How to output a row from Table B based on a value in a row for Table A for every value of table A (SQL in PHP)
11:01 15 Feb 2026

So I have a table with 2 columns, parent ID and course ID. there is also a table with several columns, the course table, which has course ID as a column. I can isolate the current parent ID based on the log in data. for every row in the first table matching the current parent ID, I want to output the relevant course data via the course ID associated. a parent ID can have many course IDs linked to it. I am programming in php linked to a html site, and my tables are in SQL. Im sorry if this isn't very clear, I am an A level CS student and this is my first time with any of these languages.



    
    
    University
    


    


    

        query($sql); 
        $row = $result->fetch_assoc();
        $ParentID = $row['Variable'];
        $sql = "SELECT CourseID FROM parent_university_courses WHERE ParentID = '$ParentID'";
        $result = $connection->query($sql); 
        //$row = $result->fetch_assoc();
        //$CourseID = $row['CourseID'];
    
        //Fetch course data from the database
        //$sql = "SELECT SubjectName, Description, Images, GradeRequirement, UCASRequirement FROM university_courses WHERE CourseID='$CourseID'";
        //$result = $connection->query($sql);
        
        if($result->num_rows > 0) {
            //Output data of each row
            while($row = $result->fetch_assoc()) {
                $CourseID = $row['CourseID'];
                echo '
';
                $sql = "SELECT SubjectName, Description, Images, GradeRequirement, UCASRequirement FROM university_courses WHERE CourseID='$CourseID'";
                $result = $connection->query($sql);
                echo '';
                echo '
' . $row["SubjectName"] . '
';
                echo '
' . $row["Description"] . '
';
                echo '
' . $row["CourseID"] . '
';
                echo '
Grade requirement:   ' . $row["GradeRequirement"] . '
';
                echo '
UCAS requirement:   ' . $row["UCASRequirement"] . '
';
                echo '
';
                echo '
';
            }
        } else {
            echo "0 results";
        }

        $connection->close();
        ?>
php html sql heidisql