PHP does not use open source libraries to export mysql data to Excel files

// Output the Excel file header, you can replace user.csv with the file name you want
header('Content-Type: application/vnd.ms-excel');
header( 'Content-Disposition: attachment;filename="user.csv"');
header('Cache-Control: max-age=0');

// Get data from the database. In order to save memory, do not put the data Read the memory at one time and read it line by line from the handle
$sql = 'select * from tbl where ...';
$stmt = $db->query($sql);

// Open the PHP file Handle, php://output means output directly to the browser
$fp = fopen('php://output', 'a');

// Output Excel column name information
$head = array('name' , 'Gender', 'Age', 'Email', 'Telephone', '...');
foreach ($head as $i => $v) {
 // Excel for CSV supports GBK encoding, must be Convert, otherwise garbled characters
 $head[$i] = iconv('utf-8', 'gbk', $v);
}

// Write the data to the file handle through fputcsv
fputcsv($fp, $head );

//Counter
$cnt = 0;
// Every $limit line, refresh the output buffer, not too big, not too small
$limit = 100000;

// Take out the data line by line, Don’t waste memory
while ($row = $stmt->fetch(Zend_Db::FETCH_NUM)) {

 $cnt ++;
 if ($limit == $cnt) { //Refresh the output buffer to prevent Too much data causes problems
 ob_flush();
 flush();
 $cnt = 0;
 }

 foreach ($row as $i => $v) {
 $row[$i] = iconv(' utf-8', 'gbk', $v);
 }
 fputcsv($fp, $row);
}

Easy to use, saves memory, and does not rely on third-party libraries , friends in need, please try it yourself.