Forum

Code: Select all

Notice: Trying to get property of non-object in ...-

Code: Select all

 if ($result->num_rows > 0) {

Code: Select all

<?php
// Multiple select lists - https://coursesweb.net/ajax/

// Here add your own data for connecting to MySQL database
$server = 'localhost';
$user = 'root';
$pass = '';
$dbase = 'buswork';

// Here add the name of the table and columns that will be used for select lists, in their order
// Add null for 'links' if you don`t want to display their data too
$table = 'productosmodificados';
$ar_cols = array('marca','modelo','precio','proveedor','codigo','rubro');

//Here you can add extra columns with data for description
//Let it empty ( array(() ) if you not use additional column for description
$extra_desc = array('...1', '....2', '....3','...4','...5','...6');

if(!isset($_SESSION)) session_start();
header('Content-type: text/html; charset=utf-8');

$preid = 'slo_';  // a prefix used for element's ID, in which Ajax will add <select>
$col = $ar_cols[0];  // the variable used for the column that wil be selected
$nrc = count($extra_desc);
$re_html = '';  // will store the returned html code

// if there is data sent via POST, with index 'col' and 'wval'
if(isset($_POST['col']) && isset($_POST['wval'])) {
  // set the $col that will be selected and the value for WHERE (delete tags and external spaces in $_POST)
  $col = trim(strip_tags($_POST['col']));
  $wval = trim(strip_tags($_POST['wval']));
}

$key = array_search($col, $ar_cols);  // get the key associated with the value of $col in $ar_cols
$wcol = $key===0 ? $col : $ar_cols[$key-1];  // gets the column for the WHERE clause
  
// gets the next element in $ar_cols (needed in the onchange() function in <select> tag)
$last_key = count($ar_cols)-1;
$next_col = $key<$last_key ? $ar_cols[$key+1] : '';

$conn = new mysqli('localhost','root','','buswork');     // connect to the MySQL database
if (mysqli_connect_errno()) { exit('Connect failed: '. mysqli_connect_error()); }     // check connection

$_SESSION['ar_cols'][$wcol] = isset($wval) ? $conn->real_escape_string($wval) : $wcol;    // store in SESSION the column and its value for WHERE

// sets an array with data of the WHERE condition (column=value) for SELECT query
for($i=1; $i<=$key; $i++) {
  $ar_where[] = '`'. $ar_cols[$i-1]. "`='". $_SESSION['ar_cols'][$ar_cols[$i-1]] ."'";
}

// define a string with the WHERE condition, and then the SELECT query
$where = isset($ar_where) ? ' WHERE '. implode($ar_where, ' AND ') : '';
$get_cols = $key<$last_key ? $col : $col .($nrc >0 ?','. implode(',', $extra_desc) :'');
$get_cols = '`'. str_replace(array('`', ','), array('', '`,`'), $get_cols) .'`';  //add the column names between `..`
$sql = "SELECT DISTINCT $get_cols FROM `$table`".$where;
$result = $conn->query($sql);  // perform the query and store the result

// if the $result contains at least one row
if ($result->num_rows > 0) {
  // sets the "onchange" event, which is added in <select> tag
  $onchg = $next_col!==null ? " onchange=\"ajaxReq('$next_col', this.value);\"" : '';

  // sets the select tag list (and the first <option>), if it's not the last column
  if($col!=$ar_cols[$last_key]) $re_html = $col. ': <select name="'. $col. '"'. $onchg. '><option>- - -</option>';

  while($row = $result->fetch_assoc()) {
    // if its the last column, set a tablle with description, else, adds data in OPTION tags
    if($col==$ar_cols[$last_key]){
      $re_html .= '<table width="200" border="2"><tr><td>'. $row[$col] .'</td></tr>';  //start table with data from first column for description
      for($i=0; $i<$nrc; $i++) $re_html .='<tr><td>'. $row[str_replace('`', '', $extra_desc[$i])] .'</td></tr>';  //add data from $extra_desc columns
      $re_html .='</table>';  //end table
    }
    else $re_html .= '<option value="'. $row[$col]. '">'. $row[$col]. '</option>';
  }

  if($col!=$ar_cols[$last_key]) $re_html .= '</select> '; // ends the Select list
}
else { $re_html = 'Error en la tabla...resultado al menos una fila'; }


$conn->close();

// if the selected column, $col, is the first column in $ar_cols
if($col==$ar_cols[0]) {
  // adds html code with SPAN (or DIV for last item) where Ajax will add the select dropdown lists
  // with ID in each SPAN, according to the columns added in $ar_cols
  for($i=1; $i<count($ar_cols); $i++) {
    if($ar_cols[$i]===null) continue;
    if($i==$last_key) $re_html .= '<div id="'. $preid.$ar_cols[$i]. '"> </div>';
    else $re_html .= '<span id="'. $preid.$ar_cols[$i]. '"> </span>';
  }

  // adds the columns in JS (used in removeLists() to remove the next displayed lists when makes other selects)
  $re_html .= '<script>var ar_cols = '.json_encode($ar_cols).'; var preid = "'. $preid. '";</script>';
}
else echo $re_html;