Online PHP editor | output for nNnBZ

<?php // mock class Sheet { public function setCellValue($a, $b) { echo "$a : $b\n"; } }; $sheet = new Sheet(); $ids = ["1", "2", "3"]; $fields = ["firstname", "lastname", "phonenumber"]; $data = [ ['a', 'b', 'bla'], ['John', 'Doe', '555-555-5555'] ]; // end mock //$ids = $_POST["id"]; //$values = $_POST["values"]; $sqlIds = implode(",", $ids); $sqlFields = implode(",", $fields); //$sql="SELECT $sqlFields FROM database WHERE id IN ($ids)"; //$result = mysqli_query($connect, $sql); //$data = []; //while ($row = mysqli_fetch_array($result)) { // $data[] = $row; //} // headers $colLetter = "A"; $rowNumber = 1; // A1...Z1 for header foreach ($fields as $fieldname){ $sheet->setCellValue($colLetter.$rowNumber, $fieldname); $colLetter++; } // A2..Z999 for the rest foreach($data as $row) { $rowNumber++; $colLetter = "A"; foreach ($fields as $i => $fieldname) { $sheet->setCellValue($colLetter.$rowNumber, $row[$i]); $colLetter++; } }