php - 将 MYSQL 导出为 CSV，留下空字段

Question

我正在尝试将 mysql 查询导出到 csv。我让它工作，唯一的问题是它没有把空字段放在那里。我用管道将它们分开，|。我需要能够下载查询并将其上传到其他地方，所以我需要它来导出空字段。这是我当前的导出代码:

<?php


$from = $_REQUEST['from'];
$to = $_REQUEST['to'];
$filename = "APGE_ELEC_" . $to;
header('Content-Disposition: attachment; filename="'.$filename.'".csv"');

    $hostname = ""; //SET SERVER/HOSTNAME
    $dbusername = ""; //SET DATABASE USERNAME
    $dbname = ""; //SET DATABASE NAME
    $dbpassword = ""; //SET DATABASE USERNAME

$dbhandle = mysql_connect($hostname, $dbusername, $dbpassword) 
  or die("Unable to connect to MySQL");

$selected = mysql_select_db($dbname,$dbhandle) 
  or die("Could not select Data Base");


$query = "SELECT * FROM v88374 WHERE date >= DATE_FORMAT('" . $from . "', '%Y%m%d') AND date <=  DATE_FORMAT('" . $to . "', '%Y%m%d')";


$export = mysql_query ($query ) 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"; 

}

print "$header\n$data";


exit();


?>

我希望这不是一个巨大的修复。我感谢任何帮助。谢谢。

Answer 1

为什么不简单地做

SELECT whatever
FROM your_table
INTO OUTFILE '/directory/file.csv'
FIELDS TERMINATED BY '|'
ENCLOSED BY '"'
LINES TERMINATED BY '\n'

?

并且来自 manual :

... if the MySQL client software is installed on the remote machine, you can instead use a client command such as mysql -e "SELECT ..." > file_name to generate the file on the client host