查询结果不会被回应

Question

I have a function. in that function in have a select query. another query should return the number of results that will be in the first query. I have this code:

    function name ($f){  
     global $db;
     ...
     $results = "SELECT `a` FROM `b` WHERE $where"; 
     $results_num = ($query = mysqli_query($db, $results)) ? mysqli_num_rows($results) : 0; 

     echo $results;
     echo $results_num;
    }

will echo:

SELECT `a` FROM `b` WHERE `keywords` LIKE '%abc%'0 

what is just $results but not $results_num? I do not understand why echo $results_num wont be shown and why there is a 0 at the end of $results so if there is someone who could give me advise to solve this I really would appreciate. thanks a lot.

Answer 1

Firstly, $results_num is zero and is being output (that's why there's a 0 at the end of your output). That's because this code is wrong:

$results_num = ($query = mysqli_query($db, $results)) ? mysqli_num_rows($results) : 0; 

Breaking it out a little:

$query = mysqli_query($db, $results);
$results_num = $query ? mysqli_num_rows($results) : 0;

And the second line should actually be:

$results_num = $query ? mysqli_num_rows($query) : 0;

You need to pass the query handle to mysqli_num_rows(), not the SQL.