource on success, or FALSE on failure.

The returned result can be used with mysql_field_flags(), mysql_field_len(), mysql_field_name() and mysql_field_type().

Examples

Example #1 Alternate to deprecated mysql_list_fields()


<?php
$result = mysql_query("SHOW COLUMNS FROM sometable");
if (!$result) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}
if (mysql_num_rows($result) > 0) {
    while ($row = mysql_fetch_assoc($result)) {
        print_r($row);
    }
}
?>

The above example will output something similar to:

Array
(
    [Field] => id
    [Type] => int(7)
    [Null] =>  
    [Key] => PRI
    [Default] =>
    [Extra] => auto_increment
)
Array
(
    [Field] => email
    [Type] => varchar(100)
    [Null] =>
    [Key] =>
    [Default] =>
    [Extra] =>
)

Notes

Note: For backward compatibility, the following deprecated alias may be used: mysql_listfields()


Every my html table output begins with heading row containing the field names. For that purpose I accepted the short combination of MySQL function, giving me a result similar to the mysql_fetch_array() for the row of values. The following example shows the basic idea. It should be adapted for the specific use:



<?php 

//...

$field_names = array_keys( mysql_fetch_array( mysql_query( $query, $link), MYSQL_ASSOC)); 

//...

?>



The advantage of this is, that it gives the names of the result, neither the field names of the whole table. 

Please read the discussion about duplicate field names in SQL result carefully. The use, as shown in the example above, increments the pointer, hence some regular function, which does not, could be more useful :-) 



Jan

khashmeshab at yahoo dot co dot uk
12-Sep-2007 11:48


You can use this SQL command instead of 'SHOW FIELDS FROM tablename;':

'DESC tablename;'

steve at tequilasolutions dot com
12-Sep-2006 03:33


Note, using mysql_list_fields will change the currently selected database so subsequent mysql_query operations will be on the database in param 1 not the one selected with mysql_select_db

arster
15-Oct-2005 09:05


# This should also give you an array of column names

$res = mysql_query("SHOW COLUMNS FROM `my_table`");

while ($row = mysql_fetch_array($res)) $col_names[]=$row[0];

harryzhong at hotmail dot com
26-Jul-2005 06:27


Here is a simple script get names of columns in an array:



//Get names of columns in table

$field_names = array();

$res = mysql_query("SHOW COLUMNS FROM `my_table`");

for($i=0;$i<mysql_num_rows($res);$i++){

    array_push($field_names,mysql_result($res, $i));

}

rhyous at yahoo dot com
05-Jun-2005 12:22


To make an array containing the names of a column from a table, you use the following simple script: (Note: using table1 with three columns)



$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$db) or die("mysql error");

$numColumns = mysql_num_rows($qColumnNames);

$x = 0;

while ($x < $numColumns)

{

    $colname = mysql_fetch_row($qColumnNames);

    $col[$colname[0]] = $colname[0];

    $x++;

}



print_r($col);



/* it will have the following output

Array (

[firstcolumn] => firstcolumn

[secondcolumn] => secondcolumn

[thirdcolumn] => thirdcolumn

)

*/



Or you can number the columns from zero.  This help when using it in conjunction with mysql_fetch_row to get an array.  You don't have to remember which number of the array a certain column is.



$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$db) or die("mysql error");

$numColumns = mysql_num_rows($qColumnNames);

$x = 0;

while ($x < $numColumns)

{

    $colname = mysql_fetch_row($qColumnNames);

    $col[$colname[0]] = $x;

    $x++;

}



print_r($col);



/* it will have the following output

Array (

[firstcolumn] => 0

[secondcolumn] => 1

[thirdcolumn] => 2

)

*/



To use it in conjuction with mysql_fetch_row:



$row = mysql_fetch_row("SELECT * from table1",$db) or die("mysql error");



You can now call $row[col[firstcolumn]].  This becomes useful when you have a lot of columns.

mbevan at marginsoftware dot com
13-Nov-2003 10:40


If you're willing to use a lot of functions to get a little information about fields in a table, this function is for you.  If you just want to get all the information you can find, you can use this:



<?php



// Taken from: http://ca.php.net/manual/en/function.mysql-field-flags.php

// Original by: amir at scrounch dot com

// Returns the name of the fields in the primary key for a table.

// Also keeps the fields in KEY order.  Handy.

function getPrimaryKeyOf($table) { 

  $keys = Array();



  $query = sprintf("SHOW KEYS FROM `%s`", $table);

  $result = mysql_query($query) or die(mysql_error());



  while ($row = mysql_fetch_assoc($result)) {

    if ( $row['Key_name'] == 'PRIMARY' )

      $keys[$row['Seq_in_index'] - 1] = $row['Column_name'];

  }



  return $keys;

}



// Returns a bunch of information about a table...

// The name of the auto-increment field, if any, fields in the

// primary key (using the function above), and all information

// about all fields.

function getTableInformationOf($table) {

  $information = array(

      "auto"    => "",

      "primary" => array(),

      "fields"  => array()

    );



  $information['primary'] = $this->getPrimaryKeyOf($table);



  $result = mysql_query("DESC `$table`");

  while ( $field = mysql_fetch_assoc($result) ) {

    $information['fields'][] = $field;

    if ( $field['Extra'] == "auto_increment" )

      $information['auto'] = $field['Field'];

  }



  return $information;

}



?>

dom at brainwaveuk dot com
19-Jul-2002 04:55


mysql_list_fields() retrieves information about the given table name but you can use something like mysql_fetch_field to retrieve the field names from a result source.

add a note

mysql_list_processes

mysql_list_dbs

Last updated: Fri, 09 Jan 2009