Question

我正在将旧的PHP从mysql转换为mysqli，并在转换过程中遇到此错误。代码工作时没有在mysql下抛出错误但由于某种原因我得到了＃102;未定义变量：在第102行＆＃39;中的/xx/xx/xx/xx/xx/xx/vluchtbijtoestel.php中的prevcat。现在错了。我已经尝试将$ prevcat = $ cat添加到变量列表中，但这会破坏代码。

我的代码：

<?php
define('DB_SERVER', "xxx");
define('DB_USER', "xxx");
define('DB_PASSWORD', "xxx");
define('DB_TABLE', "xxx");

// Define your colors for the alternating rows 
$color1 = "#F0F8FF";  
$color2 = "#FFFFFF"; 
$row_count = 0;

// The procedural way
$mysqli = mysqli_connect(DB_SERVER, DB_USER, DB_PASSWORD, DB_TABLE);
$mysqli->set_charset("utf8");
$mysqli->set_charset("utf8");
$mysqli->query("SET NAMES 'utf8'");
if (mysqli_connect_errno($mysqli)) {
    trigger_error('Database connection failed: '  . mysqli_connect_error(), E_USER_ERROR);
}

$query = "
    SELECT vg.gegevenID, lvm.luchtvaartmaatschappij, lvm.sm_logo, vg.vertrekdatum2, vg.vertrekluchthaven, vg.aankomstluchthaven, vg.toestel, vg.inschrijvingnmr, vlg.vliegtuignaam, vg.vluchtnmr, t.toestel AS toestelnaam, lh.luchthavencode, lh.luchthavennaam, lh.countryflag, lh2.luchthavencode AS aankomstluchthavencode, lh2.countryflag AS countryflagaankomst, vlg.erlr, vlg.firstflight, DATEDIFF(vlg.firstflight,vg.vertrekdatum2) Age1, lh2.luchthavennaam AS aankomstnaam, CONCAT(t.toestel,' ', vlg.erlr) as toestelmeterlr

    FROM (tbl_vliegtuiggegevens vlg

    INNER JOIN (tbl_luchtvaartmaatschappij lvm INNER JOIN tbl_vluchtgegevens vg ON lvm.luchtvaartmaatschappijID = vg.luchtvaartmaatschappij) ON (vlg.inschrijvingnmr = vg.inschrijvingnmr) AND (vlg.lvmID = lvm.luchtvaartmaatschappijID)) INNER JOIN tbl_toestel t ON vg.toestel = t.toestelID

    LEFT JOIN tbl_luchthaven lh
    ON vg.vertrekluchthaven = lh.luchthavenID

    LEFT JOIN tbl_luchthaven lh2
    ON vg.aankomstluchthaven = lh2.luchthavenID

    GROUP BY  lvm.luchtvaartmaatschappij, toestelmeterlr, vg.inschrijvingnmr, vg.vertrekdatum2

    ORDER BY lvm.luchtvaartmaatschappij, toestelmeterlr, vg.vertrekdatum2 DESC, vg.inschrijvingnmr; ";

$result = mysqli_query($mysqli, $query) or trigger_error("Query Failed! SQL: $query - Error: ". mysqli_error($mysqli), E_USER_ERROR);

echo "
<table width='100%' border='0'>
  <tr>
    <td colspan='3'><strong>Luchtvaartmaatschappij</strong></td>
    <td width='17%'>&nbsp;</td>
    <td width='12%'>&nbsp;</td>
    <td width='19%'>&nbsp;</td>
    <td width='28%'>&nbsp;</td>
  </tr>
  <tr>
    <td width='2%'>&nbsp;</td>
    <td colspan='3'><strong>Toestel</strong></td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td width='3%'>&nbsp;</td>
    <td width='19%'><strong>vertrekdatum</strong></td>
    <td><strong>vliegroute</strong></td>
    <td><strong>registratie</strong></td>
    <td><strong>vliegtuignaam</strong></td>
    <td><strong>vliegtuig leeftijd op reisdatum</strong></td>
  </tr>
</table>
";

if($result) {
    while($row = mysqli_fetch_assoc($result)) {

    $row_color = ($row_count % 2) ? $color1 : $color2;
    $date1 = date_create($row['firstflight']);
    $date2 = date_create($row['vertrekdatum2']);
    $interval = date_diff($date1, $date2);
    $cat = $row['luchtvaartmaatschappij'];
    $subcat = $row['toestelmeterlr'];
    $item = $row['inschrijvingnmr'];


    if($cat != $prevcat){

echo "  <table width='100%' border='0'>";
echo "  <tr>";
echo "    <td><br /><hr></td>";
echo "  </tr>";
echo "  <tr>";
echo "    <td><strong><span class='style4'><img src='http://globe-trekking.com/vg/img/logos/sm/".$row['sm_logo']."'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;" .$cat. "</strong></span>&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp;<br /></td>";
echo "  </tr>";
echo "</table>";
        echo '<span style="color: #0A0094; font-size: 16px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'. $subcat.'</span><br />';//if the category has changed, we also want to show the new subcat
    }elseif($subcat != $prevsubcat){
        echo '<br /><span style="color: #0A0094; font-size: 16px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;' .$subcat.'</span><br />';
    }
echo "  <table width='1093' border='0' cellspacing='0'>";
echo "  <tr>";
echo "    <td width='75'>&nbsp;</td>";
echo "    <td width='200' bgcolor='$row_color'>" .date("d-M-Y H:i", strtotime($row['vertrekdatum2']))."</td>";
echo "    <td width='70' bgcolor='$row_color'><img src='http://globe-trekking.com/vg/img/flags/".$row['countryflag']."'> &nbsp;&nbsp;<abbr title=\"".htmlspecialchars($row['luchthavennaam'])."\">".$row['luchthavencode']."</abbr></td>";
echo "    <td width='70' bgcolor='$row_color'> &nbsp; naar &nbsp; </td>";
echo "    <td width='130' bgcolor='$row_color'><img src='http://globe-trekking.com/vg/img/flags/".$row['countryflagaankomst']."'> &nbsp;&nbsp;<abbr title=\"".htmlspecialchars($row['aankomstnaam'])."\">".$row['aankomstluchthavencode']."</abbr></td>";
echo "    <td width='150' bgcolor='$row_color'>".$row['inschrijvingnmr']."</td>";
echo "    <td width='250' bgcolor='$row_color'>".$row['vliegtuignaam'] ."</td>";
echo "    <td width='250' bgcolor='$row_color'>" . $interval->y . " jaar en " . $interval->m." maanden </td>";
echo "  </tr>";
echo "</table>";
    $prevcat = $cat;
    $prevsubcat = $subcat;
      // Add 1 to the row count 
$row_count++; 
}
}
mysqli_close($mysqli);

?>

Answer 1

把你的代码..你在if条件中使用$ precat和$ prevsubcat，然后再声明并定义它。

 $prevcat = $cat;
 $prevsubcat = $subcat;

后

$cat = $row['luchtvaartmaatschappij'];
$subcat = $row['toestelmeterlr'];

像这样

$cat = $row['luchtvaartmaatschappij'];
$subcat = $row['toestelmeterlr'];
$prevcat = $cat;
$prevsubcat = $subcat;

Answer 2

放

$ prevcat =''; $ prevsubcat ='';

Juste在“While”表达之前

此致

mysql到mysqli转换期间未定义的变量

2 个答案: