Question

 $string = '';
  $q = $l = $count = $count1 = 0;
  // Query to get number of rows in table
  $query = "SELECT * FROM $section4";
  $result = mysqli_query($connect, $query);
  $numrows = mysqli_num_rows($result);
  mysqli_free_result();
  // Loop and switch statement for different "type"s of subsections in section
  while ($q <= 10) {
     // Reset values
     $test = $shown = false;
     $first = true;
     $count1 = ($q == 1 ?: $count1 + $count);
     $count1 = ($q == 2 ?: $count1 + $count);
     $count1 = ($q == 3 ?: $count1 + $count);
     $count1 = ($q == 4 ?: $count1 + $count);
     $count1 = ($q == 5 ?: $count1 + $count);
     $count1 = ($q == 6 ?: $count1 + $count);
     $count1 = ($q == 7 ?: $count1 + $count);
     $count1 = ($q == 8 ?: $count1 + $count);
     $count1 = ($q == 9 ?: $count1 + $count);
     $count1 = ($q == 10 ?: $count1 + $count);
     $group = $count = 0;
     $output = $numrows - $count1;


     $query = "SELECT * FROM $section4 LIMIT $output OFFSET $count1";
     $result = mysqli_query($connect, $query);
     while ($row = mysqli_fetch_assoc($result)) {
        if ($first) {
           $prev = $row["type"];
           $first = false;
        } //$first
        if ($prev == $row["type"]) {
           $prev = $row["type"];
           $count++;
        } //$prev == $row["type"]
     } //$row = mysqli_fetch_assoc($result)
     $query = "SELECT * FROM $section4 LIMIT $count OFFSET $count1";
     $result = mysqli_query($connect, $query);
     while ($row = mysqli_fetch_assoc($result)) {
        if (!in_array($row["classid"], $data)) {
           if (!$shown) {
              $string = $string . 'You need to take ' . $row["classname"] . ' (' . $row["classid"] . ')';
              $string1 = 'You need to take ' . $row["classname"] . ' (' . $row["classid"] . ')';
           } //!$shown
           else {
              $string.= ', and ' . $row["classname"] . ' (' . $row["classid"] . ')';
              $string1.= ', and ' . $row["classname"] . ' (' . $row["classid"] . ')';
           }
           $shown = true;
        } //!in_array($row["classid"], $data)
        else {
           array_push($taken, $row["classid"]);
           $totalhours = $totalhours + $row["classhours"];
           $group++;
        }
     } //$row = mysqli_fetch_assoc($result)
     $group0 = ($q == 0) ? : $group;
     $group1 = ($q == 1) ? : $group;
     $group2 = ($q == 2) ? : $group;
     $group3 = ($q == 3) ? : $group;
     $group4 = ($q == 4) ? : $group;
     $group5 = ($q == 5) ? : $group;
     $group6 = ($q == 6) ? : $group;
     $group7 = ($q == 7) ? : $group;
     $group8 = ($q == 8) ? : $group;
     $group9 = ($q == 9) ? : $group;
     $group10 = ($q == 10) ? : $group;
     mysqli_free_result();
     if ($shown) {
        $string = $string . '. ';
        $l++;
        $str0 = ($q == 0) ? : $string1;
        $str1 = ($q == 1) ? : $string1;
        $str2 = ($q == 2) ? : $string1;
        $str3 = ($q == 3) ? : $string1;
        $str4 = ($q == 4) ? : $string1;
        $str5 = ($q == 5) ? : $string1;
        $str6 = ($q == 6) ? : $string1;
        $str7 = ($q == 7) ? : $string1;
        $str8 = ($q == 8) ? : $string1;
        $str9 = ($q == 9) ? : $string1;
        $str10 = ($q == 10) ? : $string1;
     } //$shown
     $q++;
  } //$q <= 10

我的最终目标是让“$ count1”成为mySQL数据库查询的偏移量。 $ count1应该添加“$ count”以获得更新的“$ count1”值。但是，当我回显$ count1时，它会输出以下信息：

0 37 17 8 13 6 9 4 9 2 1

我理解我的代码很草率，数据库也是如此。这只是一个即将到期的学校项目。

我想转：

if($q = $value){ $count1 = $count1 + $count; }

为：

$count1 = ($q == 1 ?: $count1 + $count);

Answer 1

MDN的文档说：

从PHP 5.3开始，可以省略三元运算符的中间部分。如果expr1 ?: expr3评估为expr1，则表达式expr1会返回TRUE，否则会返回expr3。

你的表达：

$q == 1 ?: $count1 + $count

如果$q == 1评估为$q == 1，则

评估TRUE的值，否则评估为$count1 + $count。

由于==是ternary operator，$q == 1始终评估为TRUE或FALSE（＆＃34;评估为{{1}引用文档中的＆＃34; 表示＆＃34; logical operator＆＃34;）。

当TRUE为$q时，上面表达式的值为1，这可能不是您想要的。

我不清楚你到底想要达到什么目标。无论如何，equals to TRUE using loose comparison 不是是ternary operator的缩写形式，正如许多人想的那样。

Answer 2

难道不是更容易吗？..

if ($q >= 1 && $q <= 10) {
    $count1 += $count;
}

PHP三元语句不起作用

2 个答案: