Php foreach在试图吸引学生时没有发挥作用

从上面的数组中，我将获得作业id分支。。现在，我正试图找到这些分支机构的学生。 我试过这样做，但有点不对劲，无法调试，有人能帮我吗

$stuBranch = $conn->query("SELECT student_pid FROM tbl_students
                WHERE graduation_branch = ".$v['id_branch']." ");

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缺少数组索引“id\u分支”

尝试：

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缺少数组索引“id\u分支”

尝试：

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与其说是$v，不如说是$v['id\u branch']

与其说是$v，不如说是$v['id\u branch']

通过以下操作减少您的开销：

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从输入数组中的单个列返回值

通过执行以下操作减少开销：

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返回输入数组中单个列的值

$v['id_branch']使用参数化查询。工作正常，谢谢。它是在数组中拆分的。我可以将所有学生存储在一个数组中吗？@AbdulWaheed:-它是在数组中拆分的。我可以将所有学生存储在一个数组中吗？这是什么意思？@chris85我同意你的看法。另外$v['id_branch']使用参数化查询。工作正常，谢谢。它是在数组中拆分的。我可以将所有学生存储在一个数组中吗？@AbdulWaheed:-它是在数组中拆分的。我可以将所有学生存储在一个数组中吗？这是什么意思？@chris85我同意你的看法。而且

$studentBranch = '';
  foreach ($jobbrnchesids  as $k => $v){
      $stuBranch = $conn->query("SELECT student_pid FROM tbl_students
                    WHERE graduation_branch = ".$v." ");
       $studentsWithBranches[] = $stuBranch->fetch_assoc();
   }
echo "<pre>";  print_r($studentsWithBranches); exit;

$stuBranch = $conn->query("SELECT student_pid FROM tbl_students
                WHERE graduation_branch = ".$v['id_branch']." ");

 $branchIds = array_column($jobbrnchesids,"id_branch");

 $result = $conn->query("SELECT student_pid FROM tbl_students
            WHERE graduation_branch IN (".implode(",",$branchIds.")");
 $studentsWithBranches = $result?$result->fetch_all(MYSQLI_ASSOC):[];

$studentBranch = '';
foreach ($jobbrnchesids as $k => $v) {
    $stuBranch = $conn->query("SELECT student_pid FROM tbl_students WHERE graduation_branch = '" . ['id_branch'] . "'");
    $studentsWithBranches[] = $stuBranch->fetch_assoc();
}
echo "<pre>";
print_r($studentsWithBranches);
exit;