尝试使用MySQL Update时出现令人沮丧的错误

Really quick but frustrating issue that I cannot seem to figure out!

I have a MySQL Query like this:

mysqli_query($con,"UPDATE jobs SET first_name = 'Borge' WHERE jobno='12313'");

And that works but as soon as I try and do this to put the actual values in it doesn't work.

mysqli_query($con,"UPDATE jobs SET first_name = '$first_name' WHERE jobno='$jobno'");

If someone could help me out that would be awesome!

mysqli_query($con,"UPDATE jobs SET first_name = '$first_name' WHERE jobno=$jobno");

please try this query it will help you and also add mysql_error(); at the end of your query it will help you to figure out the issue.