My sql and php query isn't working

Question

Hi my sql query isn't working, it's meant to select a student that has taken the same subjects and got the same grades from the sql database. I get the data from a form where the user enters previous student's information, this gets posted and stored in variables,then the sql query is executed.

I also get the error : Parse error: syntax error, unexpected T_LOGICAL_AND in /home/u717042829/public_html/predicter.php on line 117 which is ``` if ($autumn != "") and ($winter = "") and ($spring = "") and ($summer = "") {

```  <?php 

    //posted form data getting stored into variables ready to use
    if (isset($_POST['name'])) {


        $name     = $_POST['name'];
        $subject1 = $_POST['subject1'];
        $grade1   = $_POST['grade1']; 
        $subject2 = $_POST['subject2'];
        $grade2   = $_POST['grade2'];
        $subject3 = $_POST['subject3'];
        $grade3   = $_POST['grade3'];
        $subject4 = $_POST['subject4'];
        $grade4   = $_POST['grade4'];
        $attendance = $_POST['attendance'];
        $gender     = $_POST['gender'];
        $autumn   = $_POST['autumn'];
        $winter   = $_POST['winter'];
        $spring   = $_POST['spring'];
        $summer   = $_POST['summer'];


          // <--------------    Validation for form Post  ---------------------->



       // error a boolean variable if an error pops up error is assigned to be false
        $error = true;

        //validation make sure  2 of the same subjects haven't been chosen 
        if ($subject1 == $subject2 or $subject1 ==  $subject3 or  $subject1 == $subject4) {
           $error = false;
          } 
        elseif ($subject2 == $subject1 or $subject2 == $subject3 or $subject2 == $subject4) {
          $error = false;

          }
        elseif ($subject3 == $subject1 or $subject3 == $subject2 or $subject3 == $subject4) {
             $error = false;
            }
            // checks if the data entered is an integer 

      elseif ( is_int( $attendance ) && $attendance >= 0 && $attendance <= 100 ) {
      $error = false; // If the above condition is met, $error is set to false
    }


// code exectured if no error detected 
  if ($error) {



      //selecting from the database
      // using pdo statements and preparing the statements to prevent sql injections 
      // stores the query value of db into query
      // try ifset 

    if ($autumn != "") and ($winter = "") and ($spring = "") and ($summer = "") {
       $query = $db->prepare("SELECT * FROM paststudent WHERE subject1 = :subject1 AND grade1 = :grade1 AND subject2 = :subject2 AND grade2 = :grade2 AND subject3 = :subject3 AND grade3 = :grade3 AND subject4 = :subject4 AND grade4 = :grade4 AND autumn = :autumn");
        // binds the value to the query variable 
        $query->bindValue(':subject1', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade1', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject2', $subject2, PDO::PARAM_STR);
        $query->bindValue(':grade2', $grade2, PDO::PARAM_STR);
        $query->bindValue(':subject3', $subject3, PDO::PARAM_STR);
        $query->bindValue(':grade3', $grade3, PDO::PARAM_STR);
        $query->bindValue(':subject4', $subject4, PDO::PARAM_STR);
        $query->bindValue(':grade4', $grade4, PDO::PARAM_STR);
        $query->bindValue(':autumn', $autumn, PDO::PARAM_STR);
        // executes the query
        $query->execute();
        // the value of the query is stored to result
        $result = $query->fetch(PDO::FETCH_ASSOC);
    // fetch() instead of fetchAll just gets the first result



    }}


    //  ------ WINTER SELECT QUERY ------

      if ($winter != "") and ($winter = "") and ($spring = "") and ($summer = "") {
       $query = $db->prepare("SELECT * FROM paststudent WHERE subject1 = :subject1 AND grade1 = :grade1 AND subject2 = :subject2 AND grade2 = :grade2 AND subject3 = :subject3 AND grade3 = :grade3 AND subject4 = :subject4 AND grade4 = :grade4 AND winter = :winter");
        // binds the value to the query variable 
        $query->bindValue(':subject1', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade1', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject2', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade2', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject3', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade3', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject4', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade4', $grade1, PDO::PARAM_STR);
        // executes the query
        $query->execute();
        // the value of the query is stored to result
        $result = $query->fetch(PDO::FETCH_ASSOC);
    // fetch() instead of fetchAll just gets the first result



    }}



    // --------- IF SPRING IS TRUE -------

    elseif ($autumn = "") and ($winter = "") and ($spring != "") and ($summer = "") {
       $query = $db->prepare("SELECT * FROM paststudent WHERE subject1 = :subject1 AND grade1 = :grade1 AND subject2 = :subject2 AND grade2 = :grade2 AND subject3 = :subject3 AND grade3 = :grade3 AND subject4 = :subject4 AND grade4 = :grade4 AND spring = :spring");
        // binds the value to the query variable 
        $query->bindValue(':subject1', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade1', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject2', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade2', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject3', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade3', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject4', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade4', $grade1, PDO::PARAM_STR);
        // executes the query
        $query->execute();
        // the value of the query is stored to result
        $result = $query->fetch(PDO::FETCH_ASSOC);
    // fetch() instead of fetchAll just gets the first result



    }}

    // if statements to execute the relevant query 
    // ---------- IF SUMMER TERM IS TRUE ------ 
      elseif ($autumn = "") and ($winter = "") and ($spring = "") and ($summer != "") {
       $query = $db->prepare("SELECT * FROM paststudent WHERE subject1 = :subject1 AND grade1 = :grade1 AND subject2 = :subject2 AND grade2 = :grade2 AND subject3 = :subject3 AND grade3 = :grade3 AND subject4 = :subject4 AND grade4 = :grade4 AND summer = :summer");
        // binds the value to the query variable 
        $query->bindValue(':subject1', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade1', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject2', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade2', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject3', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade3', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject4', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade4', $grade1, PDO::PARAM_STR);
        // executes the query
        $query->execute();
        // the value of the query is stored to result
        $result = $query->fetch(PDO::FETCH_ASSOC);
    // fetch() instead of fetchAll just gets the first result



    }}
    // if the query fails then the user is submitted to the error page which gives instructions on how to resolve the error
    else {
        header("location:error.php");
    }
    }?>

Answer 1 · 2015-04-19T08:36:48Z

April 19, 2015 8:36am

You are incorrectly using parenthesis on the line in question:

if ($autumn != "") and ($winter = "") and ($spring = "") and ($summer = "") {

}

an if statement should be wrapped in a set of parenthesis, even if there are multiple conditions:

if (a == 1 AND $sky == 'blue') {

}

also, I noticed that you are not doing a comparison on $winter, $spring, and $summer, you are assigning them the string value "". One equals sign is assignment, two is logical comparison, so I think you mean if $autumn is not "" and $winter, $spring, and $summer are equal to "", which would translate to the following:

if ($autumn != "" and $winter == "" and $spring == "" and $summer == "") {

}

Answer 2 · 2015-04-20T10:00:21Z

April 20, 2015 10:00am

Thanks so much for your help Joe, sorry for being such a noob at programming.

My sql select query keeps on producing errors, not sure why.

  elseif ($autumn == "" and $winter == "" and $spring == "" and $summer != "") {
       $query = $db->prepare("SELECT * FROM paststudent WHERE subject1 = :subject1 AND grade1 = :grade1 AND subject2 = :subject2 AND grade2 = :grade2 AND subject3 = :subject3 AND grade3 = :grade3 AND subject4 = :subject4 AND grade4 = :grade4 AND summer = :summer");
        // binds the value to the query variable 
        $query->bindValue(':subject1', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade1', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject2', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade2', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject3', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade3', $grade1, PDO::PARAM_STR);
        $query->bindValue(':subject4', $subject1, PDO::PARAM_STR);
        $query->bindValue(':grade4', $grade1, PDO::PARAM_STR);
        // executes the query
        $query->execute();
        // the value of the query is stored to result
        $result = $query->fetch(PDO::FETCH_ASSOC);
    // fetch() instead of fetchAll just gets the first result

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Furquan Ahmad

Furquan Ahmad

My sql and php query isn't working

2 Answers

Joe Cochran

Joe Cochran

Furquan Ahmad

Furquan Ahmad

Joe Cochran

Joe Cochran

Furquan Ahmad

Furquan Ahmad