PHP - 由于双引号MYSQL查询而出错

Question

 <?php
   $query = "SELECT * ";
   $query .= "FROM subjects ";
   $query .= "WHERE id='" . $subject_id ."' ";
   $query .= "LIMIT 1";
 ?>

The problem cause is in this line: The error : "Database query failed: 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 'LIMIT 1' at line 1"

So why... despite the syntax is right. Given me that error ?!

Answer 1

You don't need to concatenate the variable you can use

 <?php
 $query = "SELECT * ";
 $query .= "FROM subjects ";
 $query .= "WHERE id='$subject_id' ";
 $query .= "LIMIT 1";
  ?>

You have two semi-colons after your variable as well, and if your variable is a integer, it doesnt need to be in single quotes either.