mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fields — 列出 MySQL 表字段

警告

本函数自 PHP 5.4.0 起已废弃，并且它和整个MySQL 扩展自 PHP 7.0.0 开始被移除。可以选择出于活跃开发中的MySQLi或PDO_MySQL扩展来作为替代。参见MySQL：选择 API 指南来获取更多信息。用以替代本函数的有：

SQL 查询：SHOW COLUMNS FROM sometable

说明

mysql_list_fields(string $database_name, string $table_name, resource $link_identifier = NULL): resource

检索指定表名的信息。

此函数已弃用。最好使用 mysql_query() 发出 SQL SHOW COLUMNS FROM table [LIKE 'name'] 语句代替。

参数

database_name: The name of the database that's being queried.
table_name: The name of the table that's being queried.
link_identifier: MySQL 连接。如不指定连接标识，则使用由 mysql_connect() 最近打开的连接。如果没有找到该连接，会尝试不带参数调用 mysql_connect() 来创建。如没有找到连接或无法建立连接，则会生成 E_WARNING 级别的错误。

返回值

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

结果指针，可以用于 mysql_field_flags()、mysql_field_len()、mysql_field_name() 和 mysql_field_type()。

示例

示例 #1 替代弃用 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);
    }
}
?>

以上示例的输出类似于：

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

注释

注意:
为了向下兼容，可以使用下列已废弃的别名： mysql_listfields()

参见

mysql_field_flags() - 从结果中取得和指定字段关联的 flags
mysql_info() - 获取最近查询的有关信息

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User Contributed Notes 7 notes

down

mbevan at marginsoftware dot com ¶

20 years ago

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;
}

?>

down

rhyous at yahoo dot com ¶

18 years ago

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.

down

-3

phpflow at gmail dot com ¶

11 years ago

Below script is used to get all coloumn indormation of an table.When we are working custome ORM then we need to match the coloumn name with array keys.



<?php

function getColoumn($table) {

     $result = mysql_query("SHOW COLUMNS FROM ". $table);

      if (!$result) {

        echo 'Could not run query: ' . mysql_error();

      }

      $fieldnames=array();

      if (mysql_num_rows($result) > 0) {

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

          $fieldnames[] = $row['Field'];

        }

      }



      return $fieldnames;

}

?>

down

-6

dom at brainwaveuk dot com ¶

21 years ago

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.

down

-8

perwool at seznam dot cz ¶

16 years ago

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

down

-13

steve at tequilasolutions dot com ¶

17 years ago

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

down

-29

user1337 at 1337example dot com ¶

6 years ago

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