MySQL 函数
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mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fields — 列出 MySQL 结果中的字段

说明

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

mysql_list_fields() 取得给定表名的信息。参数是数据库名和表名。返回一个结果指针，可以用于 mysql_field_flags()，mysql_field_len()，mysql_field_name() 和 mysql_field_type()。

Example #1 mysql_list_fields() 例子

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');

$fields = mysql_list_fields("database1", "table1", $link);
$columns = mysql_num_fields($fields);

for ($i = 0; $i < $columns; $i++) {
    echo mysql_field_name($fields, $i) . "\n";
}

以上例子将产生如下输出： 

field1
field2
field3
...

为向下兼容仍然可以使用 mysql_listfields()，但反对这样做。

Note:

mysql_list_fields() 函数已过时。最好用 mysql_query() 来发出一条 SHOW COLUMNS FROM table [LIKE 'name'] 的 SQL 语句来代替。

MySQL 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 列出 MySQL 结果中的字段

用户评论:

perwool at seznam dot cz (29-Oct-2007 10:32)

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

steve at tequilasolutions dot com (12-Sep-2006 02:33)

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

rhyous at yahoo dot com (04-Jun-2005 11:22)

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)

<?php
$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$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.

<?php
$qColumnNames = mysql_query("SHOW COLUMNS FROM table1",$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:

<?php
$row = mysql_fetch_row("SELECT * from table1",$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 09:40)

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 03:55)

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.