从SELECT查询返回行的num_rows问题[重复]

Question

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

I have an issue. I am trying to find out if a user's email already exists in the database here is my query:

$stmt1 = "select EmailAddress from customers where EmailAddress = ' .$emailaddress. '";
 $result = $db->query($stmt1);
 if($result->num_rows === 0){

     $Err = "";

 } else {

     $Err = 'This user is already registered login instead.';

 }

What am I doing wrong? I can't seem to get num_rows to return something I can work with. Shouldn't this query return 0 if no records are found or number of rows if there is a record?

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Answer 1

Use :

$stmt1 = "SELECT EmailAddress FROM customers WHERE EmailAddress = '".$emailaddress."'";