PHP-我在这段代码上遇到错误。错误显示，警告 : mysqli_query() expects parameter 1 to be mysqli, null 给出

Question

$q = "SELECT CONCAT" (lname ', ', fname) AS name
DATE_FORMAT(registration_date, %M %d, %Y) AS regdat FROM users
ORDER BY registration_date DESC;        
$result = @mysqli_query ($dbcon $q); 

Answer 1

引号中存在错误:

$q = "SELECT CONCAT(lname, ', ', fname) AS name,
             DATE_FORMAT(registration_date, '%M %d, %Y') AS regdat 
      FROM users
      ORDER BY registration_date DESC";
$result = mysqli_query ($dbcon, $q);