请问在PHP中将MySQL查询转换为CSV的最有效方法是什么？

最好避免使用临时文件，因为这会降低可移植性(需要目录路径和设置文件系统权限)。

CSV还应该包括一列字段名。

解决方案

// Export to CSV
if($_GET['action'] == 'export') {

  $rsSearchResults = mysql_query($sql, $db) or die(mysql_error());

  $out = '';
  $fields = mysql_list_fields('database','table',$db);
  $columns = mysql_num_fields($fields);

  // Put the name of all fields
  for ($i = 0; $i < $columns; $i++) {
    $l=mysql_field_name($fields, $i);
    $out .= '"'.$l.'",';
  }
  $out .="\n";

  // Add all values in the table
  while ($l = mysql_fetch_array($rsSearchResults)) {
    for ($i = 0; $i < $columns; $i++) {
      $out .='"'.$l["$i"].'",';
    }
    $out .="\n";
  }
  // Output to browser with appropriate mime type, you choose ;)
  header("Content-type: text/x-csv");
  //header("Content-type: text/csv");
  //header("Content-type: application/csv");
  header("Content-Disposition: attachment; filename=search_results.csv");
  echo $out;
  exit;
}

查看有关SELECT ... INTO OUTFILE语法的文档。

SELECT a,b,a+b INTO OUTFILE '/tmp/result.txt'
  FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
  LINES TERMINATED BY '\n'
  FROM test_table;

SELECT * INTO OUTFILE "c:/mydata.csv"
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY "\n"
FROM my_table;

(有关此文档，请参见：http://dev.mysql.com/doc/refman/5.0/en/select.html)

或者：

$select = "SELECT * FROM table_name";

$export = mysql_query ( $select ) or die ( "Sql error : " . mysql_error( ) );

$fields = mysql_num_fields ( $export );

for ( $i = 0; $i < $fields; $i++ )
{
    $header .= mysql_field_name( $export , $i ) . "\t";
}

while( $row = mysql_fetch_row( $export ) )
{
    $line = '';
    foreach( $row as $value )
    {                                            
        if ( ( !isset( $value ) ) || ( $value == "" ) )
        {
            $value = "\t";
        }
        else
        {
            $value = str_replace( '"' , '""' , $value );
            $value = '"' . $value . '"' . "\t";
        }
        $line .= $value;
    }
    $data .= trim( $line ) . "\n";
}
$data = str_replace( "\r" , "" , $data );

if ( $data == "" )
{
    $data = "\n(0) Records Found!\n";                        
}

header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=your_desired_name.xls");
header("Pragma: no-cache");
header("Expires: 0");
print "$header\n$data";

查看此问题/答案。它比@Geoff更为简洁，并且还使用内置的fputcsv函数。

$result = $db_con->query('SELECT * FROM `some_table`');
if (!$result) die('Couldn\'t fetch records');
$num_fields = mysql_num_fields($result);
$headers = array();
for ($i = 0; $i < $num_fields; $i++) {
    $headers[] = mysql_field_name($result , $i);
}
$fp = fopen('php://output', 'w');
if ($fp && $result) {
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename="export.csv"');
    header('Pragma: no-cache');
    header('Expires: 0');
    fputcsv($fp, $headers);
    while ($row = $result->fetch_array(MYSQLI_NUM)) {
        fputcsv($fp, array_values($row));
    }
    die;
}

如果我们希望将下载内容提供为可直接在Excel中直接打开的下载内容，则此方法可能对我们有用：(从我的一个未发行的旧项目中复制)

这些函数设置标题：

function setExcelContentType() {
    if(headers_sent())
        return false;

    header('Content-type: application/vnd.ms-excel');
    return true;
}

function setDownloadAsHeader($filename) {
    if(headers_sent())
        return false;

    header('Content-disposition: attachment; filename=' . $filename);
    return true;
}

这使用mysql结果将CSV发送到流

function csvFromResult($stream, $result, $showColumnHeaders = true) {
    if($showColumnHeaders) {
        $columnHeaders = array();
        $nfields = mysql_num_fields($result);
        for($i = 0; $i < $nfields; $i++) {
            $field = mysql_fetch_field($result, $i);
            $columnHeaders[] = $field->name;
        }
        fputcsv($stream, $columnHeaders);
    }

    $nrows = 0;
    while($row = mysql_fetch_row($result)) {
        fputcsv($stream, $row);
        $nrows++;
    }

    return $nrows;
}

这是使用上述功能将CSV文件写入$ filename给出的文件中

function csvFileFromResult($filename, $result, $showColumnHeaders = true) {
    $fp = fopen($filename, 'w');
    $rc = csvFromResult($fp, $result, $showColumnHeaders);
    fclose($fp);
    return $rc;
}

这就是魔术发生的地方;)

function csvToExcelDownloadFromResult($result, $showColumnHeaders = true, $asFilename = 'data.csv') {
    setExcelContentType();
    setDownloadAsHeader($asFilename);
    return csvFileFromResult('php://output', $result, $showColumnHeaders);
}

例如：

$result = mysql_query("SELECT foo, bar, shazbot FROM baz WHERE boo = 'foo'");
csvToExcelDownloadFromResult($result);