警告：mysqli_fetch_assoc（）期望参数1为mysqli_result，第101行给出null [关闭]

Question

Im not sure why I'm getting this error. Line 101 shows as:

$sql_apr_i="SELECT SUM(total) FROM invoices WHERE YEAR(date_added) = YEAR(CURDATE()) AND MONTH(date_added) = 06 AND estimate = 0 AND user_id = '$user_id'";
$data_apr_i = mysqli_query($connect_db,$sql_apr_i);
$april_invoice = mysqli_fetch_assoc($data_april_i);

What am i doing wrong to get this error?

Answer 1

You have wrong variable name passed to mysqli_fetch_assoc. Try this:

$sql_apr_i = "SELECT SUM(total) FROM invoices WHERE YEAR(date_added) = YEAR(CURDATE()) AND MONTH(date_added) = 06 AND estimate = 0 AND user_id = '$user_id'";  
$data_apr_i = mysqli_query($connect_db, $sql_apr_i);  
$april_invoice = mysqli_fetch_assoc($data_apr_i);