PHP - Manual: mysql_list_fields

2024-11-14

mysql_list_fields

(PHP 4, PHP 5)

mysql_list_fields — 列出 MySQL 结果中的字段

说明

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

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()。

示例 #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。

注意:
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。

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User Contributed Notes 7 notes

down

mbevan at marginsoftware dot com ¶

18 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 ¶

17 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

-5

phpflow at gmail dot com ¶

9 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 ¶

19 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

-9

perwool at seznam dot cz ¶

14 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

-11

steve at tequilasolutions dot com ¶

15 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

-21

user1337 at 1337example dot com ¶

4 years ago


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官方地址：https://www.php.net/manual/en/function.mysql-list-fields.php

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mysql_list_fields

说明

User Contributed Notes 7 notes