PHP SQL语法错误（没有线索为什么）[重复]

Question

This question already has an answer here:

• When to use single quotes, double quotes, and backticks in MySQL 12 answers

I am trying to execute an INSERT INTO query but for some reason an error is thrown.

$result1 = mysqli_query($connection, 
             "INSERT INTO `results` 
                     (`result_quiz_name`, `result_marks`, `result_grade`, 
                      `student_id`, `result_max_marks`) 
              VALUES ('Ionic Bonding Introduction', $marks, $grade, 
                $student, 5)");

The variable $marks is an integer, the $grade variable is a string and the $student variable is just the integer value of a session variable. The error that is displayed is this:

Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' 1, 5)' at line 1

I just can't seem to work out where the syntax error is. I have run this query in phpMyAdmin and it works fine (obviously substituting the variables for values).

Thanks,

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Answer 1

When a column type is text/string/char/varchar etc you have to wrap the variable in quotes in your parameter list, just like you did for 'Ionic Bonding Introduction'

$result1 = mysqli_query($connection, 
         "INSERT INTO `results` 
                 (`result_quiz_name`, `result_marks`, `result_grade`, 
                  `student_id`, `result_max_marks`) 
          VALUES ('Ionic Bonding Introduction', $marks, '$grade', 
            $student, 5)");