Why is this returning bool(false)?

Question

I have this query that checks if a movement exists and supposed to return true or false. This query

function movement_performed_today($class_id, $client_id){
$class_id = (int)$class_id;
$client_id = (int)$client_id;



$query = mysql_query("SELECT COUNT(`movement`) FROM `completed_movements` WHERE `class_id` = '$class_id' AND `client_id` = '$client_id' AND `date` = CURDATE()");

$movement_performed = mysql_fetch_assoc($query);

$return = (mysql_result($movement_performed, 0) == 1) ? true : false;   
    var_dump ($return);
}

Returns:

bool(false) 
bool(false)

If I replace this code:

$return = result(mysql_result($movement_performed, 0) == 1) ? true : false; 
    var_dump ($return);

With this:

print_r ($movement_perfomed);

Returns:

Array ( [COUNT(`movement`)] => 2 ) 
Array ( [COUNT(`movement`)] => 3 )

Am I completely wrong to think since these numbers are anything other than zero it should return true?

Solution

To answer your question:

mysql_result returns FALSE on error. You are passing the array from mysql_fetch_assoc instead of the mysql resource as required by mysql_result's function signature:

string mysql_result ( resource $result , int $row [, mixed $field = 0 ] )

Thus it returns FALSE because it has an error.

---

A better way:

// Change
$movement_performed = mysql_fetch_assoc($query);
$return = result(mysql_result($movement_performed, 0) == 1) ? true : false;

// to
$movement_performed = mysql_fetch_row($query);
return $movement_performed[0] > 0;

This grabs the result of the count statement and does a > 0 check on it. The > 0 check is not really needed but helps show intent rather than relying on on truthy values.

---

Side note: the mysql_* functions have been deprecated. You should migrate your code to use MySQLi or PDO. You are unfortunately using the fact that many mysql_* functions do not need the mysql resource. Migrating your code will be a pain because you have to change a bunch of functions or declare global variables. I recommend the former option but it will take a lot of effort to fix.

Comments

[NullUserException]

mysqli_stmt_num_rows() (replacement for mysql_num_rows()) exists for a reason.

[Colbyd]

@LeviMorrison thanks for the help that worked. I posted the php loop above where Im calling this function and what Im trying to accomplish. Can you take a look and tell me what Im doing wrong when calling this functioin?

[Colbyd]

Now when I do a var_dump ($return) it get bool(true) bool(true) which is correct since movement does exist from this user in this class on this day. When I do var_dump (isPerformed) from the while loop it returns NULL and therefore executing the function which I dont want it do if returns true.

[Colbyd]

can you tell me what this line does $return = $movement_performed[0] > 0;

[Levi Morrison]

@Colbyd Did you actually say return $return; in your function? You have to return the result from the function. I edited my code example to reflect this.

[Colbyd]

my code currently looks like this $return = $movement_performed[0] > 0;

[Levi Morrison]

@Colbyd Change it to return $movement_performed[0] > 0; and see if isPerformed is still NULL.

[Colbyd]

that worked. Thank you...you'll have to forgive my ignorance on this. Im pretty green incase you couldnt tell.

[Colbyd]

now it returns bool(false) not matter if movement exist or not.