mysql_fetch_assoc()

(PHP 4 >= 4.0.3, PHP 5)

从结果集中取得一行作为关联数组

Warning

本扩展自 PHP 5.5.0起已废弃，并在自 PHP 7.0.0 开始被移除。应使用MySQLi或PDO_MySQL扩展来替换之。参见MySQL：选择 API指南以及相关 FAQ来获取更多信息。用以替代本函数的有：

• mysqli_fetch_assoc()
• PDOStatement::fetch(PDO::FETCH_ASSOC)

说明

mysql_fetch_assoc(resource $result): array

返回对应结果集的关联数组，并且继续移动内部数据指针。mysql_fetch_assoc()和用mysql_fetch_array()加上第二个可选参数 MYSQL_ASSOC 完全相同。它仅仅返回关联数组。

参数

$result

resource型的结果集。此结果集来自对mysql_query()的调用。

返回值

返回根据从结果集取得的行生成的关联数组；如果没有更多行则返回FALSE。

如果结果中的两个或以上的列具有相同字段名，最后一列将优先。要访问同名的其它列，要么用mysql_fetch_row()来取得数字索引或给该列起个别名。参见mysql_fetch_array()例子中有关别名说明。

范例

Example #1 扩展的mysql_fetch_assoc()例子

<?php
$conn = mysql_connect("localhost", "mysql_user", "mysql_password");
if (!$conn) {
    echo "Unable to connect to DB: " . mysql_error();
    exit;
}
  
if (!mysql_select_db("mydbname")) {
    echo "Unable to select mydbname: " . mysql_error();
    exit;
}
$sql = "SELECT id as userid, fullname, userstatus 
        FROM   sometable
        WHERE  userstatus = 1";
$result = mysql_query($sql);
if (!$result) {
    echo "Could not successfully run query ($sql) from DB: " . mysql_error();
    exit;
}
if (mysql_num_rows($result) == 0) {
    echo "No rows found, nothing to print so am exiting";
    exit;
}
// While a row of data exists, put that row in $row as an associative array
// Note: If you're expecting just one row, no need to use a loop
// Note: If you put extract($row); inside the following loop, you'll
//       then create $userid, $fullname, and $userstatus
while ($row = mysql_fetch_assoc($result)) {
    echo $row["userid"];
    echo $row["fullname"];
    echo $row["userstatus"];
}
mysql_free_result($result);
?>

注释

Note:性能

必须指出一个要点：mysql_fetch_assoc()比mysql_fetch_row()并不明显慢，而且还提供了更多有用的值。

Note:此函数返回的字段名大小写敏感。

Note:此函数将 NULL 字段设置为 PHP NULL值。

参见

• mysql_fetch_row()从结果集中取得一行作为枚举数组
• mysql_fetch_array()从结果集中取得一行作为关联数组，或数字数组，或二者兼有
• mysql_data_seek()移动内部结果的指针
• mysql_query()发送一条 MySQL 查询
• mysql_error()返回上一个 MySQL 操作产生的文本错误信息

Worth pointing out that the internal row pointer is incremented once the data is collected for the current row.
This means that multiple calls will iterate through the row data, so you DONT need to mysql_data_seek(..) between calls.
This is noted in the mysql_fetch_row() docs, but not here!?

It appears that you can't have table.field names in the resulting array. 
Just use an alias if your results come up empty and you are using multi-table query's:
$res=mysql_query("SELECT user.ID AS uID, order.ID AS oID FROM user, order WHERE ( order.userid=uID )";
while ($row=mysql_fetch_assoc($res)) {
  echo "<p>userid: $row['uID'], orderid: $row['oID']</p>";
}

It probably without saying, but using list() in conjunction with mysql_fetch_assoc() does not work - use mysql_fetch_row() instead.
<?php
$sql = "SELECT `id`,`field`,`value` FROM `table`";
$result = mysql_query($sql);
// this results in empty values for rowID,fieldName,myValue
list($rowID,$fieldName,$myValue) = mysql_fetch_assoc($result);
// this is what you want:
list($rowID,$fieldName,$myValue) = mysql_fetch_row($result);
?>

Note that the field names quoted within $row[] are case sensitive whereas many sql commands are case insensitive.

Fetching all the results to array with one liner:
<?php
$result = mysql_query(...);
while(($resultArray[] = mysql_fetch_assoc($result)) || array_pop($resultArray));
?>

Please be advised that the resource result that you pass to this function can be thought of as being passed by reference because a resource is simply a pointer to a memory location.
Because of this, you can not loop through a resource result twice in the same script before resetting the pointer back to the start position.
For example:
----------------
<?php
// Assume We Already Queried Our Database.
// Loop Through Result Set.
while( $queryContent = mysql_fetch_row( $queryResult ) {
  // Display.
  echo $queryContent[ 0 ];
}
// We looped through the resource result already so the
// the pointer is no longer pointing at any rows.
// If we decide to loop through the same resource result
// again, the function will always return false because it
// will assume there are no more rows.
// So the following code, if executed after the previous code
// segment will not work.
while( $queryContent = mysql_fetch_row( $queryResult ) {
  // Display.
  echo $queryContent[ 0 ];
}
// Because $queryContent is now equal to FALSE, the loop
// will not be entered.
?>
----------------
The only solution to this is to reset the pointer to make it point at the first row again before the second code segment, so now the complete code will look as follows:
----------------
<?php
// Assume We Already Queried Our Database.
// Loop Through Result Set.
while( $queryContent = mysql_fetch_row( $queryResult ) {
  // Display.
  echo $queryContent[ 0 ];
}
// Reset Our Pointer.
mysql_data_seek( $queryResult );
// Loop Again.
while( $queryContent = mysql_fetch_row( $queryResult ) {
  // Display.
  echo $queryContent[ 0 ];
}
?>
----------------
Of course you would have to do extra checks to make sure that the number of rows in the result is not 0 or else mysql_data_seek itself will return false and an error will be raised.
Also please note that this applies to all functions that fetch result sets, including mysql_fetch_row, mysql_fetch_assos, and mysql_fetch_array.

To sum up moverton at northshropshiredc dot gov dot uk and Olivier Fabre:
If the query is "SELECT something1, something2, .... FROM tbl WHERE some_condition", the keys in the returned array will be 'something1', 'something2', etc. *even for those "somethings" that are not just field names*.
Examples of non-fieldname "somethings" are:
NULL
NOW
MAX(some_fieldname)
I haven't tested whether this applies to table.fieldname, but I see no reason why it shouldn't (I'd suspect a typo in my code if I didn't get the expected results; I certainly have had my share of them!)
I found it most convenient to check for typos by simply var_dumping the resulting row, like this:
<?php
echo '<pre>Got this row:'
var_dump ($row);
echo '</pre>';
?>
where $row is the result from the last call to mysql_fetch_assoc.

When you have to loop multiple times through the result of a query you can set the result pointer to 0 (zero) with mysql_data_seek ()
The advantage is that you do not have to query database twice with te same query :)
So:
<?php
 $query = "
  SELECT *
  FROM database
 ";
 //Query database
 $result = mysql_query ($query);
 //Iterate result
 while ($record = mysql_fetch_assoc ($result)){
  print_r ($record);
 }
 ...
 //Point to 0 (zero)
 mysql_data_seek ($result, 0);
 //Re-use the result
 while ($record = mysql_fetch_assoc ($result)){
  print_r ($record);
 }
?>

Thanks to to R. Bradley for the implode idea. The following fixes a few bugs and includes quote_smart functionality (and has been tested)
<?php
  function mysql_insert_assoc ($my_table, $my_array) {
  
  //
  // Insert values into a MySQL database
  // Includes quote_smart code to foil SQL Injection
  //
  // A call to this function of:
  //
  // $val1 = "foobar";
  // $val2 = 495;
  // mysql_insert_assoc("tablename", array(col1=>$val1, col2=>$val2, col3=>"val3", col4=>720, col5=>834.987));
  //
  // Sends the following query:
  // INSERT INTO 'tablename' (col1, col2, col3, col4, col5) values ('foobar', 495, 'val3', 720, 834.987)
  //
 
    global $db_link;
    
    // Find all the keys (column names) from the array $my_array
    $columns = array_keys($my_array);
    // Find all the values from the array $my_array
    $values = array_values($my_array);
    
    // quote_smart the values
    $values_number = count($values);
    for ($i = 0; $i < $values_number; $i++)
     {
     $value = $values[$i];
     if (get_magic_quotes_gpc()) { $value = stripslashes($value); }
     if (!is_numeric($value))  { $value = "'" . mysql_real_escape_string($value, $db_link) . "'"; }
     $values[$i] = $value;
     }
     
    // Compose the query
    $sql = "INSERT INTO $my_table ";
    // create comma-separated string of column names, enclosed in parentheses
    $sql .= "(" . implode(", ", $columns) . ")";
    $sql .= " values ";
    // create comma-separated string of values, enclosed in parentheses
    $sql .= "(" . implode(", ", $values) . ")";
    
    $result = @mysql_query ($sql) OR die ("<br />\n<span style=\"color:red\">Query: $sql UNsuccessful :</span> " . mysql_error() . "\n<br />");
    return ($result) ? true : false;
  }
?>

What if you *want* a two dimensional array? Useful for output as an HTML table, for instance.
function mysql_resultTo2DAssocArray ( $result) {
  $i=0;
  $ret = array();
  while ($row = mysql_fetch_assoc($result)) {
    foreach ($row as $key => $value) {
      $ret[$i][$key] = $value;
      }
    $i++;
    }
  return ($ret);
  }
print_r(mysql_resultTo2DAssocArray(mysql_query("SELECT * FROM something")));
Array ( [0] => Array ( [symbol] => ARNA
     [datetime] => 2006-02-17 16:00:00
     [price] => 16.83 )
   [1] => Array ( [symbol] => CALP
     [datetime] => 2006-02-17 16:00:00
     [price] => 6.54 )
   [2] => Array ( [symbol] => CROX
     [datetime] => 2006-02-17 16:00:00
     [price] => 27.4 ))

Actually, Olivier, you're completely wrong about that, because there's a bug in your sample code. It will indeed return $row['MAX(time)'] - you have to pass the MySQL resource to mysql_fetch_assoc() and you're not doing that. This:
$row = mysql_fetch_assoc($conn)
...where $conn is your DB connection, would in fact produce a result. The complete example below is taken from my own self-written content management system:
$query = 'SELECT MAX(ctRevDate) FROM content group by ctPage';
$querySet = mysql_query($query, $conn);
$row = mysql_fetch_assoc($querySet);
print_r($row);
This produces:
Array
(
  [MAX(ctRevDate)] => 2004-01-15
)
..on my testbed. So it doesn't in fact need an alias at all.

function array2table: small fix to the post below that handles data returned from mysql that is either null or 0...
This is a useful script for displaying MySQL results in an HTML table.
<?
function array2table($arr,$width)
  {
  $count = count($arr);
  if($count > 0){
    reset($arr);
    $num = count(current($arr));
    echo "<table align=\"center\" border=\"1\"cellpadding=\"5\" cellspacing=\"0\" width=\"$width\">\n";
    echo "<tr>\n";
    foreach(current($arr) as $key => $value){
      echo "<th>";
      echo $key."&nbsp;";
      echo "</th>\n";  
      }  
    echo "</tr>\n";
    while ($curr_row = current($arr)) {
      echo "<tr>\n";
      $col = 1;
      while (false !== ($curr_field = current($curr_row))) {
        echo "<td>";
        echo $curr_field."&nbsp;";
        echo "</td>\n";
        next($curr_row);
        $col++;
        }
      while($col <= $num){
        echo "<td>&nbsp;</td>\n";
        $col++;    
      }
      echo "</tr>\n";
      next($arr);
      }
    echo "</table>\n";
    }
  }
?>
<?
// Add DB connection script here
$query = "SELECT * FROM mytable";
$result = mysql_query($query);
while($row = mysql_fetch_assoc($result)){
 $array[] = $row; }
   
array2table($array,600); // Will output a table of 600px width
?>

Here's a nifty function to copy a whole table to another table. Takes as its arguments
$z -> the result of a SQL query with columns matching the table you're copying into. 
$toTable -> string name of the table to copy into. 
$link_identifier -> the db resource of the table you're copying into.
If anyone can find a faster way to do this, I'd be glad to know about it...
<?php
function mysql_multirow_copy($z,$toTable,$link_identifier) {
  $fields = "";
  for ($i=0;$i<mysql_num_fields($z);$i++) {
    if ($i>0) {
      $fields .= ",";
    }
    $fields .= mysql_field_name($z,$i);
  }
  $q = "INSERT INTO $toTable ($fields) VALUES";
  $c = 0;
  mysql_data_seek($z,0); //critical reset in case $z has been parsed beforehand. !
  while ($a = mysql_fetch_assoc($z)) {
    foreach ($a as $as) {
      $a[key($a)] = addslashes($as);
      next ($a);
    }
    if ($c>0) {
      $q .= ",";
    }
    $q .= "('".implode(array_values($a),"','")."')";
    $c++;
  }
  $q .= ";";
  $z = mysql_query($q,$link_identifier);
  return ($q);
}
?>

In response to Sergiu's function - implode() would make things a lot easier ... as below:
<?php
  function mysql_insert_assoc ($my_table, $my_array) {
    // Find all the keys (column names) from the array $my_array
    $columns = array_keys($my_array);
    // Find all the values from the array
    $values = array_values($my_array);
    // We compose the query
    $sql = "insert into `$my_table` ";
    // implode the column names, inserting "\", \"" between each (but not after the last one)
    // we add the enclosing quotes at the same time
    $sql .= "(\"" . implode("\", \"", $column_names) . "\")";
    $sql .= " values ";
    // Same with the values
    $sql .= "(" . implode(", ", $values) . ")";
    $result = mysql_query($sql);
    if ($result)
    {
      echo "The row was added sucessfully";
      return true;
    }
    else
    {
      echo ("The row was not added<br>The error was" . mysql_error());
      return false;
    }
  }
?>
Thus, a call to this function of:
mysql_insert_assoc("tablename", array("col1"=>"val1", "col2"=>"val2"));
Sends the following sql query to mysql:
INSERT INTO `tablename` ("col1", "col2") VALUES ("val1", "val2")

Although deprecated as of PHP 5.5, the mySQL function do NOT trigger an E_DEPRECATED error